Let's Build It Already!

Upon pondering some transmission thoughts, I think that at least for now I will setup a system to switch the motors from series to parallel depending on A) speed and B) steering. It is far easier to do this than to mechanically deal with huge reductions and shiftable drivetrains (other than an internally geared hub).

So series wired for startups and slower speeds. Once past a certain speed, will switch automatically to parallel, and not drop back to series until a couple MPH slower than that setpoint. The hysteresis will prevent the switching system from chattering and blowing stuff up. :)

I will need to learn to drop the throttle when the shift occurs, so I don't end up with sudden bursts of speed. I will probably put a light and maybe a beeper on there to alert me to an imminent shift, maybe 1/2 second before it happens, which should be enough to react to until I get a feel for it.

Since the main reason I wanted series motors was so that I could get an electronic differential for turns, it means that turning would need to be done at slower speeds in order to get that differential. For gradual curves it may not matter; have to test that. For sharper turns, such as from a N-S road onto an E-W one, I will probably need that differential.



Hmm....maybe a much better idea would be to build up the second 2QD and tweak them both to run identically when matched with their own motors, then use separate controllers with one throttle, compensated for an electronic differential by having a steering sensor that changes the proportions of left vs right motor throttle. It'd be more electrically complex, but also simpler in a number of other ways. It also leaves me with redundant controllers as well as motors and drivetrains, which is a nice feature.

I think I already have all the parts for a second one, including another metal enclosure (from an old external harddisk) similar to the Jensen inverter case I am installing the first one into.

This also means I can leave the Curtis on the CrazyBike2's motor, to which it is more suited (given that motor's short-term power capability).



I could not sleep last night (again, it's a common problem) so in between dozing just long enough to know I dozed as my head hit the keyboard, I looked up tilt-steering (leaning) trikes, all over the web.

I found a little information here on ES, which eventually got me links to links to links to a place called Jetrike, an open-source recumbent bike / trike project. The creator of it has plans and construction notes for a bike and a couple of tested trikes there, and some of the stuff looks very interesting. The most interesting part is that he has run simulations for the designs to see what would "really happen" before actually building anything. And has data tables and stuff for a few critical types of dimensions and how to work them out for a particular design. The trikes are deltas, but he started on a tadpole according to his pages there. I'd be super-interested in seeing what he comes up with.

However, the link to that project is broken, and there are no updates to the site that I could find since late-ish 2007. There is also a discussion link, but skimming thru it's archives I don't see any indication that he has proceeded with that project at all, which is very disappointing, as he did good work on the previous versions, and has hard data on why some things should or shouldn't be done, and how they might be improved to fix problems reported with various ways of building trikes (including fixes for rear-steering trikes, which are notoriously unstable and potentially very dangerous, due to flaws in layout of the tested versions, apparently).

Anyhow, I have many more ideas on a tilting trike, but I am still not confident at all that I could design something around that concept and make it work safely and reliably. Not with the stuff I just happen to have laying around, anyway.

There are others around as well, and many images and a few clear videos of some in action. I may be able to learn enough to actually design one of my own, though first I need to learn enough about the math involved to grasp the solutions in my head so I can come up with stuff without having to actually sit down and do all that math (at which I really suck).


I think I need to just build the thing first and get experience with a trike, then start working out version two that will have more features on it, probably including tilting.

I might even go ahead and build a pedal-only trike first, just so I can get that part working, and get a feel for ergonomics of the design based around my riding, and THEN work out a replacement for the front wheels/forks that lets me use the motors on there. I've been putting off this trike thing for so long because I didn't have this or that or a way to figure such and such out, etc., and I am really wanting to just get it STARTED!

CrazyBike2 Stalled

Not much progress on CB2 itself. Seems like every time I sit down to work on it either I find a serious problem with whatever it was I was about to do to fix the chainline stuff, or something happens to pull me away from it. Or fabricating something turns out to not be possible with the tools I have (or I don't have the skill to do it yet). It's kind of depressing. At least I have the trike design in progress to get excited about. :)

Using that smaller chainring off the Trek is impossible. It would bring the chain itself down to the point it would cut thru the frame. :( Any guide I put on there to route the chain around the frame would probably break under the motor power, probably when I have it heavily loaded and am far away from home. :roll:

To keep the chainline straight on the top where the load is, I have to keep a large chainring on the receiving crankshaft. So it is back to fixing one of the previously destroyed ring sets. Maybe I can mix and match them well enough to double up thinner rings, then use BMX chain for strength. Bolt or weld the ring set together.


Considering welding a threaded section from either a BB cup or a rear hub to the motor shaft's hub end, then putting a freewheel cassete smallest sprockets I can get away with on there. That would get me a freewheel so that I would not be driving the motor when pedalling.

Also considering taking a BB cup and welding it's cup end to the right end of the threaded part of a rear hub. Then welding it's nut end to the face of a steel square-taper crank. The cup would need to be bored out enough to be able to get to the nut and crank threads, so I could still tighten or remove it later.

That would give me a long enough threaded cylinder to do what I originally set out to do for leftside chainrings, which was to put a couple of freewheels on that threaded cylinder with spacers to line up the chains as needed, and allow both motor and pedals to drive the wheel without driving each other.

Problem is, I am not sure that the welding would take the torque, or that the crankshaft itself would take it either, with the load cantilevered out that far. Originally the custom-made cylinder design would have had the motor load still over the actual crankshaft, but both of these would end up out beyond the end of the shaft, putting quite a load on the welds.

So...CB2 is stalled.

More Broken Spokes, Need Rear Suspension

I'm pretty sure at this point that if I had rear suspension I wouldn't be having nearly the problems with the rear wheel that I do, so that is my next priority on this crazy bike.

Tonight I heard a rear spoke break TWANG as I hit a small 1" deep pothole around the diameter of my handspan, that I thought I avoided but didn't quite manage. As I stopped to see the damage, I could feel the tire rubbing against the frame in two spots, making it likely that there was at least one other broken spoke. There were four! All I could do at the time, about two miles from home, was to loosen some of the opposing spokes and tighten some of the ones around the broken ones on the same side, to eliminate the rubbing, and try not to abuse the wheel any more than necessary to get me home.

I'll have to take the wheel off and fix the spokes tonite, so I can head off to work tomorrow "worry free", as it were, but the worry that more spokes will break from the unsprung rear weight is not going to just go away.


I've had lots of ideas for rear suspension, most of which could be implemented reasonably easily if it weren't for the cargo pods needing to bolt the bottom rail to the rear triangle just above the dropouts. So I'll be creating a small piece of framework for the rear of the square tubing portion of the cargo pod rails, which are self-supporting, to "hang" the rest of the cargo pods structure from and keep them pushed outward at the bottom. I am not sure if this will work well until I try it out, but it is the only way short of a stiff tubing framework that will put the cargo pods fully outside the volume I need for the rear swingarm to move within.

Making a rear swingarm is technically not that hard, but may end up more difficult than I expect. The most compact option will simply remove the existing rear triangle and add a short extension to the front frame just under the seat that will hold the pivot point. The pivot point would be a BB and crank axle from a one-piece-crank type bike, of which I have several already disassembled for previous experiments. I'd leave the BB bearings partly exposed so I can get grease in there as needed, and then with no grease in it I'd weld the swingarm front end to the crank axle ends.

Alternately, I would cut a one-piece crank in half at it's center, then reweld it together as a U-shape instead of the S-shape it comes as. Then I can use the pedal holes in the cranks to bolt the swingarm to a little rearward of it's front end, and clamp it's front end to the cranks with some U-bolts, so that later on I can change things without cutting and rewelding, if necessary.

Either of those methods then requires a fairly compact spring, as there is not much room between the top of the ex-seatpost under the seat, and the front of the swingarm (perhaps 4 to 6"). I have a short and quite stout spring from a desk chair that is meant to preload it for tilting, which might help absorb a little bit of shock, but I would have to use something in addition to it to take up the preload of the bike weight plus myself, or there will be no compression left.

The other good springs I have are too long, and are meant to go outside a shock absorber from a motorcross bike (which I also have). These are about a foot long I also have the rear swingarm shock and spring from the Honda scooter, but it is also too long at around 10", and it is also probably not strong enough for this bike, as the Honda had a weight limit of only about 130 or 140 pounds, I think.

If I don't mind adding at least a foot to the length of the bike, I can bolt the front end of the swingarm *into the dropouts* of the existing rear triangle. This is easiest if I simply use the 24" rear triangle originally destined for the ReCycle that I never finished, as it uses square-taper cranks that I can easily just bolt to the dropouts.

This also makes it easy to use any of the shocks and springs I have; I could easily use the pair of motorcross shocks/springs, one on each side, and probably get a pretty good ride out of it.

Adding the new triangle plus the shocks would add at least 20 pounds to the bike, though. :-(

However, it is the best option, as it would also give me a place to put one more of those 17Ah batteries, for a 48V system and another 200Wh of power, which would give me about 18.6 miles of range at 80% DOD, with no recharge along the way, assuming 35Wh/mile. Right now, it's around 14 miles with three 17Ah batteries, by calculations. Realistically, I would get closer to 20-25 miles out of it, as I don't usually ride faster than 15-16MPH unless I'm in a hurry to get somewhere, and then it's 17-18MPH or maybe 19-20 for short trips--either of those eats up power too fast, though.

All told the battery plus the frame changes and shock and new triangle will add at least 35 pounds. So much for making it lighter. ;-)

But at least the weight will be sprung, so the rear wheel won't get destroyed by all the little holes and bigger potholes, plus the inch-or-more-high edges of driveways and such I must go over to get into parking lots and whatnot.

There aren't any pics for this post, as I need to get to fixing the problems now that I'm done with dinner, but there will be some of the spokes, and of some design ideas and parts, as soon as I can next post something. Also some pics of a couple of old 10-speed-type bikes I got for $5 at a yard sale a couple of days ago, one of which (a Schwinn 12-speed) has square-taper cranks (yay!), and both of which have lots of nice chromoly tubing, being very "tall" men's frames. I think that those bikes along with some other bits around here, including the old wooden seat from CrazyBike2, are going to become a Tour Easy clone, similar to that shown on the http://recycledrecumbents.com site. It'll be interesting to have a lightweight pedal-only recumbent not meant for cargo, but rather just for commuting.

Motor Rips Loose From Mounting Plate

(Much delayed posting due to holidaze and circumstances; was started thanksgiving night but not finished till the 28th)

Last week, on the way up toward Arrowhead along the canal, about 3 miles from home, the motor mounting plate gave way along the only rightside mounting bolt it had.

It looks much worse in person than I could capture on camera. The largest hole in it on the right rear of the plate is for the old motor's clutch lever to pass thru, and that weakened the plate enough in that area that the hole for the rightside mounting bolt of the new motor, right next to it and partly intersecting it, finally expanded and let the bolt pass thru it.

It took a small chunk of the plate out with it. This was during uphill travel on one of the under-road tunnels on the canal path; they're pretty steep. Not sure of the grade, but steeper than I can pedal up from a stop on my other unpowered bike, the DayGlo Avenger (the upright aluminum bike), without hurting my knees pretty badly even in the very lowest gear, and even that only at just enough speed to stay barely upright (if wobbly); perhaps 1-2MPH.

I didn't have any thicker steel plate, so I just cut another plate of the same material and same shape to weld to the existing one. First I had to hammer and bend the other plate back mostly flat, then I clamped them together, welded one edge (where it joins the frame), then clamped along the flat portion of the plates and welded thru the various holes in the plates (mounting screwholes from whatever they originally came off of) to the plate underneath, to join them more thoroughly. Not as good as a single thickness, most likely, but good enough for this, I hope. Sorry there aren't any pics of this process; again I didn't think to do it until too late.

After welding them, I did a lot of comparing, holding, marking, placing, and test-fitting of potential chainlines before I drilled any new holes, and before cutting the new slot for the chain to pass thru on the left edge of the plate (it's only major weak point now that there will not be slotted holes nor clutch lever hole).

Eventually I decided to do two things differently than before. First, to move the pedal crank chainring to the *right* side of it's spider, since it is a bolt-on to a flat plate.

This moves the pedal chainline right far enough to completely clear the motor chainline, even if I move the motor chainline more right as well. Then I did that, too, by flipping the hub over, cutting off more of the hub the same way I did it before (hacksaw while spinning it on lathe), and using the removed parts as spacers on the left.

This also allows me to center the motor better between the cranks, and it straightens the motor's chainline--part of the problem I had with it coming off (besides flex from the motor plate prior to failure) was that the chain had to be super-tight due to the chainline passing from left at front to nearly 1/4" out of line at rear, with no guide or jockey wheels to keep it lined up where it met the bottom of the receiver sprocket. So under the right circumstances (left turns with a lot of tilt, especially on bumpy roads or rough intersections, etc), it would come off, and sometimes tangle.

Now that won't happen, as the motor's chainline is as close to straight as I can see, as is the pedal chainline. The pedal chainline doesn't even need the tensioner/guide wheel anymore; even under bouncy conditions it stays on, so far, despite still being about 1/2 link too long.

I left the plate to bolt the wheel onto in case I have problems on the road; the wheel and bolt is in my toolkit.

While I was at it, I also welded up some battery retainer strips, just to give them some guide at the bottom, so I don't have to keep using the wood blocks (which deform over time and have to be readjusted) to keep the batteries from shifting around. For the front battery, I just used the bottom tray from a small standard computer UPS (the kind that uses a 7Ah battery), and cut a piece just long enough to tack weld onto the bike frame and still keep the bottom of the battery from moving side to side.

I cut a small slit for the hose clamp that secures the batteries to pass thru, for more clearance to the chain. No rubbing problems, even in a hard right turn. It does rub if the bike is tilted far enough to lift the rear wheel off the ground, using the right cargo pod as a "stand", but that's not relevant to riding it.

For the rear battery, which was the most problematic on the road, I took the two triangular strips left from cutting the new motor mount plate, and notched them to fit the frame and be out of the way of the motor bolts.

Then spot-welded to the frame and motor plate (as this also stiffens the motor plate some), and can now clamp the battery down without worries of it moving. Due to chain clearance, the clamp only goes around the rightside plate, but it is very secure and doesn't shift around even with that.

A quick shot of the PDA used as a bike computer, showing the readings at the time.

22MPH was unpowered gliding down into the tunnel that I had to walk the bike back out of due to the motor plate breakage. Usually (in daylight when I can see in the tunnel and it's entrances better) I can keep gliding until I am most of the way back up the other side, as long as there is no other traffic (normally there is not) or anyone sleeping in the tunnel with a cart full of their belongings (this happens more than encountering other traffic), and then I can engage the motor in a low gear and continue up the rest of the way.

This time it didn't work out like that, because when I engaged the motor, almost instantly the motor pulled out of the plate on the right side, which allowed it to be pulled left and back by chain tension, getting in the way of even the pedal chainline, which made me just stop right there, and set the parking brake lever (taken from the scooter) on the left, to the rear wheel. Then I saw what had happened, and just ended up walking the bike the rest of the way uphill, then walked it home via the surface paths.


Some new full-bike pics, including the headlight/taillight. First is the room light (same 15W/60W CFL that's in the HL/TL) and camera flash.

Next is just the room light, flash, and HL/TL.

Just the HL/TL

Just the room light, HL/TL. No flash.

Just the room light, no flash or HL/TL.


I've now gone another 31 miles, for 905 total, and the only thing I had to change (at 882 miles) was to weld the longer piece of hub that I'd cut off and used as a spacer, to the end of the hub it now sits against.

This is because the little pin that rests in the groove of both the hub and gearbox axle isn't long enough to totally fill the space from one to the other, and apparently can work it's way loose. The original one *was* long enough, but I managed to misplace it during my original modification of the hub, and had to make a new one; for whatever reason I no longer remember, I did not make it the same length. Now it's welded, *and* has a hardened torx-head bolt threaded into the groove for the rest of the length, to ensure full contact and power transfer between the axle and hub.

I was very lucky that it failed where it did, less than 1/4 mile from a friend with a welder and the large 19mm wrench it takes to undo that locknut, or I would not have made it home in any reasonable time that night--the motor couldn't transfer any torque to the drivetrain, and I could not have gotten the nut off to put the pin back in place (the washers block the pin from coming out, and thus anything I have from going in!). So my thanks to him for letting me barge in after turkey-day dinner and use his tools!

Chain Reactions, Part 3

After the work done in the last Chain Reactions, Part 2 post, I did 24+ miles yesterday in two trip legs (with a partial recharge at the far end, halfway). No problems with the chain coming off or anything unless I try to push the bike backwards.

Comes off at the motor end every time if I do that, because of the misalignment between motor ring and receiver ring. Have to cut at least 1/8", maybe 3/16" or more off the inner end of the hub to get the ring lined up again, and then use spacer washers between the locknut/retaining washer on the axle end and the hub to keep it from sliding back and forth.

The entire bike is very much quieter, and the motor is also quieter now; not sure why. Only annoying noise now is from the fixed-in-place guide/tensioner wheel on the pedal drive, thinking of replacing this with a guide tube instead, if I can find some of my tough plastic sheet that won't wear away from the rubbing. It might also be quieter as a sprung wheel instead of fixed, because the tension on it changes as the pedal and receiver rings go around, since they're not perfectly centered on their shafts.

Current draw with the 28T ring is higher by an amp or so (for same speeds as 24T), average, but I can also go higher speeds all the time because it's now reliable. :) I can also push the throttle to the max to accelerate, and I actually had the rear tire slip a bit on certain areas of older pavement (where the top layer is gritty and a bit loose, not sticky anymore especially since the weather is cooler now), during the first couple miles of the ride while the batteries were at full charge. That's kind of cool, in that it means I have *plenty* of torque available now, and I just need to get batteries to match the power draw of the motor for really good range at top speed.

I now get 20.0 MPH max speed on a level no head/tail wind, motor only, draws more than 12A (max panel meter reading) solid for a few seconds getting there, then tapers off and sticks around 10-11A to hold there. Pedal some and I can stay at that speed with motor dropping to 4-9A swinging wildly, but it doesn't increase the speed, which seems a little wierd, as I have no limiter on there for that. I still need to mess with the shunt and panel meter on that 30A meter to get it working again.

Seems like with 28T vs 21T, with the same rear ratio at the high end, I ought to get a lot higher speed than 20MPH, since around 18MPH was the max on 21T. Still pondering that one.

Wondering if perhaps the throttle adjustment inside the controller has coincidentally changed (vibration? the pot is not locked down and it does turn easily). I want to open it up and do the mods to up it to 48V capable anyway, so I can test with a fourth UPS battery, for kicks.

Still considering swapping the 3-ring set off the upright bike to this one, just to see what happens; I could then run on the middle ring most of the time instead of the big ring; bit less chain wear from running angled, since commonly I run at largest front ring (farthest right) and somewhere in middle on rear rings. I could also then run on the big front ring for faster speeds, which would have less ring wear on the back and more teeth to put the power into the rear wheel at any one time, rather than using the smaller rear rings to go faster, which leads to much faster ring wear and as I've seen, chain skip. :(

I do think I'm going to end up needing a lot of new chains based on the wear and skip problems now obvious with this heavy bike, or I need to find a way to seal up the chain and rings in a clean, lubed, dust-free enclosure. Road grit can't be helping the problems.

This is where the belt-based CVT in a sealed box would be nice. Still researching how I might be able to build one; lots of ideas but have to work out the mechanics using parts I already have--that's difficult.

Chain Reactions

As stated a couple of posts back, I needed a way to tension the motor chain so it won't come off, or mount the motor onto a separate plate with only fixed bolt holes instead of slots for tension adjustments, then bolt that plate to the existing plate. It's significantly more work to do the mounting plate, for various reasons, so I pondered some chain tensioner ideas first.

After a while of thinking, I decided to just try my other chain tensioner I'd previously used for the pedal chain, which was going to be my throttle control (that I haven't built the electronics for).

I found a "good" position for it that would also help wrap more chain around the smaller motor sprocket, as well as keep it tensioned and in-line for passing to the receiver sprocket, used some vise-grips to hold it in place while I spot-welded it to part of the unused dropout tab on this side.

Then I hooked a stiff spring thru the ex-brake-pad-mounting slot, and over the top of the dropout tab, and pinched it between the cargo pod rail and the dropout just to be sure it couldn't pop off.



There is a slight problem with it, though, as I found while on-road during a medium-length several-mile trip.

If you follow the pivot curve, you'll see that if for any reason the chain pops off the tensioner's wheel to the "inside", the entire arm will be pulled up by the spring and get jammed in the motor sprocket.

Yeah, that happened about 4 miles in, although I still can't see how it *could* come off the tensioner's wheel, as it is perfectly aligned, no wiggle or slop, and the spring is quite strong and should pull the chain tight even against bigger bumps (of which there were none).

But since the wheel is a narrow little thing, then whatever causes any misalignment sufficient to let the chain ride up on the teeth is going to be enough to also let the chain come down the other side, probably. Needs to be much wider, but with teeth in there it won't fit.

So I need to do two things:

--Move the pivot point farther back enough that the wheel and/or arm can't come in contact with the motor sprocket no matter what happens. May need to weld this to a plate that gets bolted to the dropout. Should have done that to start with, instead of directly to the dropout, but didn't think of it.

--Change the jockey wheel out for a wider pulley-style roller with raised edges to "channel" the chain between them, so it can't come off.
Started to do that before, when using it as a tensioner for the pedal chain, but did not actually make the roller. It would be a rollerblade wheel, notched on the lathe for a bit wider than the chain, then bolted into the brake arm on a hole drilled into it a little closer to the pivot. That's so I can keep the smaller threaded hole already in the end of it in case I need the arm for something else later, *and* to shorten the "length" required for the whole assembly, since the rollerblade wheel is at least three times the diameter of the jockey wheel, perhaps a bit more.

This is beginning to be close to the amount of work needed for the mounting plate redo, now, but I need to be able to make better chain tensioners anyway, since this type of arm will be used for my throttle at some point, and THAT has to be reliable, too. Might as well work it out now.



Speaking of throttle, I have to be pretty careful about how much power I give to this 4-pole motor. If I have the bike in a higher gear, say, 4th from top (of 21) or higher, and I'm at a dead stop or going fairly slow (9-10MPH), then if I push the throttle past maybe halfway, there's so much torque that it actually pops the chain over the teeth of the rear cassette sprockets! That's not good for the chain or the teeth, so I need to watch out and make *sure* I shift to lower gears before I slow down, even more than I did before.

The old motor, even with me cranking as hard as I can, could not do that--I never anticipated that as a possible problem.

I shortened the chain a few links to make it very tight on the largest front ring and the middle rear ring, just to see if it would help, but it doesn't. It still pops. Lots of torque!

I know the chain and the sprockets are both old. I'm probably going to borrow the newer chain and cassette off my regular bike (the DayGlo Avenger) to help alleviate some of this, as I suspect part of it is caused by wear, though much is simply the amount of torque available.

I'm also considering taking the front 3-ring set off the DGA to swap for the one on here, but if I do, I won't *have* a spare bike, as I have no other square-taper crank set I can put on the DGA. I could swap it out when I need to, I suppose, but I'd rather not have to do that sort of thing. The DGA set is larger diameter for all three rings, so it would give me back my 20MPH top speed (currently around 18MPH-ish max), if I calculated correctly, as well as having less wear on it than the smaller rings i'm using now. Plus, with the larger ring and more teeth, it'd have better power transfer into the chain (less strain on each tooth).


I also need to replace that damaged rear-shifter cable housing. That is preventing me from shifting properly, and sometimes doesnt' shift at all until I move it several stops over from whereever it was.

Then I need to fix the front shifter. I'm tempted to just take it off, and manually move it from ring to ring whenever I need to shift for hills, since it is so rare to need to do this. Almost always I am on the largest front ring, and shifting thru the entire range of rear rings.


Another thing I'm seriously considering is to separate the pedal and motor drivetrains, running the motor to the left side, and having just a three-speed motor sprocket selection (a three speed hub would make this very easy, as long as it has no freewheel built in).

This would simplify some things, and complicate others.

I find that typically, even before the shifting problem came up, I would use the lowest or next to lowest rear chainring, then somewhere in the middle, then the highest. If I can just use a 3-ring setup off the front of a regular one-piece BB, and it's shifter, I could make a left-side shifter for the motor drivetrain. I just have to make sure it has ratios for the right road speeds.

That takes away some of the hill-climbing ability, though, in that even this motor will heat up more unless I can shift to higher motor speeds for lower wheel speeds but more wheel torque.

It does make it easier by far for me to use the regen capability of the controller, but only if I can also make a clutch of some type to disengage the motor entirely for coasting.

It also means I will have two completely independent drivetrains, with the rear wheel being the only common point. I have an idea about that, too, using a variation of my "dualie wheel" idea, where two rims are laced onto one hub, for two tubes/tires (for less worry about having flats in back where it's really hard to deal with on the road). As long as one tire and rim is ok, then even a bent rim or blown tire won't stop me, and with two tires/rims taking the load back there, I'd have less likelihood of bending rims in the first place. :)

Look Ma, No Pedals!

While discussing the pedal chain problem with someone else, it suddenly occured to me that it could actually be the frame twisting, which was not really possible before due to the multiple triangles of the center frame, which no longer exist. A tensioner should still fix that, but there can't be *much* twisting happening, as I can't feel or see it, so that tells me the chain is on the edge of coming off all the time even *without* this problem. :-(


Speaking of chains, I just tied the chain up out of the way for all of my riding to and from work today, and it worked ok. However, I don't get nearly the speeds I think I should be getting; I think the 12A shunt analog ammeter might be restricting the current flow, or I might have a poor connection somewhere (probably with the wires from the battery pack to the meter, quite possibly in the crimp connections to the spades for plugging into the back of the meter).

That's easy to check, by bypassing the meter at the pack, just bolting the two wires back together again.


Now, I know it'll be slower with the 24" vs 26" for the same gear, but this is more drastic than that. Maybe 3-4MPH less than before. According to this calculator:
http://www.sheldonbrown.com/gears/
it shouldn't be more than at most 1.5MPH difference, not even that, for top speed in highest gears.

Also, I think the rear brakes might be flopping back and forth touching the wheel, slowing it down in bursts, because when cruising I can watch the ammeter fluctuate by a couple of amps or more, with a period of less than a second, which I think is about what a wheel rev ought to be, especially since as I slow down I can watch the oscillation slow as well. It doesn't always happen, but there's enough noise on the road including the motor noise that I can't really hear sounds well enough from the back of the bike to hear if something is rubbing.

So between those possible problems, both of which are still awaiting confirmation, I guess it could be robbing me of enough power to cause this.


A completely random thought regarding the name and looks of the bike:
I am seriously considering a mutation of the CrazyBike into the Junkyard Wolf, with "fairing" that would look like a wolf leaping/running, with it's legs over the front wheel in a kind of pounce position, rear legs astride the rear wheel as if having just leapt into the air. Head would be right where the lighting is now. Then my seat would end up just over the curved back.

I think a prototype version of this look is in order first, and then when I rebuild the bike "from scratch" to improve all the many things that need it from this prototype, I can make a better more permanent version of the "wolf fairing".

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.

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.

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).

The Sound Of Silence

The bike isn't really silent, because of all the chain noise and whatnot, but it's reasonably quiet. I'm hoping to reduce a lot of the noise by freewheeling the motor and pedals separately from each other, and finding some way of keeping the bike frame itself from being an echo chamber inside the tubes (without trying to fill them with sprayfoam or something, as tempting as that would be to try, I'm sure it'd be a mistake).

I know that the frame itself is amplifying some of the noises, because it really cut down on some of the noise when I isolated the motor from the frame with that rubber pad--the chain noise on the motor's gearbox output ring was being conducted thru the gearbox body into the bike; now that noise is only conducted a little thru the rubber pad, and thru the chain itself to the receiver ring and then the rear BB via it's shaft.

I wish there was a way to isolate the shafts themselves from the bike, but the only way I can think of involves using the sealed-bearing type shafts, which I don't have, inside larger-than-usual BB shells, with something like nylon or rubber lining the shells to prevent metal-to-metal transmission of sound on the BB's and crankshafts.

Because of the even and constant way the load works on the rear BB it would probably work ok, but on the front BB with the pedals on it the load varies as the cranks rotate around via pressure from my legs, and pushes first on one side then the other. That means that the nylon or rubber would be giving way then pressing back on each side during a crank cycle, causing any pedal action to have an amount of wasted energy in recompressing the nylon/rubber each cycle, and also causing wear and cracking of the nylon/rubber over time.

So I'd have to only do it on the rear BB. Since that's where both drivetrains come together with the rear one, it's the one where the most energy turns to vibration and goes into the frame anyway, so it should help the most.

The best way to have a larger BB shell is to use one meant for the one-piece cranks, which fortunately I actually have a frame for one that's a lot like the Schwinn I'm using right now--I could pretty easily modify it to bolt right on where the Schwinn frame is, if I had both the nylon or rubber tubes and the sealed-bearing square-taper crankshaft. But I don't yet have either of the latter, so the idea is just here on the blog as a thought for later testing if I ever get those things.

Pedal Freewheel Mk 2.5

Now I am nearly done making my pedal freewheel. Just the adapter to bolt the chainring to the freewheel is left, and deciding if I want to weld, braze, or JBWeld the freewheel adapter to the crank.

I really don't think JBWeld would hold up, based on past attempts at using it for stuff like this. It just can't take the twisting loads and shear forces like that.

So here's the basic adapter:

The rightside bottom bracket bearing cup is press-fit onto the carefully-filed (but still not perfectly round or centered) crank arm, at the shaft end. Then the freewheel is threaded onto it backwards from the way it would go on a rear wheel, since now it's on the left side of the bike, and has to ratchet in the opposite direction.

Once it's threaded fully on, then the lockring from the BB bearing cup is threaded onto it, and tightened down to ensure the freewheel will not unthread itself with the force of pedalling, since the threads are the same direction as the unscrewing forces would be from the forces on the chainring/freewheel against the crank.

I wanted to round off the crank arm's axle end on the lathe, but the arm is too long to fit above the bed, and moving the bed upwards and securing it so it would not move with the high loads placed on it by the swinging crank arm in it's jaws proved impossible with the things I have here. It just moved too much with each rotation, and would have come loose from the bed (very bad).

If I had something like a pottery wheel with a centerbolt, I could've used that to do it, but I don't, and the time it would take to create something similar is too great right now, even though I could use it for many things later.

I had some 1/8" hard aluminum (dunno what alloy) from scrapped custom-made test fixtures, so I chose that to make the chainring adapter plate since I can more precisely work with it than with steel.

I first clamped down the chainring in question to the surface of the aluminum plate, then used a drywall screw to score around the edges of it as needed to mark where I will need to cut and drill to attach it and clear the teeth, etc. Then I determined the center of it, and used the only hole saw I have (about 1/4" smaller than the freewheel's rim, unfortunately) to bore the center hole. I also drilled out the six chainring mounting holes using the plastic chainring spacer as a guide to mark them first.

The adapter will be the same diameter as the plastic spacer, partly to act as a chain guard for the sprocket (I have had two pairs of pants "eaten" by the chain on this in high winds so far, even though I had the second pair tucked into the sock!). It's also so that I can use it to bolt to larger chainrings should that be desireable later on, without making a new adapter.

The plastic spacer will be used between the adapter and the chainring, just as it was between this chainring and the larger one that actually connected to the spider/crank on the cottered cranks it came off of.

More or less, this is what it might look like if I also use the chainguard that came with it (except that the adapter plate will of course be cut out round).

This is the set of parts for it, including the cottered crank the chainring and plastic spacer came from.

Mostly what's left is to cut out the adapter plate from it's source plate, then get that plate on the lathe (probably using the larger cottered ring bolted to it, minus the crank, so that I can clamp it in the chuck jaws), and then lathe out the center hole to be perfectly round and centered, and as good a fit as I can get on the freewheel. First I have to put the lathe back together, and I was way too overheated and oversunned today to do that.

Then I drill holes near the inner edge to line up with the tooth gaps, and bolt that adapter to the freewheel's teeth. Then I can play with spacing if needed, so it will fit the space between the crank and the BB. Might require some filing away of BB bearing cup hex head on this adapter assembly, but shouldn't take much. It fits perfectly on the right side, but I need it on the left side, which has a BB cup that sticks out a tad farther.

Then all that's left is that brazing/welding decision. I don't have stuff to braze with, but I know someone that does, and I will ask if he will do it or let me use his stuff to do it. Welding I can do here very easily, but I am not confident that I can keep from destroying the threads with spatter or warping if i do it that way, even if I could mask it off somehow.

I am so close; it would be great to not have to windmill my feet to keep up with the motor driving the pedals when I choose not to pedal but want to run the motor for these tests (or later in the winter when I know my knees will hurt a lot worse than they do now).

Also so that I can then come up with a regen-braking-capable shiftable drivetrain for the motor side of things, that won't feed back into the pedals.

Pedal Freewheel Mk2

I discovered that I don't have the right parts or tools to do this as I had thought I could at the end of the last Pedal Freewheel post. All the screws, bolts, or threaded rods I have that are long enough and thin enough to be welded to the inside face of the crank arm's core don't have any nuts that will fit! Anything I have nuts for is either too short or too large a diameter.

Worse, however, is that I forgot about the face of the BB bearing cup/nut, which sticks out far enough that despite having that small clearance, only has it because it is smaller diameter than the inside face of the freewheel/etc. So I could fit the plate, but not the boltheads or nuts, thus the idea is unworkable with anything I have on hand.

All is not lost, however, because I had a fortuitous accidental discovery. As I was dejectedly spinning the freewheel and hub piece around on the BB spindle first one way and then the other, the threads on the freewheel engaged the threads on the BB bearing cup!

They are the same diameter, threading, etc!

I pulled out the only "spare" BB bearing cup I have, and it happens to be the same diameter, and it is wide(deep) enough to give full-width support to the freewheel (unlike the hub, which only engages about half of the FW's threaded width). The bearing cup is 30mm inside diameter, just a bit smaller than the outside of the crank's core, so if I lathe the outside of the crank to match that, it'd slip right over and everything would fit perfectly. But if I lathe it down, it'll just be a slip-fit (even if it's a tight one), and would almost certainly come off or just spin in place once I really lean into the cranks on hills and whatnot if I ever have to.

Since I don't want to weld the cup to the crank, I can use splines to transfer the power. If I either just file away the unwanted diameter of the crank in places I don't want splines to be, and then file corresponding notches in the cup's flat cylindrical surface (the part that doesn't actually get used inside the BB) to the ridges on the crank, then it should transfer power well enough without further attachment. Given the hardness of the metal on both pieces, I'll probably have to use the Dremel for the majority of the work, and then file to get squared edges/corners later, or it'll take weeks to make. :)

The only catch is that the bearing cup has no outer retaining ring built into it, and I don't think the locking ringnut that normally goes onto it on the BB will fit here, unless I grind off the hexnut outer portion of it used to tighten it into the BB. I'd rather not modify it in any way I can't reverse, since I may need to use this part on the next version of this bike, what with not having been able to get any more scrapped bikes for a long time now.

So I *could* weld a couple of tabs across the flat outside of the hexnut area, and later grind them off if necessary to reuse it for it's normal application.

Or I could drill a hole laterally thru a couple of the hex nut's faces, then press fit a pin into that that would protrude just enough to prevent the freewheel from unthreading itself beyond the edge of that face. I have several pins that are just long enough for that, removed from the wheelchair motors' power-brake-lock that I am not using on the bike. This is probably what I will do, assuming any of my drill bits are hard enough to make it thru the bearing cup's hardened metal (probably not).

So I think I have a solution, and will ponder it overnight in case something else crops up that kills the idea or I get a better one.


EDIT: I've found that (naturally) what I discovered is already known to others, as exampled in this thread on Endless Sphere, and this thread too.

Regen vs Freewheeling

Now that I am adding a freewheel to the pedal cranks, I'm seriously considering disabling the freewheel in the rear wheel cassette, so that I can get regen on the motor, and use the motor itself to help brake the bike, as well as recover a small amount of power.

I would probably also want to put a kind of clutch into the motor drivetrain, so that I could still coast on flats or down slight grades without running the motor but also without triggering regen braking. It'd be of a type that is electrically controlled, and on all the time except when I trigger the "cruise" mode to free it up.

I considered the clutch from the air conditioner compressor in the parts Ford LTD, but that operates the opposite way I want it to--only engaged when power is applied. Maybe I can reverse that, but I'd have to take it apart first to see how it works as-is.

Disabling the freewheel shouldn't be that hard, but I don't want to do it in a permanent way if I can avoid it; most likely I will have to simply sacrifice the freewheel permanently to the experiment, and weld it together.

I have a number of them around, but only the one on the bike has 7 chainrings on it (except for the free*hub* that's on the DayGlo Avenger) , and I don't think they'll fit on any of the others that have 5 or 6. So for the experiment I would have to use one of the 6-ring units, and simply not have all the available gears I've got now. Not too big a deal with the motor on there, but having more gear ratio choices is certainly helpful for pedalling should I need to do solely that at some point.

Pedal Freewheel

Rather than the foot pegs, I decided to add a freewheel at the pedal chainrings. Now, these things exist already, but I've never even physically seen a bike with them (only pictures). There have been DIY ones before, some of them doing something a bit like what I'm doing, but they were on the right side of the bike, which would make it easier. My pedal chain is on the left side, so it's tougher.

If I had a steel crank on the drivetrain input I'd do this back there, instead, which would again make it easier. But it's aluminum, swaged to the steel chainrings, so I'm afraid if I weld there, I'll destroy (or at least weaken) the swage to the crank which would make the whole system fail, since the motor input is also there. At least if the pedal output section fails during testing this idea, it will only leave me unable to pedal, but the motor would still work. Redundancy. :)

The pic below shows the parts used:

The crank without a chainring on it already will be used for this, so I can leave the other chainring intact in case of failure, and swap them back while on the road if I have to. I've done a little shaping of the area around the square-taper hole to better fit the freewheel/adapter, and to ensure clearance with the bottom bracket of the adapter later on. Hopefully it hasn't weakened it too much, but only time will tell.

The freewheel on the right is a fixed-gear freewheel, to which I'll bolt a chainring with as close to 43 teeth as I can find in my stuff, to match the 43-tooth ring on the other crank I'd just been using. The freewheel is threaded all the way thru from one side to the other, so it can be flipped over to use it in reverse of the normal action or be used on the other side of something.

The left half of a rear hub that's sitting near the crank is the unused part; I only need the ring with the freewheel threads on it, in the bottom part of the pic.

That bit will have the freewheel threaded onto it, then will be welded to the crank.

The other bit there is what's left of the bearing cup/race from inside the threaded section of the hub, which is in the way of doing what I need it to do.

This is a pic of just those latter two parts.

I would *prefer* to weld the former spoke-hole ring to the crank, but if I do that, the threads will be facing the wrong way, and then it will unscrew itself as I pedal. That's why I wish I could do this on the receiving end of the pedal chain; if I had more steel square-taper cranks I could.

This is pretty much what it will look like when attached:

That's a view as if you were looking *thru* the bottom bracket at the inside of the crank.

An oblique-ish view:

A "top" view, showing the spacing.

There will be about 1-2mm between the outermost part of the BB cup threads/nut/etc and the innermost edge of this adapter, once the crank is tightened back down.

The real catch is the welding on of the adapter to the crank. I'm afraid it will end up warping the threads, or damaging the freewheel. The threads might be irrelevant, because once it's welded on the freewheel can no longer be removed anyway, without cutting the adapter off.

What I might end up doing is welding it on by the spoke ring anyway, even though it could unthread. Then use a tack weld across the threads to the adapter and the freewheel to hold the freewheel in place against pedalling forces (which it probably wont' actually do if I had to pedal full force without the motor, but since I'll only be pedalling if I absolutely have to for these tests, and only minimally, it should be ok.

I can still dremel out the tack weld and unthread the freewheel if necessary (for instance, if it breaks).


But I'd rather figure out another way. Perhaps loctite or something similar. Probably insufficient.

There is a possibility that I could weld pair of small bolt to the crank itself, to either side of the square-taper hole, then use those to bolt a plate against the inner edge of the freewheel that would then prevent the freewheel from unthreading itself. It's the most repairable solution, but I am not sure I can find bolts small enough to fit.

To Pedal or Not to Pedal

I think for a little while, I'm going to bolt on some foot pegs in front of the seat on the bottom edge of the frame, so my toes are just behind where the pedals circle around (they move when the motor runs), so that I can do some serious hard-testing of the system without any pedal input at all, and be sure that I don't "help" the system by unrealizingly pedalling (since I'm so used to it).

I'd like to test it to breaking if it's going to, while I am on shorter trips that aren't time-sensitive (so I can pedal home with all that weight if I have to).

The end result of the system will be to have a pedal-assist that *requires* some pedalling, but not a lot, but at the moment I am more interested in breaking all the stuff I can before I rely on it. ;-)

Power Levels and Motors and Noise

I found the battery specs:
http://www.sacredsun.com/product/sacredsun_product.asp?series=ssp

Naturally, they don't list any model matching these exactly, as they show an SSP12-18, but these are SSP12-17. Close enough to base any assumptions about it's specs on, though.

On the battery that died in last post's ride, I took a look under the barely-glued-on strip covering the rubber vent caps, and I am going to try adding drops of water into it's cells to see if I can revive it. I mean, I can't hurt it any worse than it already is, right? ;-)

I'm sort of thinking about trying the bike out at 48V, since that (with 4x 12V 17Ah) would have about the same energy density as two of the larger 12V 31Ah U1s as a 24V pack, but should theoretically take a lot less current to get the same torque/speed out of it. That means the batteries would last even longer, because the Peukert effect that causes batteries to supply less total power the faster the power is sucked out of them would apply less.

The motor appears able to handle it, as I don't see any more sparking on the brushes at 36V than 24V when I watch it in the dark, so I will probably test it with one of the motors I've got pulled apart right now (the one that had the grease leak).

I wanted to use that 4pole motor on the bike but so far hadn't found any bolts in my stuff that would fit it, except for carriage bolts, which don't have a shaped head on them to turn, just a round-stud end, and a several-inch-long machine bolt with threads only on the first inch or so, which means if I cut it to make it fit without several inches of washers stacked on it, it won't have any threads. And I only had the two total, and need four--two short, even two inches would be fine, maybe less, plus two longer, perhaps 3 inches.

I found some good short machine bolts that will work for the short end of the 4pole motor mount plate. I'll weld a nut to the head end of a carriage bolt and use that to tighten down the long-bolt end of it. 3 bolts should be able to hold it at least for testing. If I find a second carriage bolt I'll use two. I'm sure I have several just like this one, in a box somewhere. I *really* want to see what this motor can do. :)

I could definitely do this higher voltage stuff with the treadmill motor, and I'm still pondering a drop-in drivetrain and motor plate that would let me put the treadmill motor on in place of the wheelchair motor without modifying that bottom plate any further, and would come off and go on as quickly and easily as the wheelchair motors do (which is one thing I really like about them).

One thing I *don't* like about them is that they're pretty noisy. I fixed a little of that by putting a rubber pad between the motor and the bike frame's mounting plate, but noise is still conducted thru the bolts, and I don't have a long enough set of them to use a pad on the bolt side, too, with fender washers and whatnot to keep things from sliding around against that chain tension. The pad itself came out of an old dead Macintosh Plus, from what looks like an optional harddisk bay I didn't have in mine back when I still had it working, a decade or two ago. At least, I don't remember it.

The treadmill motor by itself is a lot quieter, but I suspect most drivetrains I make for it are going to add significant noise, just because I'm not great at machining the parts and mounts for things, so nothing lines up exactly right.

One problem I have is that none of the crank-mounted chainring sets are perfectly round. The rings might be round but if so they're offset a little from center, so there can be as much as 1/8" or more difference in distance from center to edge from one extreme to the other, which means the chain gets tighter and looser and causes more wear and also more noise. Since the teeth aren't 1:1, it also means that as they rotate around they offset their rotation, so the tighter/looser pattern changes over time.

Not only does this cause noise, but it is going to make my tension-based throttle system impractical until I can fix it. As I watch that spring-loaded throttle arm roll over the chain, it goes up and down by almost 1/3 of it's full travel, with no load on the chain at all except this tighter/looser rotation pattern!

I'm not even sure I *can* fix it, because, for instance, the chainring on the drivetrain input is steel swaged to the aluminum crank/squaretaper socket. If the offset is there, I can do nothing about it. If the offset is due to a bent BB spindle/crankshaft (possible but highly unlikely) I can't fix that either, because I dont' have an extra.

For the front chainring, it's not only offset circumferentially, it's also bent around the entire gainring rim just a little bit here and there, so the edges appear to "wobble", making it rub more on the sides of the chain at some point than others (and possibly one day under the right conditions to even lift the chain off the ring, if the teeth ever catch an edge of the chain). It did not start out this bad, so I think the little bending it already had is being made worse by the very high tension forces on it as I pedal hard during startup from a dead stop without a motor on there. Shouldn't worsen more if that's true, now that I have the motor back on.

What I need to fix that is newer and/or better-made square-taper cranksets with the chainring sets on them. What I would *like* if I could pick and choose is a handful of the *same kind* of crank spiders, plus the chainrings that go on them in a good variation of sizes. Then I could pick and choose my ratios, and they'd be stiff enough to not have to worry about this offset and bending happening, hopefully.