Powerchair Motors for Bikes...Brushless this time

I used to run CrazyBike2 on brushed powerchair motors with right angle reduction gearboxes, and that was ok, with the only real problem being the repeated chain and sprocket mangling from the incredible torque I could get out of them, and misalignment problems I had due to frame twisting (because of said torque).

Well, now I've got a *brushless* powerchair motor, direct drive rather than gear reduced, to try out.  This thread on Endless Sphere documents my exploration, modification, and testing of that motor, and will eventually show it's first tests on CrazyBike2, and it's later testing on the bike it's intended to be one of the various experimental power sources for. 

That bike is not yet named, and isn't finished yet due primarily to not having a reliably-working welder anymore, and secondarily from not having enough time to do everything yet.  There's a thread on it's evolution over on Endless Sphere, showing it's current progress.   The main thing I needed from this frame was stiffness, to prevent the flexing and twisting issues I had with CrazyBike2 with chain-drive motor power, whcih I still have issues with when carrying heavy cargo.  It'll use a mid-mounted NuVinci 171 developer's kit with autoshifting for a "transmission", to help keep power usage down (although it might not actually make it any more efficient due to the losses the NuVinci itself incurs internally). 

Also, to start it out from beginning as a full-suspension, since CrazyBike2 has broken lots of rear wheels while loaded down because of unavoidable bumps, potholes, and road debris, which shouldnt' cause such problems on a suspended wheel.  It will also use a motorcycle (Suzuki dirtbike, acually) rear wheel, which will take a lot more abuse than the bicycle wheels I have used so far.  I just need a good narrow "slick" tire for it, as the wide knobby it has now isn't really suitable for my purposes.

That's my update for now, hopefully I can keep coming back and adding info to the blog more frequently--but if you are a reader of it, and need more, I tend to post on at least one of my project threads on Endless Sphere ebike forums every day, and sometimes on several of them. 

Schwinn Sierra: From Junk to Ride

I decided for now that enough of the Schwinn was intact and in good shape that I'd spend a couple of hours and fit it out as a rideable spare bike, even though it is has no suspension at all, and is a regular straight-top (men's style) bike, which is really hard for me to get my leg up and over.

But it is very light. Even with the little rack I stuck on there, which is cheap steel and about 2 or 3 pounds by itself, plus the Stanley light full of 12 AA batteries, I can still lift it with one hand (not with my backpack/helmet on there, though).

I stuck the original front Kenda road tire off of DayGlo Avenger on there, as it is a lot better than the disintegrating front tire it had, and the Kenda Krossroads off the Trek, which is slightly better than the Kenda Road. Unfortunately, this Kenda Krossroads has the same problem my other Kenda Kross tires had--the sidewalls are not made right, and they shed bits of rubber off the fibers, eventually splitting along the diagonal fiber lines and coming open far enough to let the tube bulge out. This one is going to need patching inside just like the other two do.

I like the tire *style*, but their QC and/or sidewall design sucks. I sure wouldn't buy Kenda tires new, based on my experiences with all the ones I have had so far, including the pair that came new on DayGlo Avenger when I originally got it as a new-in-box Columbia Comfort Bike back in 2005 (of which the front tire on this bike is one).

That front wheel has the Slime thorn-resistant pre-slimed tube in it, too, as the original thin tube in there had several patches already, and was sticking to the inside of the disintegrating tire such that I didn't trust it.

This is what it looks like with no flash, and it's lights on.

My helmet light is on, too, and it is shining at the chair's right arm. It's a very diffuse LED light, without much of a spot. Lights up stuff close fairly well, and does a decent job of lighting up reflective road signs, license plates, etc, but not the actual road.

The Stanley light *does* have a really good beam, enough so that you can clearly see it on the wall in front of the bike (only a foot away, but still)

That spot stays a spot far enough away that I can't see enough light back from it to be useful, probably about 50 feet on road surfaces, farther on lighter-colored objects and much much farther on reflective ones.

It's a point source light from a distance, and quite bright; I keep it pointed at the ground about 20 feet ahead most of the time on the roads. Farther on unlit trails/canals. It's clamped to the bars with 2 hose clamps, like my other flashlights have been, and like the little red one is clamped to the junction of cargo rack and rear triangle.

I had to replace the sheaths for the shifter cables, though the cables themselves were fine. I swapped out the freewheel cassette for the one off the Trek, as the one on the Schwinn was very noisy, and the one on the Trek was virtually silent. I'm sure the original would work better if I serviced it, but I wanted to try the bike out for a bit before it got too late tonight, and I was getting hungry.

I tested it out for a few miles tonight, going to the store and stuff, and it worked well. Only problem I had was that the "Primus" thick tube that was already in the Kenda tire in back blew a hole (slit, actually) too big for even Slime to save it. I had to flip the bike over, peel the tire off the rim, and patch it, about a mile into the trip. No problems after that.

The hole was about 1/3 of the way up from the inside circumference of the tube, and looked like it was from someone using a screwdriver as a tire-iron, but on these tires and rims it's not even necessary to do that. They easily roll off the rims when deflated, which makes for easy fixing if something goes wrong, like above. I didn't even have to take the wheel off. I didn't see the mark when I originally swapped this onto the Schwinn's rim, but I did not look that closely at it. My mistake. :(

This bike is actually a joy to ride--it is so light and is geared right that I can start up without much knee pain, as long as I am not carrying anything. Adding the backpack with toolkit, pump, etc, plus wearing longjohn bottoms & top under the jeans and tye-dye long-sleeve sweater (for warmth in the chilly evening, made worse by the breeze from riding), was enough to make it harder to ride but still better than DayGlo Avenger even without it's cargo pod and rack.

I *don't* like the lower handlebars, though, so I will have to do something about that. The stem is already most of the way up, though, so I can't get enough height from it to help. I will probably have to change the handlebars to something that reaches farther up/back.

It is quite a tall bike and is not a joy to get onto. I can barely stand astride it, with the top tube against the seam of my pants. Wouldn't wanna slip off the seat. ;-)

I also don't like the seat, which is the original Schwinn narrow hard seat. Like all of them, it doesn't fit me and it's also slippery, so I can't seem to stay on it. It's a quick-release so I will probably use my shock-post seat if it fits in this tube (it might not). That seat is wider and at least somewhat tolerable for longer rides than a couple of miles. This one is mildly painful after only about a mile and a half; I probably could not ride it longer than 5 miles even if my life depended on it. ;-)

I'm pretty sure it was actually meant to have 700C rims on there, or at least something larger than the 26" that it came to me with, as the brakes don't adjust down the rims very far--the top edges of the brakes just clear the top of the rims by a millimeter or so at their lowest adjustment, but would go at least 1/4" higher--enough to ride completely on the sidewalls of the 26" tires!

If it did have taller wheels, I would not be able to ride it, though. I would be unable to mount it without holding it sideways so far that I could not push it upright to get it going, and I would be unable to dismount at stops, forcing me to lean over on one side while staying in the saddle. I'm not sure I could startup from a stop then, as most of them are on slight uphill inclines. It certainly wouldn't be easy.

Anyway, it's a good bike.

2QD Still In Progress, Now Using Curtis 1204-410 Controller

Since I have had so very little time to work on anything recently, I haven't finished the 2QD controller repairs or the physical repairs to the bike (wheel, chain).

The major problems were just the power output section (bottom two MOSFETs blown, gate resistors burned open as they were designed to). But one minor problem that kept anything from working right was a 9.1V zener diode that was only allowing 1.45V! So there was no internal power supply to run the entire comparator and feedback/control section, which is the majority of the controller.

I fixed that by replacing the zener with a 5.6 and a 4.1 in series, which while higher than the original still allows it to work. This got the main section working again, and now I just need to finish the power section as described a couple of posts back. I have wanted to use a different case for a while, so now is my chance.

Since it is taking a while to figure out and then make the holders for the FETs to line them up and keep them tightly against the case inside, and to polish the aluminum and the FETs for flatness and smoothness (for better heat transfer, since I have to use thermally conductive / electrically insulative pads, too), I decided to take a quick look again at the Curtis 1204-410 I have had for a few months with little time to troubleshoot.

I let it sit on the bench powered on (but not doing anything as it doesn't respond to input), for a while, and suddenly it started working, the motor attached to it began slowly spinning (the throtle was just a regular pot set to barely on). Apparently once it got warm enough (from me having the oven on to warm up the room), a connection was made well enough to start working.

There are six interconnect wires between the Curtis logic board and it's power board. Two carry B+ and two ground, and the other two carry signals. One is the PWM output to the FETs, and the other looks like a feedback from the FETs as it is time-shifted just a tiny bit late (which I can barely see at all with my old 531A), but identical to the PWM waveform.

The solder joints on them must've been flexed or vibrated enough to crack them, so they would only make connections good enough to work when warm or hot. Over 85F, anyway. Under that, they might work and might not. I reflowed the solder and now they always work.

Since it's a 36-48V 225A controller for brushed PMDC motors, it can be used in place of the 2QD, so for now I put it on CrazyBike2 and verified it works with the bike. I can use it until I finish the 2QD rehousing.

Now I need to build a new rear wheel, move the chain and some shifters and stuff from one of the spare bikes I got for parts from someone for Christmas, and finalize the new throttle control setup, and CB2 will be ready to ride more than just for tests.

I also cobbled together this temporary throttle lever and mounting, for using a powerchair's spring-return throttle on CB2.

The spring is so strong that without a pretty long lever, I cannot keep it pressed down for very long. Sorry the pic is so dark, but the flash keeps shining off the metal and the camera autodarkens the rest of it to compensate. :(

The aluminum bars are just end-pieces, uncut, off the rackmount fan enclosure from the same old studio-type Sony VTR the gray transistors from the last post are from. I'll probably wind up modifying a brake lever setup to use for this instead, as it will already be designed to clamp to the handlebar, and it has a long pivot arm.

Optionally, I considered using a lever-style shifter, but it is more complicated to set up for this, and it is also a much shorter lever.

Christmas Bikes For Parts

I wasn't expecting any presents this year, but I ended up with a few. Those NiMH packs in the previous post were a couple, and these two bikes as well. Pardon the stuff on the floor; Hachi was assimilating a bunch of junk mail just before I got home and I'd not had time to clean up the little tiny bits leftover. :-)

The first is a Huffy "Nevada". It's about the same as all the other Huffys I've had or seen, though at least this one has *indexed* lever shifters. Since they are for 3-ring and 6-ring, which I currently have on CrazyBike2, I'll probably move the shifters to CB2 in place of the ones I have (of which the rear one is an 8-speed so doesn't line up with the 6-ring cassette I have now).

It's a 26" wheel bike, with typical steel hubs but aluminum rims. Don't know what spoke type. Brakes are a center pull type I haven't seen before, but appear to work the same as some of the better OTS units I've got. Tires are knobby but not greatly so, and made more in a rounded fashion, so they ride a little better than most of the knobbys I have.

Cargo rack is cheap steel, and would not actually hold much in the way of cargo without wobbling or bending. Well, *relatively* much, given that I expect to be able to haul at least 40 pounds on any bike I ride, preferably up to 100 pounds.

One-piece cranks aren't useful, as I have lots of those. Overall this bike might just stay like it is as an emergency bike, for when experiments in progress on others aren't working or not completed enough to ride.

The other is more useful for parts, and is a Magna "Great Divide".

Like the Huffy it's a department-store 26" hardtail. But unlike the Huffy it has a front suspension fork. It also has square-taper cranks/BB, which is the type I need for jackshafts, and for the easily-changeable chainring sets I'd like to use.

It has grip-shifters, which I like on MTB style bars, but which don't work well for the downturned bars used on CB2, nor are they the safest thing to use with any ebike that has a twistgrip throttle (which I don't use now partly for that reason).

It also uses center-pull brakes, but a different style that is one I have seen, using the same mounting studs that linear side-pull brakes do. These are useful on any bike that has these studs, which many modern bikes, both cheap and high-end, do.

Has the same basic steel hubs and aluminum rims the Huffy does; tires are not as good though.


I have some ideas forming about using the above frame as part of a new version of CrazyBike2, but as a trike. One version of the idea is a tadpole, the other a delta. Since this is a 26" frame, I'm thinking of using a 26" rear wheel, and two 26" wheelchair wheels I currently have on that flatbed trailer right now. They have tubeless foam tires right now, but I'd change those to regular bike tires. Optionally, I could use a pair of 20" wheels meant for single-ended axle mounting. Either way, I'd make this into a full-suspension trike, if it's the tadpole version.

If I do it as a delta, I'd probably only have front suspension, unless I can figure out a way to make the rear wheels independently suspended. And independently driven, rather than a single axle.

It's much easier to build and drive the tadpole, especially as a full suspension. I just have to find all the right parts.

Blown MOSFETs Due To Chain Jam, Possible BMS Arrives for Li-Ion Pack

I have been having balanced karma of late--every time something really good happens, something equally bad compensates.

Yesterday on the way home from work the bike's rear chain (regular bike drivetrain part) somehow derailed and got tangled up, which actually pulled the entire right end of the rear axle and the derailer bolted to it off the dropouts and bent the rim up against the chainstay on the other side (the left end stayed bolted in), and then everything jammed and both bottom-leg MOSFETs blew.

The power meter registered over 3500 watts peak, 153 amps peak, which is a more than any of it is rated for--the MOSFETs I installed in my 2QD are only rated at 80A continuous, and can handle ~150A for *maybe* a second absolute max, with sufficient cooling (which they don't have in my setup, by any means). So it's no surprise they blew up.

All that only took about half a second as I was accelerating away from an intersection, crossing two lanes to get to a left turn I have to make to get home without going down a very busy stretch of road.

Then I had to drag the bike across the rest of the lane (while cars that weren't yet coming when this all started kept trying to go around me instead of letting me get out of their way!), up onto the concrete median, and spend an HOUR with traffic roaring by me, while untangling the chain enough to get the wheel off, unbend the rim and true it enough to get it able to roll. Then I had to take out around 6" of chain due to bent and broken links, and set it up to run only in lower gear in front since it was now too short for the big ring. Plus I had to take the motor chain off, since my pedals are linked to it and it is nigh impossible to pedal the bike without the motor running otherwise.

After that it was a heck of a ride home, at about 9MPH, which is just above the unstable speed of the bike, and I was totally worn out when I got home (and then had to go to a different job as handyman for someone else).

I didn't have the camera with me to take pics of the chain/etc, but wow, it was awful looking. It looked like someone had hit my rear wheel from behind and then stepped on it sideways, but it was just from being yanked so hard by the chain as it tangled.

The frame and dropouts all appear intact, but the wheel was seriously messed up. I will need to take it completely apart, restraighten the rim, and then re-lace it to get it back to anything close to really true.

The derailer cage was slightly bent but not badly, but the bolt that secures it to the little shaped nut that recesses into the dropout behind the axle had sheared thru as it was all pulled out. I am just lucky that I carry spare nuts/bolts in the toolkit, one of which happens to be the same thread pitch and diameter as that bolt--it is a bolt from a rackmount kit--it's so long that it prevents use of the highest (smallest) sprocket on the rear cassette, but as I had to pedal with no assist there was no way I was going to be shifting up that high anyway.

I guess the good news is that I *could* fix the problem on the road well enough to get home.


Here's some pics of the controller with toasty MOSFETs, before repair. I still haven't had time to go back and fix it yet; just replacing the MOSFETs and gate resistors (whcih also burned open as they are supposed to) didn't fix it. I'm too tired to try more now, after another day of work. Tomorrow and the next day I have to go help do a roof and some other things, so I won't be able to do it then, either. Fri and Sat I'm working again, so I don't know when I will find the time to finish troubleshooting it. Maybe Sunday. Should be easy, when I have time and am not too worn out to concentrate. (writing this post has taken several tries).

A close up of the damaged area. The discoloration around the screw on one MOSFET is actually the melted remains of the plastic insulator ring...it's still not shorted to the heatsink, but that insulator is totally destroyed from the heat.




This blown LiFePO4 BMS (sent by an Endless Sphere forum member) arrived today:

All that is known about it's problem is that a puff of magic smoke escaped from it somewhere, but not specifically where. With luck it's the MOSFETs, as those I have around here already.

Once I find and fix the blown part(s), then if I can figure out how to change it's HVC and LVC voltages to match those of my Li-Ion cells, I can use it as a BMS for my custom-built pack.

First, I just need to invent a time-machine that gives me extra time to do everything and still get enough rest....

Dualie Wheels, Mk II

I've discussed dualie wheels for the rear before, so that I can have more support back there, and less worry about a blown tire or tube, broken spokes, rims, etc. It's less of a worry once I have rear suspension, but the concern for a blown tire still exists, since as heavy as the bike is it is difficult to fix on the road. Less so if I use the suspension system I'm doing now, where the dropouts are fully behind the cargo pods, so I can at least get to them easily, but still not easy to do.

So I'm considering building a whole wheel from scratch, using the bearings and tube from this:
http://electricle.blogspot.com/2009/06/forks-sporks-springs-dorks.html
to make the axle, and welding up a hub, spokes, etc from there.

It's just small enough diameter that I can still fit the threaded part off of a regular hub (minus the bearing cups) over it with clearance, if that part is a bolt-on cover over the bearings.

Then I'd weld up a tube to fit between the bearings, weld on some flanges I can drill out for spokes and for bolting on the freewheel threading off a hub on the right side, and directly bolt on a sprocket on the left side (for motor use).

The flanges would be probably around 6" in diameter, so that I have plenty of clearance for spokes to be replaced without taking the wheel apart (unlike most bike hubs, where you have to take the freewheel or cassette off of it first, since it always seems to be drive-side spokes that break).

That also allows for many more spokes than usual, so I could use 72 spokes, 36 per rim, and have them fully supported. I might choose to not even weld them together, so that they are "independently suspended" as it were, with the spokes.

The rim would otherwise be the dual-rim welded with spacers as suggested by Scrapyard Don above.

It's difficult to imagine from what I am saying, I'm sure, but I have a fairly clear idea of how I'd do it, if I can find all the right parts in my junk pile. I'll try to come up with some sketches at some point.

Suspended!

So far, I've bent a couple of cheap rims (one aluminum and one steel) and one steel axle, because of potholes and such that couldnt' be avoided, due to the weight of this bike and no rear suspension. :(

I definitely need to come up with a suspension on this that leaves the rear wheel able to avoid such severe shocks. Something that suspends the cargo pods, and doesn't leave them on the pivoting part. The only one I can think of right now would put the rear axle directly onto a pair of plates mounted to the ends of some (unfortunately heavy) shocks I have, and some framework to give that a good pivot point. I don't think I could make it work well with only one side shocked, and there's not enough room to use only one of the shocks under the seat to the frame, totally outside the wheel diameter. Maybe if I passed it just under the sling of the seat but above the seat frame, but then my butt would be riding on the shock. No thanks. ;)

The big problem is that these pods need the stability of the rear triangle being fixed to the rest of the frame in order to carry the cargo I sometimes need to move around, so it is not going to work unless I leave that frame and build a totally new rear wheel frame that will still fit within the original triangle.

Or else, move the whole rear wheel back further (it's already a danged long bike!) and affix the pivot to the dropouts, with the shocks pushing against some tubing welded to the ex-seatpost. Physically it would work, but hte bike would be about a foot or so longer. Maybe nine feet total!


A question asked of me is why not move some weight forward?

I already have all the weight I can put forward as far as it will go, without putting it higher than I would like due to handling concerns, since anything forward of the handlebars has to go above where my legs and feet move for pedalling, and above and behind the front wheel for turning. It also has to be below (or to the side of) the steering tie rod just above the front top tube. That's really a pretty small volume.

The only possible thing I really considered doing is cutting the top tube of the front frame, bending it upward so it's join with the handlebar stem headtube would be a few inches higher and rewelding it (with some extra tube to fill in the gap). That would give me just enough space to put a fourth 12V 17Ah SLA in there to turn it into a 48V machine. But that's another 15 pounds of weight for not all that much gain.

If I made a small lockable metal box bolted between the front top and down tubes, I could store the several pounds of tools I always carry, and maybe the air pump, but that's negligible compared to the rest of the weight that is still back there (me plus any cargo I carry, which could be over 100 pounds of stuff sometimes).

Technical Difficulties Mark II; 4-Pole Motor Installed

First, the good news: The 4-pole motor is finally installed and tested as well as expected.

The bad news: today was filled with "technical difficulties":

--Tire has been going flat so something isnt' being plugged by the Slime. Took wheel off and tube out, to find one of the other patches has a split down the middle--poorly made patch, I guess. Glued a new patch from a different brand, waited the requisite time, inflated it to test, and the new patch has a tiny hole in it's exact center, which of course is right over the original hole. Scrubbed that off and put another patch on successfully this time.

--Put wheel back on, reinflated, rode around the block and SPANG! a spoke breaks. :( Not that that is unexpected, given how heavy this thing is and the fact it's all made of old junk. ;) Since the rim itself is bent anyway, I chose to just start with a different wheel entirely.

--This wheel doesn't have an axle (came that way, with gummy grease; must be pretty old). Take old axle out of old wheel, and find axle is BENT. Again, not a huge surprise, but I never noticed it causing a problem.... Got axle out of an old 10-speed wheel instead, and managed to get the wheel together and trued and whatnot, and reinstalled.

--Another test ride, works kind of ok, but something wierd is happening with the assist motor. I am not sure what it is, but it sounds odd, and that could presage a real problem I don't want to have on the road somewhere. I decide to finally just change the 2-pole motor for the 4-pole I've been putting off for months.

--After much ado, get the 4-pole installed and the bike back together for another test ride. Chain comes off the motor sprocket about three trips around the block later. The torque of the motor (which is MUCH higher than the old one, at least twice as high) is pulling so hard on the chain that it actually is pulling the motor backwards in it's mounting slots despite being bolted down very tightly. To fix that, I'll have to make a different mounting plate that doesnt' have slots but rather only fixed bolt holes, which won't allow for tensioning the chain in a normal way. Not happening today.

--Since the chain will only come off if I pedal harder than the chain pulls, I decide to test it longer without any pedalling, just resting my feet on them instead, as they go round. Seems to be working fine, so I head out of the neighborhood for a longer test. First big bump I hit knocks it off anyway.

--Some 15-20 minutes of messing around with some plastic and tape and zip ties makes a sort of chain tensioner, hopefully enough to last me on the way home (it did), and head back. It's now dark, and I can see sparks in my wiring harness along the top tube. :shock: That's VERY bad. I find that one of the batteries is shifting around and a post is touching the frame, shorting across one battery. :oops: Tightened down and fixed, but now the wiring harness is damaged--some of it has melted together, and my front headlight no longer works. The midships one still does, so I'm still road-safe.

--The lefthand shifter starts to act funny, and wont' stay shifted to the highest gear unless I hold it. Dunno why yet; I ziptied it in place as I only need the lower two for hills.

Speaking of shifters, I also found when doing the 4-pole install that I had inadvertently gotten the cable for the rear shifter inside the hose clamp for the front of the seat-frame connection. It slightly crushed the housing, which explains why it has been getting harder to shift the right shifter, for the rear cluster, and less reliable when it does shift (skips several gears, etc). I'll have to replace that part of the housing. That's going to be annoying.


As for the 4-pole motor, it works quite well, and is pretty zippy off the starting line from a dead stop. I can actually feel myself being pushed back in the seat, with my feet not even on the pedals, if I startup from say, 5th gear from top (of 21).

I am certain that it takes significantly more current than the 2-pole, but both of them are beyond the meter's capability to read (12A on the analog panel meter). I have to put the HF DMM in there to see if it's less than 20A (it's max displayable amount).

This motor should be 650-750W actual power handling capability, designed for 24V. At 36V, it should be able to draw less current to do the same work, so it should be able to handle 27A steady at 24V, and 18A steady at 36V, assuming the low end of that range, 650W. Of course, 18A steady would kill my batteries in less than 15 minutes, assuming I don't want to drain them past 50% DOD. I try not to drain them even that far, where possible.

It does have a distinctive noise though: It sounds like the servo motors in robots on TV shows and movies. It's a little annoying, but I'll get used to it, especially for the better acceleration I get from it.

Because of the higher RPM of this motor's gearbox, I used lower gearing (21 teeth instead of 24) at the motor sprocket to keep approximately the same speeds. I think I must've miscalculated though, because unless something else is wrong and the rear cluster isn't shifting all the way up to the smallest ring only under load/on the road (possible, but didn't seem like it), then it simply isn't going as fast as it used to. 17.5MPH is about it.

Since I had to weld the chainring onto the motor hub, then I'll have to weld a different one on the backside of the hub and flip it over, to get the right max speed (20MPH) out of it. Probably a 22T ring. Gotta go back thru the calculations again.

Ooops.

Slick Tires Installed

Today was not a good day at all, so I did not get any of the testing with the old tires redone. By the time I was done being frustrated by life, all I felt like doing was installing the new tires to see how they work, so that's just about all I did.

I didn't fix the rightside rear axle-nut clearance problem, so I still have to take the rail loose to put it on or take it off. I think I'm going to go with the hole thru the cargo pod and rail to get to it--it's the easiest to do. Whenever I have a day where things are going better for me and I am not afraid I'll totally screw it up. :-(

Here are the new tires, on the bike:

If I had any spray paint, I'd give them white sidewalls. Since I don't, I'm trying to remember where I put the latex wall paint that's off-white, and I'll use that, even if it peels off later--the visibility factor of light colored sidewalls is large enough I want it back.

Here's a shot of them with some dirt on the treads, so you can see the contact area they have rolling over dirty pavement. Nice and wide area, compared to the MTB types.

Closer shot below:

Also shows the brakes, which need readjusting again.

Speaking of brakes, here's a shot of the rear wheel with new tire, plus the brake arm extensions I had to make:

The arms fit the 26" wheel fine, but they are about 1/8" or more from being long enough to hold the pads on the 24" rim without rubbing the sidewall even if I have them properly installed, before engaging the brake!

So I cut the slotted tabs off a set of bent up calipers off some junked bike and bolted these tabs to the existing arm tabs at an angle, giving me just the right positioning of the pads.

The pads are at the funky angle when not engaged because the downward force on the calipers is so strong that at speed if I brake hard the calipers are pulled downward at their wheel ends so far the pads would tear into the tire if I didn't do this. As they are, they end up gripping the rim perfectly once engaged, and angle normally to the rim.

I had tried some retaining tabs bolted to these tabs, with a hook that went up and over the frame stays above, but when I braked hard they just bent, slipped over the frame, and jammed the brakes against the rim so I had to actually unbolt the pads to get the jam cleared. So I'll live with the flexing until the calipers break off at the swivel/mounting bolt or something.

I like the feel of these tires a lot better than the old ones. It sort of feels like they might be doing better shock absorption, but I think it's probably just because I don't have any of the knobbly vibration I did before. It's especially noticeable in turns, because of the front wheel now being a smooth curved surface instead of rows of rubber rocks, basically.


Since I couldn't do any scientific testing today, I took some photos of the side-view of the contact patches for the various tires I had on the bike. They're not all on the same rims, since I didn't want to unmount the bike's wheels with the new tires just for this.

Front new tire:


Rear new tire:


Old front tire from powerchair:


Old MTB/road hybrid tire:


Original "roadmaster" wheel tires I started with:


26" Cheng Shin I use on my upright bike, which was in use on Crazybike2 for the rear most of this month until today.



That's it for today, except to report that I kept having the pedal chain come off and get jammed up in the rear sprocket during all riding today, about every few hundred feet, to the point where I finally got frustrated and just tied it up out of the way and used the motor for everything instead.

The problem is getting worse, but I cannot see *where* the slackness is coming from:

• There's no additional wear measurable on the chain at any point; I cannot see a difference between it now and when I marked it on the tape for making it up when i redid the frame.
• The chainrings don't seem any different, but I can't really measure those. Photos appear the same when I compare them.
• The frame itself does not appear to be bending or shifting, but I didn't do any accurate measurements right after the modifications to compare to now; it's just a by-eye thing.

The motor chain is not having a problem at all, just the pedal chain. And I can't see the mechanism by which it is being popped off, either, as it happens at random times, with no one thing causing it.

• I can hit a pothole or a bunch of bumpy road and nothing happens, but later if I am just cruising BAM it pops off, even with no change in speed, torque, etc.
• I can shift gears one time and it'll pop off, but the next shift doing the same thing doesn't do it.
• Pedalling harder than the motor is spinning (which puts tension on top of the chain and loosens the bottom) doesn't make it happen any more often than running the motor without pedalling at all (which forces tension on the chain along the bottom and loosens it on top).

So I'm stumped; I only know that it always happens at the rear end of the pedal chain, not the front. I'll have to put a chain tensioner back on to stop it from happening, because this sucks.

Coastdown Testing, Etc.

I had been planning on doing various types of tests for later comparison as I change things on the bike, but somehow I never ended up getting around to it. One of those tests was a coastdown test, to determine comparison data for later rolling resistance and aerodynamics tests.

Today I tried to do them, but it turned out to be almost a waste of time, because due to technical difficulties on the way home after the last test, I lost the paper I'd written the results down on when I stopped to fix the problems at some point. However, I'll post what results I do have, for later perusal, for what use they may be.

For the current tests, I used this donated analog ammeter, apparently from an old charger:

It's wired on the battery side this time, rather than the motor side, since the current draws should be lower based on the PWM multiplication effect, and maybe would all stay within the range of the meter (12A).

I tried the red HF DMM that I'd fixed, but there's something seriously wrong inside, as it got hot and began smoking at the shunt (visible easily thru the hole I'd cut to both keep the shunt ventilated and to resolder it thru if it failed again later) even with only 3A current thru it, so I decided to not use it for these tests. If I spent the time to fix it now, I wouldn't get the tests done.

Unfortunately, ultimately all the startup currents were still out of range of the ammeter, though operational cruising currents were roughly the same as they had been with previous tests of motor side currents using the HF DMM, several posts back.


Now, for the coastdown tests, I accelerated to 20MPH on a relatively flat stretch of smooth paved road, then as I passed a marker on the side of the road I cut all power, started the stopwatch function on a wristwatch, and coasted down to 10MPH (the point at which I begin having a little trouble keeping it stable--at 9MPH it's difficult and below that it's really problematic) and stopped the timer. I repeated this in the opposite direction, and did each run twice, to help eliminate wind, even though it was essentially still air at the time, noting each time down on paper, because I have a mind like a steel trap (everything comes out crushed and mangled).

The first test was the 26" already on there, so when I rode home after that test, I changed the whole wheel out for the previous 24", using the MTB/road hybrid tire. It also has the identical rear cassette as the 26", for some current tests under different tire diameters. After that I rode home and changed out just the tire to the gray powerchair tire identical to the front one. Then it was too dark to continue, plus on the last trip home after that test, I had my technical difficulties mentioned above.

I cannot remember any of the actual times, but there was basically no difference between these three rear tires:
(Gray 24" powerchair knobby on front in all cases)
26" rear road
24" MTB/road hybrid
24" gray p/c knobby
Maybe I'll redo the tests with the last tire on it before I do the tests with the new slicks.

There was also no significant difference between the battery side current draw for any of the 24" rears. The 26" rear, however, at the same gears as the 24" (using the identical rear cluster), was I think about 2 amps more than the 24" for accelerations; cruising at speed generally seemed around the same but fluctuated a lot more on 26" than 24".

With the 26", I also did a braking test from 20MPH, squeezing both front and rear brakes really hard to skid it and see how far I would skid, but the number was lost with the paper.

I couldn't do the test with the 24s since I did not have a rear brake with them. That I still have to add a crossbar to mount them on, and would test them then.

I did do a test with the 24" front gray knobbly only, while I had the 26" rear on there, but again, it was lost with the paper. :( I had planned to compare that to the 24" slick once I changed them out.

The problems I had later will be in the next post, to keep this one short and to the point.

Diet Continues; Decisions, Decisions....

I'm still trying to think of good weight reductions I can safely do, but there's not a lot yet.

• The frame mods already done took off perhaps 3-5 pounds.
• I might get a half a pound off by going to the single-cable multi-conductor thin-gauge wire for all the bike lighting and sensors and stuff, removing that scooter harness.
• I'll probably gain an ounce or two going to the all-LED lighting for the turn signals/marker lights, but I'll lose at least a pound by removing the other lighting system that was on the DayGlo Avenger (which I'd like to put back on it).
• The cargo pods and their attachment frame are maybe 15-20 pounds, empty. Part of that frame (the front half of the square tubing) is also the seat mount, though, so doesn't count.
  
• The batteries alone are I think 51 pounds. I'd have to go to something like A123 cells to get enough power in a lighter package that wouldn't be damaged by what I use it for.
• The difference between the 4 pole motor about to go on and the heat-damaged 2 pole motor about to come off is more weight added than I took off with those frame modifications.
• The front fork can lose around 5 pounds, maybe less, if I go to the non-shock fork. I'll gain at least two of that back if I add the headtube shock later.
• The steel front cranks are maybe 2 or 3 pounds heavier than aluminum ones would be (if I had any to spare for it).
• Can't get the seat any lighter.
• Handlebars are as light as they'll get for the shape I need, unless I could get some modern ones custom-made out of thinner but stronger tubing (or get lucky and find some scrapped like I did these).
• Those little white baskets that held the batteries before could take off a pound or so, but they will actually hold my backpack or something else, bungeed between them and the bottom of the seat, should I take the cargo pods off for any reason.
• There's nothing else I think I can safely remove from the bike frames themselves.
• The 26" wheel with wide steel rim is probably a couple of pounds more than a 24"; since I only really went to 26 because I had a lower-rolling resistance tire for 26 but not 24, I can go back to 24 once the tires arrive from All Electronics.
• The toolkit could probably be slimmed down a couple of pounds if I could standardize all the fasteners on the bike, so that any emergency roadside work doesn't require the large assortment of tools and driver bits that I carry right now.

Road Tires and Rolling Resistance.

A friend found All Electronics in California had some salvage NOS 24" road slick tires (ex-Currie Izip chopper front tires) for only $5...but couldn't take them on the plane. However, I checked with AE and they will ship them for a reasonable cost, so I skimped on a bunch of things on my last grocery run and ordered four, since it's unlikely I'll run across this kind of deal anytime soon, and I do need better rolling resistance tires, with a smoother tread. Of course, now I'll have a dozen comments from blog readers telling me about much better deals. ;-)

I figured four since then I have one pair plus two spares, or if I later use all three on a trike I have one spare. I can't afford any more than that.

Hopefully they'll ship them Monday, and be here within the week, if I'm lucky. Then I can test speed vs current compared to the tires I already have, as well as a coastdown test to see what difference they make in just plain rolling resistance.

I'll test first the already-mounted rear 26" with road-type tire, and front 24" MTB-style wheelchair tire. Next, the same front tire with the old 24" Schwinn-marked tire that is a cross between MTB and road; still knobbly but not nearly so much as the front one is. Then I'll pull both tires off and replace with the new smoother ones.

The coastdown test will be done hopefully somewhere with no traffic at the time, so I can concentrate on a stopwatch and the spedometer and the start point on the road, without worrying much about anyone suddenly being in my path or they in mine. Basically I'd just mark a point on the road at which to turn off the motor and coast down to a stop (or actually, down to a known speed, around 9mph in my case being the slowest it's really stable at), from a specific known speed (20mph, giving me the longest coast test, if I can).

I can't do the traditional coast to a stop because the bike is not self-stable at lower speeds than that, and I'd have to keep either wobbling and weaving to stay up, and then at some point start touching the ground with my feet to balance, which will all be significantly different each time I do it, and affect the run's results too much. So I just have to make a cutoff point in speed, and stop the timer there.

Repeat the test a few times with each tire set, and average the times, to help account for changing wind conditions.

This will also tell me something about the bike's aerodynamics (which are pretty awful, I'm sure), for later comparisons as I add fairing bits.

550 Miles Coming Up, Motor Changeout

I passed 500 miles sometime in the last week or so I think, and am now nearly at 550. That's the total miles on the whole bike/frame/etc, even though some parts have changed at various points in there. Here's to hoping it lasts at least that amount again, since it is taking far longer to get to the trike than I had expected.


Since I now have bolts that will secure the 4-pole motor in place, and the heat-damaged 2-pole motor gives me a good reason to swap it out, I'm going to try to do it this week, since I only work two days :( and packing/sorting is driving me crazy and depressing me too much to keep at it for more than short bursts before I have to do something else for a bit, then go back to it.

First I have to make a wedge-shaped box or plate to go between the new gearbox and the motor mounting plate on the frame, because the 4-pole motor has an angled top, plus a longer motor cylinder, which combine to mean that even with the cylinder touching the BB between the pedals, and the gearbox as far forward as possible without it's output shaft conflicting with the cranks' rotation, there's still a wedge-shaped gap between the gearbox's top and that mounting plate.

I'll be working on two ideas for making the wedge. One will just be wood to test the angle and see if that is sufficient, and if it holds up to tests without crushing/splintering or working loose from vibration/compression, I will just leave it. The other, if the wood isn't sufficient but does work, will be some steel plate welded into a wedge-shaped box, with reinforcement ridges inside next to the bolts, diagonally (making the interior an octagon).

The chainline shouldn't change more than a couple of millimeters laterally if I measured it correctly, so it should stay tracking fine once I put it under tension and tighten down the motor mounts.

Since it is a faster output gearbox, it'll use a smaller output sprocket on it's shaft, a 21T. This should keep the max output speed still down around something sane for pedalling along with it (since they're still linked, as I have not yet completed that sprocket adapter disc to then hook to the pedal freewheel and try it out).

I should get around the same final speed, but it should be able to handle a LOT more mass and accelerate a lot quicker (at the cost of using more power all the time, because it is 4-pole instead of 2-pole). Theoretically, it makes hill-climbing at speed much easier, but mostly it will make hauling cargo easier (especially if I carry extra batteries on the trailer).

Dualie Wheels

My mind is still working out wheel problems and solutions, all on it's own, because it keeps popping them up at the oddest times to tell me about them.

One of them would basically have me running "dualies" in the back, so even if one tire pops I still have the other, etc. It would use a double rim, with independent tires and tubes on each, but both laced to the same hub.

This would require a wider hub and axle, so I'd need to modify an existing one to lengthen it. The hub should be easy to do, but I'm not totally certain about the axle. I think I would have to do the axle first, and in addition to welding a section of another axle into the middle of it, I'd also want to lathe that down to flush surface and then weld some tubing over that that is longer than the added axle piece.

Then I would use one of the thicker-bodied hubs, cut it in half, place the axle between them (since it will no longer fit thru the axle hole from outside), and weld them together with proper diameter tubing sleeved over the outside of the central hub.

I'm not sure if everything would remain as hard as it should after doing that, so it might not work as well as I'd like.

I'd need to use longer spokes for some of the cross-lacing, and I have some older likely 700c wheels that might have the right length. I am not certain how it will affect wheel strength to do this kind of lacing, where every other spoke will go to opposite rims.

Another option is if I have any hubs with enough space between holes to drill new spoke holes in them, I could drill a complete new set of holes in each flange, and lace up each rim to it's own set of holes.

A third option is to weld a second set of flanges on the hub, and give each rim it's own pair of flanges, just as if it were two wheels physically joined.

I'm not yet sure if I should weld the rims together or leave them so they can individually flex to handle loads on their own--I suspect the latter would be more effective.

The wider effective tire would probably make straightline riding a bit more stable, but introduce some funkiness in turning. Double contact patch means double rolling resistance, but it also means double drive power and double braking power.

Well, that is, if I also build a rim brake that's twice as wide. :) Or come up with some way to build disc brakes out of my junkpile of regular brakes, 5.25" harddisk platters, and other stuff like that.

I'm still pondering it, and may never even attempt it. More web research is in progress to see if anyone else has tried this and hopefully posted their results.

Whiny Wheels

Right at the moment, CrazyBike2 is undergoing a mutation with the 26" rear wheel tests. This is going much better using a wider steel rim with a regular 7-ring freewheel cassette than it did with the narrow aluminum one that bent.

Speaking of that, here's some pics of that rim. It's more obvious that it's bent without the tire on it.

I have it stacked on top of the rim I am going to use to replace it, once I get the freehub relaced into it.

Yeah, it's pretty bad. I'm surprised I couldn't really feel it that much while riding--it looks like I ought've been going THUMPETY THUMP down the road, but it didn't.

A side by side shot shows the rim i will be using is not quite twice as wide as the one that bent:

I'm hoping the extra width will also allow the tire to better support the bike, giving it more room for air inside the tube, and better side-loading resistance during turns, against the weight of the bike. Also when it's parked, since it rests on the bottom edge of one cargo pod, tilted to one side, plus the tires, it side-loads the wheel then, too, though it's static rather than dynamic.


I don't have it laced up yet, so I'm using one of the rims off the old Kensington "spare" upright bike, which I've been kind of parting out for some of my experiments and repairs to both this bike and the Columbia upright, my main "spare" bike (which is still short a rear wheel till I lace one up for it, since the bent one was from that, though I can in a pinch put the original first wheel it had back on, which has some truing problems I need to fix).

It's not as wide a rim as the one above, but it's close, and it's also steel. It has a regular thread-on freewheel hub, so I put the 7-ring cluster from the 24" wheel on to it, and back on the CrazyBike2. You can see it a little in the pics below (about the derailer). I've ridden about 10 miles on it now, and it works as well or better than the aluminum one that bent, and the current draw (and road speed per ring) is lower than it was with the freehub with the lower tooth count on each ring.

The tire I used is narrower and rounder than the Kenda Kross road tire I had been using on the bent rim, mostly because the chainstays are not far enough apart for that tire to not rub a little, even on a non-bent rim. I used the only other road tire I have, which is the "spare" for the upright DayGlo Avenger's front tire, a Cheng-Shin with a more car-like tread, which appears designed around a wet road environment (but is still smoother by far than any of the 24" tires I have).

I can still reach 20MPH on the next to highest gear, and haven't tried to see what the max is on the very highest, but I suspect around 22MPH, on motor alone. I don't intend to use that speed for anything other than emergency "passing gear" in case of a situation in which going faster is a better solution than braking, which does not happen very often, but on occasion has been something I would like to have had (would have saved me lots of panic).

Plus it would probably suck about 25-30A doing that, and kill the 17Ah batteries in only a few minutes.

The point of the bike is not speed, but rather range and ease of riding, as well as comfort and cargo capacity, all in roughly equal parts.

Now, I mentiond that the Cheng Shin tire is narrower than the Kenda Kross, but since I put it on the wider rim, it "balloons" out more because the bead is spread wider. Effectively, it is almost as wide as the Kenda, but not in the same place, so it's not as bad a problem.

So, until I get the chainstays spread a tiny bit more where the tire passes between them at the front, the little ridges (where whitewall would be on some tires) around it's sidewall rub ever so slightly on the chainstay tubes, just enough to cause a really interesting "robotic motor" whine while I'm at speed going down the road. It's such a high pitch it gets dogs looking around, but people can hear it too, for at least a couple hundred yards.

It sounds so strange, it grabs their attention. Not loud, but definitely an ear-catcher. Wish I had a quick way to record it, but it isn't picked up right by my camera. Gotta dig out the old recording studio stuff for the computer and set it up, before I fix the problem, because it is such an odd sound.

Funny that it would sound so much like a really high speed servo motor/gearbox, because the actual motor/gearbox is nearly silent!


Since I forgot to take pics of the "new" derailer, here's the one I'm using now:

You can see the gap between the top and bottom derailer wheel cages that lets one simply drop the chain right in there. I don't understand why they're not *all* made like that, because it is MUCH easier to deal with, and makes even pulling the wheel off to change a tire easy. Just lift the chain out, and now you don't have to deal with the derailer's spring tension pulling the chain taut while you're trying to pull the wheel out or put it in!

A clearer but more distant shot, above.


Another pic I forgot to take before, of the battery strapping:

It looks stupid, but it works fine until I get something better. Maybe someone will submit it to "ThereIFixedIt". ;-)

Phoenix Sinkhole Roads, Bent Rim, 26" Test Results

Here we call our place "Phoenix, City Of Gophers", because there are so many holes and "under construction" signs.

Heck, the "End Road Work" signs all say "Thank You" on them. I've even seen "Please" spray painted over the "Thank You" part.

But the worst is not the actual road work, it's the places that *need* it. There are numerous road edges, usually where traffic is pretty heavy and the only safe place to ride because of the traffic is the side of the road, where the asphalt is pushed up several inches in mounds and ripples from the intense heat plus the vehicle weight/etc.

Most intersections are so bad where they curve around, for right turns, that every so often they have to scrape off the excess because it sticks up as high as the curb! Sometimes it looks gradual as you approach it, until you're on top of it and WHAM.

Sinkholes are another huge problem, because they don't build roadbeds first, they just pour asphalt in layers till it's flat. When they repair it they don't even worry about the flat part, and usually it has undulations in it that'll make you sick if you ride over it at the right speed. Sometimes those are as much as an inch between trough and crest, too--I dunno what they use to "flatten" them but they aren't doing it right. It takes months to years for it to eventually settle down to flat from the summer heat, at the edges of the road, or on less-travelled back streets.

The sinkholes are super dangerous, because they look like any other small pothole until you're on top of it. Then it may be too late, if there's traffic. The whole sand and gravel underneath the asphalt just falls away over time, sometimes into broken sewer drains under the road, sometimes just the sand compacts with water over time leaving an unsupported asphalt sheet in places. Usually it breaks at the edges of the road, right where it joins the sidewalk or gutter.

I hit one today because of an impatient and stupid pickup truck driver with a trailer, who couldn't be bothered to either wait the minute until we reached the intersection and he could turn right, thus no longer caring about me being slow in front of him, or he could have passed me using one of the other two unoccupied lanes, even if only partly moving over into one, but instead he just honked and honked and laid on his horn, when I was already at the legal limit of 20MPH for my ebike (in the 40MPH street), at "as close to the right edge as practicable" based on the huge ridges and holes along that part of the road.

I waited until it widened out into a right-turn-into-a-parking-lot lane and scooted over a bit into that so he could pass, since he obviously was too stupid to use the other two empty lanes to the left of him to do it like a normal person, or just pass me super-close anyway like most people do in the daytime, and he gunned his engine, squealing and smoking his tires pulling against the load in his trailer, passing me but not very quickly. Must've been a pretty heavy trailer.

I started to pull back into the lane again before he was fully past me, simply because I was out of lane to stay in without climbing onto the sidewalk, and first I hit one of the ridges, then I managed to avoid the sinkhole with the front wheel but clipped the edge of it with the rear wheel, which slipped into it and WHAMMO against the farthest edge as I passed it.

The impact almost made my lower jaw into a bandanna, my spine into a pretzel, and actually knocked the chain off both my pedal drive on the left side and my regular bike drivetrain on the right, so I just coasted to a stop after I went thru the green traffic light, being unable to use pedals *or* motor to continue.

Walked the bike up into a parking lot and saw that not only did it jump the chains, but it also gave me a slightly flat spot on the aluminum rim I JUST installed on the bike LAST NIGHT to test using a 26" wheel instead of a 24", with freehub instead of freewheel, and my road bike tire (much better than the MTB knobby styles I'd had to use till now).

Great.

It's not flat enough to even really notice while riding, but I can see it. I can't really tell for sure unless it is rotating, though. But now the wheel is bent enough out of true side-to-side that it badly rubs the tire against the chainstays on each side during rotation. The axle *might* also be bent; it's a hollow-core with quick-release, which I don't like but can't change; it's larger diameter than any solid axle I have.

So now I get to take the whole bike backend apart again to change the wheel out (yeah, it's a crappy design but I don't have a choice with the parts I currently have available without some major changes to them). I'll take the freehub out and relace it into a different rim, and save straightening this one out for another time.

I'm recharging both the bike's batteries and mine right now, and when that's done, I'll go take it apart and see what I can do, with a steel rim this time, most likely.



Now, as for the results of the actual 26" wheel tests, it's a success.

First, I think with the smaller wheel it'd've been worse with the impact on that pothole, though being a steel rim it might not have damaged it (or maybe not as badly).

Second, the ride on the smooth-centered road tire was MUCH better.

An unexpected good thing is that the bike "feels" better in handling with the taller rear tire, even though it's only 1" different in ride height in the back. The slope of the bike is different, and even that feels better, oddly enough.

Third, that extra height makes a huge difference in the turning ability; I can lean much farther and turn sharper without hitting the cargo pods on the road.

Fourth, that freehub is way quieter than the freewheel--cruising unpowered when up to speed is almost silent (before the impact, at least-afterward it sounded like a nest of angry bees on a windmill blade...bzzzBBZZZZzzzzbbbzzzBBBBZZZBbbbbbzzz, from the tread rubbing on the chainstays).

The smaller rear cassette rings did actually end up making the bike ride about the same speed using the larger wheel. Since I'd also replaced the derailer and adjusted it so that it would always correctly engage the outer smallest ring (unlike on the other shifter/wheel), I managed to get to 20.2 MPH even against the very strong headwind (storm was blowing in) at the time. I might've been able to push that farther, but as that's the legal limit on the road, and I was only riding on the street this time (no testing in other places I might be able to try those speeds out, today). I didn't try pedalling hard with it, just a little bit. I might've been adding half a mile per hour with my own input. ;-)


The one problem is that using the smaller chainrings and the bigger wheel takes more motor current to do the same thing. A lot more. Where I'd been running average of 6 to 10 Amps for any particular gear and speed with the 24" and it's cassette, it took 11 to 16 amps to do the same thing on the 26" and it's cassette.

That's really annoying, because I like all the good things the 26" wheel gives me.

Obviously, I could lace the freehub into a 24" steel rim instead of a 26", since I have to move it anyway, and that'd give me the smaller chainrings for faster speed if I wanted it, plus the quietness of the freehub, and it's reduced friction.

But I still can't use the smoother road tires on it, and I think that is one thing I definitely like the feel of.

I also don't get the slightly increased rear ride height, and the good handling changes it brings.

A disadvantage of using the freehub at all is it's hollow axle and quickrelease spar, partly because it is not possible to fully release the lever and get the wheel out to fix anything without taking the whole rightside cargo pod off, and the lower mounting rail (at least, not without weakening that rail too much). Since the axle itself may be bent, it might be a moot point, unless I can replace it with a solid axle somehow (it's at least 1mm larger diameter than any other axle I have, so probably not).

So...I'm probably going to first test out a regular 26" steel rim (that is 1/4" wider than the bent aluminum one) with a thread-on freewheel type hub that I've already got laced up from previous stuff I did on my upright bike, using the cassette I'd already had on the 24" wheel. It's going to make the bike slower than it was, but that's going to remove the aluminum rim problem, and also the quick-release spar/lever problem, while still leaving me the handling improvements and road tires and whatnot.

Then I'm just left with it being a noisier freewheel, and taking more motor current to do the same job because of the larger wheel diameter.

The motor current does affect the range, but I got something like 11 miles in today on one charge, most of it at high motor currents and bike speeds (plus several miles with the messed up wheel rubbing on the frame!) and the pack was only down to 36.5V under load. It's at 40.2V floating when I start out after letting it sit for a few hours after a charge, about 39.5V under load. Totally dead would probably be about 30V, but I don't want to run it down that far, so I'd probably call it a day at 33V, maybe.

I guess I could up it to 48V, adding another battery, and gear the motor down more at the gearbox output shaft's sprocket, which is currently 24T (to a 52T receiver), changing to a 21T or less. I'm just not sure the motor will deal with double it's original voltage all that well, though it seems fine on 36V (as long as I watch the heat buildup).

26" wheel experiment

I've been planning to move the cargo boxes up to be level with the top of the tire, and get rid of the slanted rack, for a while now. Partly it would have been to make the top of it one single level surface I could put cargo all the way across, and part of it to raise up the boxes so that tight turns doesn't scrape them on the pavement, or high curbs catch the bottom panel when I have to get in the gutter from agressive traffic and/or poor road edge conditions. Kept putting it off because something was nagging me about it.

Turns out it's because the cargo pod with the lockable top would then either have to be moved back about 8", putting *all* of it behind the rear axle, or else I'd have to rebuild the top of it so it's hinged at the inside edge (nearer the tire) and locked at the outside. That'd require adding a lip reinforcement to the top edge of the current hinge side panel, so the lock would have something to hold against. Since it works the way it is now, and I have a lot of other things on my mind at the moment, I decided to leave it the way it is, since I'm also doing another experiment that will affect the most important problem, of the scraping.


I had to take them off anyway, to do this other experiment, so I took a few pics in the process.

Currently they just bolt on with four 1/4" bolts, two thru the top square-tube rail, and two thru the old rackmount rail on the bottom. On the left side it bolts right up to the face of the rails, and the right box has about 1" of spacers at the bottom so it will clear the derailer's full swing during shifting.

I did also remove the twisted remains of the fender support, which you can see just above the bottom rail in this pic. I had not done so in the months up to now because it required taking the pods off, and I had no other reason to do that yet. It's very light, and wasn't in the way, so I didn't bother.


The other experiment was to try a 26" wheel on the back instead of the 24", for several reasons.

First, because I only have road style tires for 26". All the 24" are MTB knobby types, though the gray wheelchair ones are less so in the center than most of them, and the Schwinn tire you see in the pics above is continuous all around the center band for 1/8" wide--not the full surface, but it's better than the knobbies. Still, with any of them I can feel the vibration from the tires even on smooth pavement.

Second, because I would like to see how much difference the extra diameter makes to the ride quality over dips and bumps, because on the 24" they're pretty bad, and it's not quite that bad on my 26" upright, even without the spring-seatpost. Also the extra air in the tire from it's larger circumference may make some difference; I'm not really sure.

Third, if I use the rear wheel off my upright bike, it's got a freehub instead of freewheel, and that means it's a LOT quieter, and based on test-stand spindown tests, it's also less friction than any of the freewheels I had then (one of them same as the one that's on the bike now). Still 7 rings, but slightly smaller numbers of teeth on each one, ranging from 27T down to 11T.

(BTW, on a previous post I'd said my current rear cassette was 28T down to 11T; it's actually 28T down to 14T--I was apparently remembering the freehub's cassette's smallest ring).

Due to the larger diameter of the wheel, I don't think it'll end up any faster because of the smaller rings, but it should essentially compensate for the larger diameter, if I am thinking correctly. (no, I didn't do the math; I'm going to test it anyway....)

I could lace the freehub into a 24" rim to test it, but I'd rather do all the things at once because it's a very simple wheel changeout this way, and it's already trued and whatnot, with the tire, tube, etc., all already on it.

The one big drawback is it's an aluminum rim, and about 1/4" narrower rim than the current steel 24" one I'm using. Long term that might not be good for it with the load this bike must carry.


Actually changing it was more difficult than planned, because this freehub uses a hollow axle and quickrelease spar. The lower cargo rails bolt to the dropout in such a way that while there's plenty of room for the solid axle ends and nuts/washers, there isn't enough room for the flip-handle end of the quick release. I had to notch the cargo rail to clear it, and unless I take a big chunk out, there is not enough room to fully open the release, so I can't take the wheel off without taking the rightside cargo pod off, then unbolting the rail, too.

I also changed out the derailer from the heavy steel old and heavily-used-in-testing SIS unit for the aluminum Suntour unit from Mark's old bike, which already donated it's smaller front chainring to the pedal freewheel (once that's completed). It's a nice design, allowing one to remove the chain from between the idler/jockey wheels without unbolting anything. Each half of the outer cage is independent on the right side, with a gap for the chain to go thru.

Since it had come from a non-indexed 10-speed, with only 5 chainrings to shift between, I wasn't sure it would work with a 7-ring unit and indexed shifter, but it does, once adjusted for high/low gear positions and tension adjusted.


I'd like to change the front wheel, too, but I'd have to pull the shock fork off my upright bike to do it, since this one is only 24" max, and the 26" would not even fit under the brakemount crossbar.


I took the rear rack off too, which forced me to finally bolt it to the back of the cargo pods.

Makes for a slightly less wiggly rear end, too, since it's bolted across the tops of them, keeping them from wiggling independently laterally for any reason, and much less likely to wiggle together (more damping).

While I was at it, I bolted the turn signals as far out as they'll go without sticking out past the edges or tops of the pods.

Another bit I did since I didn't need it to hold the front of the rack anymore was to move the seat top crossbar up and forward, so it becomes my shoulder rest. I have a tubular snap on pad from the top tube of a kid's BMX bike to put on there to actually rest my shoulders on, but hadn't run across it yet when I took the pics.

I also noted that while I still have the seat held on with radiator hose clamps, it's still as tightly affixed as the day I did it, and I had totally forgotten that I had intended to go back and drill bolt holes in the rails and seat bottom crossbars to bolt them together, once I'd worked out the ideal position for the seat. I guess the seat must already be ideal for me, since I didn't notice and forgot about ever adjusting anything. ;-)


Here's another great vid, nice and long with only about 5 seconds of relevant info, about 15 seconds in or so. :-)

You can stop it after that, or watch if you're really bored.

This time I was smart enough to start on the street, rather than leap off the driveway again like last time. It's testing the acceleration from dead stop using the 27T ring on the new rear cassette, plus the 42T ring on the front cassette, at full throttle. Normally I would change gears as it speeds up, but here I just let it go to see how it reacted, partly because at the instant I started, a car decided to come around the corner I'm facing, much closer to my side of the street than the one it should have been on. You see it parking later in the video.

Acceleration is pretty good, for the gear it's in with no shifting up, and no pedalling.

Wheel Dilemma

I had thought at first glance that I would be able to simply swap the wheels/hubs from the wheelchair to the ex-stroller/nee'-trailer's axles, but unfortunately they're different diameters.

The wheelchair axles are around 7/8", and the trailer axles are around 3/8". The sealed bearing units on both of them are, however, the same apparent outside diameter, for one side of the wheelchair hubs, but not the other. The inside of each WC hub appears to be the same as the trailer hub, but the outside of each WC hub is just very slightly smaller (perhaps 1/2mm), so the bearings from the one won't fit the other.

I haven't gotten the bearings out of either WC hub's inside holder yet to verify, but since the outside ones are recessed for the quick-release button, it's easy to see the problem, by attempting to insert one of the trailer bearings, which *almost* fits into the hole, but not quite. It's possible the inside ones are the same, but eyeballing them with the trailer bearing sitting on top of the WC bearing, it *looks* the same.

This means that unless I use the whole WC bearing, axle, hub, wheel, and mounting plate at the same time on one vehicle or the other, I can't use them at all. That's disappointing, as it makes my decisions harder.

If I use the WC wheels/hubs on the trailer, it'd make for a no-flats-causing-me-to-unload-cargo-to-fix-flat advantage. Also, would keep the trailer from bouncing around as much from the pneumatic tires, as the WC tires are solid, but can only be used on the WC rims. I don't think that in the condition they're in, that I could get them off the rims in one piece, or if I did that I could get them back on in one piece. I'd have to take them off to easily unlace the rim to use it with the trailer hubs, or to change the rims on the WC hubs for bike-sized ones, with pneumatic tires (probably would use 26" ones, right now).

The trailer rims/hubs are steel, 20". I can easily change the rims on these, so that makes them a better candidate for the trike wheels. I can also weld to the hubs if needed, and more safely machine them in various ways, so that I can attach whatever drive mechanism is necessary to them.

However, the trailer hubs are narrower, by nearly an inch, meaning they'll have less side-strength against stresses during turns, etc. This won't be a fast trike, but it will be heavy. Even with three wheels supporting it instead of two, it'll still need as much wheel strength as I can give it, while still keeping them light.

I think the trailer axles are smaller diameter mostly because they are solid, where the WC axles are hollow so the QR pin can move inside them. The QR pin itself could be bearing some of the load, too, I guess, but I doubt that it is--if it was, it'd be very difficult if not impossible to move it in and out with a load in the chair, and it's just as easy to move the pin in and out with the chair full (of big lead-acid batteries and other heavy objects) as empty.

I suspect they can both handle the same weight of load, but I *know* the WC was designed for at least 250lbs on it, while the former stroller only 75. Primarily I think that low limit is because of the plastic frame interconnects, and that the axles could bear much more, but I have no evidence for it, and can't find out without testing, which may destroy the axles if I exceed their limits.

Got more thinking to do.