I don't know if it's possible to do this with an actual Xtracycle due to it's frame construction, but I am pondering an Xtracycle-like addon (that will do this) to that Schwinn Sierra I fixed up recently, perhaps with a motor assist, perhaps not.
Specifically so that I am not dealing with a longer shiftline and the problems reported with it where shifting can be finicky in one gear or another, I intend to put a regular rear hub with the derailer still on the Schwinn's dropouts, so the original chainline stays as it is, as does the shifter cable. Then there will be a separate sprocket from that hub to the rear wheel, which will be re-laced to a no-dish single-speed wheel to make it stronger for cargo use. (actually I will probably just take a front wheel with a sprocket bolted to it, for simplicity of testing out the idea).
I will probably build the addon frame around an existing rear triangle off of some other bike. I am tempted to use the one off the white Huffy, simply because it is called a "Nevada", which would make this bike a "Sierra-Nevada". ;-)
But that is a silly reason to pick a frame, so I will more likely start with one of the old chromoly tenspeeds I have, whose frames are way too tall for me to use for myself normally. I'd remove the entire rear triangle from the donor frame, but not including it's BB. I would cut down the seatpost from the bottom end, leaving that extra on the BB itself. Then reweld the seatpost and chainstays to a new crosstube from something else. This would all be welded to a subframe that can then bolt to the Schwinn Sierra's rear frame and keep the whole rear end stiff. It would mount in such a way as to leave a clear chain path between the Sierra's rear dropouts and the new rear wheel position, and would be able to slide back and forth for chain tension adjustment and lock in place to hold it once set.
I would like to make some bottom/side rails that let me rest cargo on them (like some Xtracycles do) that are removable, so I do not have to carry them for typical rides, but instead only when I will carry more than normal stuff with me.
Then a top deck to cover the entire space from over the rear wheel to the back of the seat.
I am also considering a more recumbent seat design that would fit down into the gap that could exist between the tire of the new rear triangle and the Sierra's seatpost/seatstays. Then I would move the steering handlebars back to fit in a bushing in the seatpost, and a linkage for remote steering to a stub-bar up in the original stem. This is a very similar arrangement to Justin's (of http://ebike.ca) cross-Canada bike, and inspired by it.
The problem with such a design is that it reduces the cargo I could carry on it, so I would (as Justin did) likely leave the option of pulling off the remote steering and inserting the original seat and post, and riding it just like that. The 'bent seat would stay, as it would make a nice carrier for some cargo. Well, unless the cargo was too large and needed to fit across the full length of the area behind the seatpost.
Just some thoughts for another possible cargo bike, most likely quite short range in nature.
Wednesday, January 20, 2010
I don't know if it's possible to do this with an actual Xtracycle due to it's frame construction, but I am pondering an Xtracycle-like addon (that will do this) to that Schwinn Sierra I fixed up recently, perhaps with a motor assist, perhaps not.
Sunday, January 17, 2010
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!
Friday, January 15, 2010
spinningmagnets on ES is looking out for internally-geared hubs, which would greatly simplify the switching-gears on the front wheels, and ought to be able to take the nominally 300-350W per wheel I would be putting thru them, as long as I set it up to cut power during shifting.
So I will probably build the front setups simply using regular rear hubs on both front wheels, and any multi-gear drivetrain I come up with for temporary use will be easily removable. I still need a ratio change of around 1:5 to get the 20MPH top speed, from the gearbox output that's intended to directly drive wheels half the size of the ones I'm using for 8MPH.
I have been pondering a way to swap the gears in the gearboxes so that they output closer to what I want to start with. I cannot remember exactly what ratios they are inside for which parts, but basically the main reduction is from the motor shaft's helical gear to the first right-angle gear in the box. Then that has another gear on the same shaft that meshes with the output gear, which is on a lever-type clutch to disengage the gearbox for manually pushing the wheelchairs these came from. I'm pretty sure that the last two gears are different sizes, with the larger of the two on the output shaft.
If the shaft diameters are the same between the output shaft and the first shaft, I can swap the gears so the larger one is on the first shaft, which will give me some amount of anti-reduction (gain?) within the gearbox itself. If they're not the same ID but I have or can make a collar adapter for the difference, I can still use the gears swapped; just have to lathe out the smaller one to fit.
Then I have just that much less anti-reduction to do from the gearbox to the wheels. If the gears are the same OD/teeth or the larger is already on the first shaft, I'll have to do all the work outside the gearbox.
I've also considered taking the motors off the gearboxes and affixing a timing-type pulley directly to the motor shaft but this would require creating a drive-end plate for the motor that supported the shaft, as right now that bearing is part of the gearbox. This is not that trivial a matter to do, for me.
I would then need a much larger pulley on the wheel itself. I can't recall offhand the motor RPM, but somewhere in the 3000 range, I think. That would be a ratio of about 9:1. The smallest belt pulley I have around here is for a V-groove, and it's around 1.5". So I'd need a 13.5" diameter pulley on the wheel!
I can't recall the way to figure minimum number of teeth I'd need engaged for a timing pulley, but I suspect it'd be at least an inch or two in diameter.
Can't really use chain; at 3000RPM at the motor end that would be a helluva noise.
Basically, at 9:1 reduction, compared to 1:5 anti-reduction, I'm better off sticking with the gearboxes and using bike chain/sprockets for output shaft to wheel transmission. It's not as "efficient" as less stages of changing ratios around would be, and it's heavier, but it is a lot easier to do, with less stuff I have to build from scratch to make it work.
Now, one problem I have is that for the right side wheel, to get power from the motor to the wheel, I need the motor on the right side of the wheel, just like it will be on the left side wheel. But that would be problematic for reasons of safety, clearance, and keeping the motor itself safe from damage. So the motor must go on the left side of the right side wheel.
That leaves the issue of how to get power to it. To use a regular bike hub for it isn't that big a deal, as I can just bolt a sprocket (or weld it) to the left side of the hub. But I will want to use the internally-geared hubs for this later, and those will need the sprocket on the right side of the hub. Meaning I have to get power around the wheel somehow.
Thus, I will probably end up using an extra hub at the rear of the fork, to act as a jackshaft and pass motor power thru to the other side of the wheel. I can simply use a front hub since I don't need to put any freewheels on there, or spoke a wheel to it, and just bolt the sprockets on thru drilled-out spoke holes if they line up right. An adapter plate if they don't. Or weld them on, one on each end.
I just weld on some little dropout tabs to the fork near the U end of it, just clear of the wheel.
For the fork itself, I'm going to need to take some 24" or 26" U-forks, and cut them in half at the stem end. Then weld a tube across there to space them far enough apart for a rear hub to fit in the dropouts up front. But since the internally-geared hubs need dropouts that are slotted to fit them, and I will need enough dropout length to use to adjust chain tension (no derailers), I'll need to remove the original dropouts and put on some from scratch or from BMX bike frames.
Alternately, I can just build the forks from scratch, which would simplify making them significantly, and give me control over every part of their design, as well as make them the same for each side, mirrored. (well, mostly)
Another thing I've been pondering, and that is which way to make the forks--vertical or horizontal.
Horizontal will keep more weight down low, which is very good for a trike. But it means the motor mounted on there will have to have it's weight swung back and forth on the pivot every time I turn, which will act as a pendulum weight and make steering a tad more difficult--it will tend to resist starting to change the wheels direction, and resist stopping that change, too.
Vertical will essentially fix the latter, but will place at least a little more weight up higher. I can still mount the motor itself so that it is centered about the axle, and that will keep most of it's weight low, but the fork will still be higher up and that weight will be above the centerline, giving the trike just that much more susceptibility to tipping in turns, especially if I use the kingpins/pivots up at the top end of the forks.
If I mount the motor vertically on a horizontal fork, it will end up as the best compromise, but it will interfere with the steering pivots and kingpins, unless I move it farther forward, and then the pendulum problem reappears.
Probably I will go with the horizontal fork, and change it if it doesn't work out right.
I've been going back to my old trike research and rereading info I found then but didn't apparently fully comprehend at the time. Now I have seen enough stuff in action and worked with various things in steering, and I understand them better. I think if I had built a trike before, unless I had simply copied someone else's design, I would have ended up with an unsafe or unrideable trike. :( Now I think I know enough to make a passable first shot at it. ;)
I am certain that I got lucky with CrazyBike2, in that it's configuration ended up working fantastically well for something so randomly chosen at each point in the process. I'm fairly good at the by-guess-and-by-gosh process, but it doesn't always work. :roll: The trike needs more thought put into it, and more choices of parts based on design rather than just whatever I have laying around. That said, I think I have a handle on it, and might be able to start building it in a month or so. Less if I'm lucky enough to figure the rest of the design out sooner.
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.
Not much progress here yet. Still trying to find enough time to test the cells, sort them, and then find a good way to assemble the packs.
A new problem with doing it is that the Sorenson I had been using to charge the batteries on CrazyBike2 before, and was going to use to charge up the NiMH packs (from deardancer) and test and charge the Li cells with, just sparked and smoked when I turned it on last night, even though it wasn't connected to any load yet. It's a linear supply, and does not require an external load to operate, so something must've died in it during power-on-surge. A transistor burned and a resistor smoked, and a couple of traces on the board's cardedge connector vaporised, too.
I've got three others (only 40V models) that are not working for various reasons, so I will need to check their boards for the values of parts, and then see if I can trace out enough of the circuit to ensure replacing the blown parts is all that will be needed, so I don't smoke more stuff when I turn it back on again. :roll:
Maybe I'll get the others fixed while I'm at it. :)
I did have another idea for charging the NiMH, though: I already had two little NiMH chargers for AA batteries, and I found another for a couple bucks at a thrift store, so now I could charge up to twelve cells at a time. All three chargers will charge either two or four cells at once. They are all microcontrollers or dedicated chip chargers, so they should be safe to use with any NiMH cells.
I am considering putting charging taps on every cell in the NiMH packs, in connectors of four cells, and one of two cells. Then put a mating connector wired to the contacts on each little charger so I could not only plug in to these cells, I could also still use them for the AA and AAA cells I already use them for (for my flashlights/headlights/taillights, etc. on the non-ebikes).
Then I would be able to charge three sets of cells in the packs at a time. On the 36V pack, that's 30 cells, so two charge cycles for 6 of the 7.5 sets in it, and one more charge cycle for the other set plus 2 cells. On the 24V pack that's 20 cells, so only two charge cycles total (one for 3 of the sets, and one for the 2 full and 1 half set).
The whole pack will not get that warm this way, and though I will have to manually plug and unplug the charging connectors after each cycle, it will let me safely charge the packs.
Well, assuming I don't burn out the chargers doing it; they only put out less than 500mA charge current. Well, one of them can put out almost an amp charging current if it's only charging two cells. I'll try it out with the cheap thrift store one first. It's the model down from one I already had, and is an Olympus BC-100.
I'm also considering taking a bunch of old celphones I have that are broken in various ways, and wiring them up to charge cells. They're all isolated from each other, so I could theoretically charge the pack "in place", with charging taps coming out of it for each cell, and a charging connector. It would never be a fast charge, but it would be possible, though a lot of work.
I would need to take the little BMS board off each celphone battery, and lay them all out on something flat. Then solder wires from the cell connection tabs to the interconnect that would go to my pack cells. More wires from each board's input connection tabs to the celphones themselves.
If I have enough celphones that actually give me a display (many have broken screens or even broken-off flip tops) then I can even monitor the charging process via the little battery meter on the displays. Not much of a meter, but better than nothing. :)
Tuesday, January 12, 2010
A little redrawing needed. I found the article by Julian Edgar I had been thinking of that explained this stuff, which reminded me of a few things.
The "steering inclination angle" for scrub radius is indeed pointing at the center*line* of the tire, but not the contact patch itself. I still need to have caster (trail) so it needs to point ahead of the contact patch. ;)
I also came up with a couple of possible ways to add the motors to the front wheels, but I am thinking I might want to have shiftable gears, at least two of them, since I end up in stop-and-go traffic often enough to make the power usage horrible, since it will use a lot more current at slower speeds if it's geared high enough for 20MPH.
Apologies for the incoherence of the sketches; I did them while eating dinner since I had the ideas in the middle of that. So they're not pretty. Later they'll be translated into Sketchup if worthwhile.
One issue I have is that i need to get about 5:1 gearing if I use only 24V to drive each motor, because they were originally designed to drive a 10" wheel at 8MPH. To get a 20" wheel up to 20MPH, I need 5 times the output RPM from the motor. On CrazyBike2, that's partly acheived by running it at 36V (now 48V), and partly by the bike drivetrain. Plus, the motor on there runs about 200RPM at 24V IIRC, and these only run about 135RPM or less. So it is a challenge either way, if I use a series wiring setup as the electrical equivalent to a "differential".
One of the ideas uses rear triangles on the front, with the old style one-piece cranks for the triple, and a 5-speed cassette on the back. Only the back gets a derailer, because the triple isn't used for shifting, just as a jackshaft. The left side triangle keeps it's triple. Only a single large ring will be used on the right side's triangle instead of a triple, with a granny ring welded on to the left end of the shaft.
The motor would bolt to a bracket fixed to the triangle in a way that leaves it below the chainstays (for COG reasons) and on the "inside" of whichever side it's on. On the left side wheel it's on the right side of the stays, so that the chainring mounted on the axle hub will be lined up with the granny ring of the triple. The right side wheel will have the motor on the left side of the stays, running to the welded-on granny. The large ring of either side will run to the wheel, shiftable to each of the cassette rings by the derailer. Both derailers would be operated at the same time, by a ganged shifter setup.
Has to be a ganged setup so I can properly adjust each derailer for shifting, while still shifting at as close to the same time as possible. Will also have to shift while not under load, cutting throttle way back during the shift, so that I don't end up being pulled back and forth on the road by the difference in speed while one wheel is shifted but the other is not.
I fully expect this to be too complex to pull off well, so an alternative is to use the regular front fork, and set up the wheelchair motors themselves as if they were the bottom bracket with two rings and a front derailer. This would require putting the U of the fork in front of the wheel instead of behind, and might require putting the righthand motor on the outside of the wheel, which I don't want to do.
Now, I know the reports on the internally-geared hubs under motor power aren't good, but if I used one for each wheel, and ensured no shifting under load and no sudden starts, I might get away with using them. This would make it a LOT simpler to use these wheelchair motors and gearboxes to drive the front wheels. Ganging their shifters would present the only real challenge. Besides actually acquiring two identical ones as part of scrapped bikes, that is. ;)
If I don't use a shiftable transmission, then I can go with a simple chain and ring, but I will probably have to use a two-stage to do it, due to the large ratio required, with the largest ring on the motor, and the smallest on the wheel, with an intermediate jackshaft making the second stage. I could do a 48 to 21 first stage, and another 48 to 21 second stage. Alternately, a 48 to 16 first stage, and 34 or 32 to 16 second stage, to keep stuff a little smaller with a little less chain weight.
Any way I do it, I will need to widen the U forks to accomodate a regular freewheeling cassette, even if I only use one of the rings on it, with no shifter.
The original thought before i realized the ratio needed was just to use a belt and pulleys:
The tank style steering:
More later as I think of it.
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.
Monday, January 11, 2010
More parts donated, including a lever for my throttle
That is in the max output (max pot reading, 5K) position.
That is in the max physical pot rotation position.
That is at the zero pot position, centered on the pot (the pot, like the lever, is made for a reversing motor controller in a wheelchair).
I don't yet have the spring return on it, as I need to make something to connect from the throttle lever into the spring's "catch" for the return action. Should just need a little bracket to wrap around the far end of the lever's pivot and back in an L shape into the spring's "catch".
and some interesting actuated "gas" (probably hydraulic) springs.
The springs are neat because they have a little push rod in the center of the strut, which must be pushed in before the strut can move. This is done for ride-height adjustments on the chairs they come from (using a cable and lever similar to bike brake levers but smaller), but the nice bit about this feature for me is that they would let me "disable" the spring action if the bike was too heavily loaded to work without bottoming out, simply by raising the lockout lever.
Or they could be used solely for their ride-height adjustment ability, and not as springs at all. That would let me explore different front and rear heights to see what worked out better for height for clearance of road debris, curbs, etc, vs stability in turns, before permanently building that height into the frame (if ever).
Day before yesterday while helping a friend move stuff, I scored a couple of nice but very beat up bikes that happen to have square taper cranks with several things I have wished I had for a while: bolt-on spider/chainrings for the triples, trigger shifters, and some good derailers/shifters for 6-speed cassettes.
One is a larger triple than the other, and I think it is aluminum or some alloy for the rings (as well as the spider/crank. I can actually wiggle it side to side between spider legs.
The other triple is much harder, does not wiggle, and has that darker brownish tinge of titanium, although I am sure it is just plated or anodized to that color rather than actually being made of titanium. I sure wish it was, as I doubt I could break it if it was. ;) The crank/spider is still aluminum/alloy, which is fine. It's a lot smaller rings though, so I'll need to use the smaller ring on the motor, maybe even cut it off and replace with an even smaller one.
The crank rings on the Trek do appear to be very hard metal on the largest ring--it does not even have it's tooth count stamped in it as the two smaller rings (of a different color metal) do. It is stickered as a Shimano Hyperdrive C. It's a 42T, and the others are 34 and 24. There is minor damage (chipping?) on certain teeth and tips, but it is in better shape than most of the rings I already have around here.
Being a Hyperdrive C tells me more certainly that the original wheel/cassette isn't on the back, because AFAIK these were meant for an 11T rear smallest sprocket.
The rings on the Schwinn are larger, at 48T, 38T, 28T, but are definitely weaker than the Hyperdrive rings.
I am going to see if I can work out a new driveline on CB2 for the motor/pedals using the Hyperglide as the receiver. Kind of a waste, as it won't be used for any shifting. :)
I will probably just put the old strong single-ring cranks back on CB2's pedals.
There are a number of other nifty parts on the bikes, too, including even the frames, which appear to be nice cromoly, and are light enough I can pick them up onehanded even with the whole bike together, though I can't carry them far (I'm a wimp and my knees and joints hurt a lot).
One has Shimano trigger shifters, but they weren't working. The trigger shifters are part of the brake lever mounts, too. The cap on one is missing; hopefully it is only a cover and not a functional part.
These may end up being perfect shifters for the trike, since I will not have my hands in my field of vision with the tank style underseat steering, so I also can't see what gear things are in or what position the shifter lever is in. A trigger shifter always returns back to "home" after each shift, so it would be easier to shift with "blind". In theory. I've never used one.
I did a little bit of cleaning of the trigger shifters, and now they work fine. Just had dirt in there keeping the mechanism from moving the ratchet. I'll have to make a cover for the right (rear) shifter, or that will continue to be a bad problem.
The other has Deore lever shifters for a 6-speed rear cassette and a front triple, which is what I have on the CrazyBike2 right now. The Deore shifter I have on CB2 is for an 8-speed and thus doesn't shift properly due to differnet ring spacing (I dont' have anything with an 8-speed cassette).
Both shifter cable housings were disintegrated at the shifters, as you can see.
One uses vbrakes, one uses side-pull linears with the noodle. The vbrakes appear to be almost new pads, the others have some medium wear on them.
There is only one good tire on there, a Kenda something-or-other. The others are typical knobby stuff, though one of them is much less so than the others.
The Schwinn is a non-suspension bike, and the Trek is a hardtail with front shock forks that don't appear to work. They are labeled Skareb, though parts of the lettering are worn off so I can't read everything on it.
They appeared to be hydraulic rather than spring, but turned out once I found the manual online to be pneumatic shock and hydraulic damping. There is a lever on the top of one of them that I originally thought was supposed to adjust the ride/travel and thought was missing on the other one, but it turns out to be the damping adjust, and is only supposed to have one.
The other is a schrader valve, which I aired up to about 100PSI based on the manual and some posts found on an MTB forum, and it now operates as a shock. :) I haven't opened it up to check the oil, but I suspect it's empty or near so (or the valves are bad) as there is no damping at all, regardless of the red knob setting.
It appears based on the manual to be easy to disassemble to check it out and/or fix, once I have time to clear off a table to lay out all the (presumably oily) parts. :)
One bike has wide-flanged hubs, which could come in handy for bolting diskc brakes to via adapters, but neither has any disk brake mounting holes on the hubs. The shock fork above has the mounting for the brake calipers, though. They're all 26" wheels with aluminum rims and hubs. Don't know if the spokes are good ones or not. I'd bet they are better than the cheap junk on most of the wheels I have.
Turns out the rear hubs on both are regular freewheels, and I suspect they are not the original cassettes, either, as neither one even has much in the way of the little shifting-helper-ridges and contours on any of the sprockets--they're pretty much flat on the Trek, and just have the twisted tips on the Schwinn.
The rear hub of the Schwinn:
The hubs/rims on the Schwinn could be original, they appear to be at least decent quality ones and both match. Spokes seem a lot better steel than the Trek, as they don't just bend (even the loose ones) with finger pressure. There is a spot on the rear rim that is dented/bowed out a little from what was probably running over a rock (there's no matching one on the other side, so not likely a pothole or curb jump). They're even reasonably true.
I'm pretty sure they're not the original rims on the Trek, as the rear is a VERY cheap steel rim that has a horrible welded seam, with cheap steel spokes on it. The front wheel isn't that much better but is at least intact. Neither is true at all.
The Trek is really a mishmash of different bikes, and some of them were very badly put together, including it's rear hub. I thought maybe it was just loose, and jokingly thought it might be missing the bearings, as it was so wobbly. Actually it was missing the cone nut, and a regular washer had been put against the bearings, with NO LUBRICATION AT ALL, with a single spacer-style nut tightly up against it. Regular nuts just threaded there as spacers up to the dropouts, but not threaded up to the washer very hard. This was the result:
Yes, that is a flat-sided bearing, and it's not the only one.
All the bearings are actually stuck to the race so hard I can't pry them out; I suspect they're partly welded in place by friction heating. It even looks like the bearing cup itself is separated from the hub's outer edge, and pushed into the wheel some.
This is all on the drive side, so the stress broke the spoke you see above, and damaged others.
Sunday, January 10, 2010
So now for some concept images, created in Google Sketchup mostly using existing bike parts from things found in their 3D warehouse.
The wheels are 20", for visual scale. The main tube is 2.5" O.D.
The side view looks a little long. I am not sure if it will need to be this long or not yet.
There's no detail to anything yet as I am still working out positions, angles, etc.
The top view makes it easier to see the camber of the wheels, which is 7.2 degrees in the drawing but I don't yet know what it has to be in reality. It just "looked right".
The wheel supports angle back because that is the direction of pressure in a turn and it is also the direction I would want it to angle to during shock absorption if I ever get that far.
Front view shows camber clearly. The green bits are the Razor scooter headstocks.
I intend to have the line thru the headstock it pivots around point directly at the tire contact patch. If I understand how steering should work, that should give no scrubbing of the wheel during a turn, for better traction. I am not *certain*, but I do not think trail matters much in the case of a tadpole trike, based on the way I see it working in my head. Thus, there is no trail on this steering setup.
An iso view.
The steering pivots are behind the wheel pointing forward and outward at the contact patch. It is possible I will have to make it point forward of the patch instead.
Saturday, January 9, 2010
Now that it has a smart-ass moniker better than the last bike, lets see about getting the design together. :) Sorry there are not a lot of pics yet, still working out the design ideas in my head.
It's based partly on Lee's most recent trike from The Packrat Workshop, after some conversations with him about what might be best adaptable to the parts I have on hand. So it likely won't have suspension, at least in front, for this version.
It'll be a single-tube main frame, probably made from a 2.5" fencepost I have.
That galvanized post with the mangled right end, within the L of square tubing, is the one.
One possible way it could be configured, but probably won't be:
Depending on length of things I might use this instead:
with the load-wheel tubing cut off, at the far right, and most of the mast up top cut off.
That will go back to a bottom bracket pivot point for any rear suspension. I will probably not have a spring/shock for it by the time I need to ride it, so it will end up with just a solid tube bolted in place of whatever shock I would have used. I still want to build the pivot into it now, though, so it can be much more easily suspended later. :)
The rear triangle will be a modified one off of a 24 bike, probably off the old Roadmaster frame I originally started to use for CrazyBike2's rear end, but swapped out for the much lighter and slightly longer Schwinn frame instead. The main modification will be to make it vertically shorter, by cutting the seat tube down and bending the seatstays to meet it at the much shorter location. Rather like the back end of CB2 already is. This is mainly so that the entire triangle will be "below the deck" of the cargo pods that will run alongside it. Probably a 24" wheel, too, since the best slick tire I have is for that size.
Those pods will be the pods off CB2, mounted on a frame very like the one CB2 has, except that it will all be hanging from the back of the main tube, not connected to the rear triangle. Thus all the cargo pods will be suspended with the rest of the bike frame.
The seat will need to be built from scratch, and will be a lot like the one on CB2, but more form-fitting, if i can bend the tubing this time. I'll be again using tubing off an old bedside potty chair, same as on CB2, since it is small-diameter and extremely strong. The webbing will probably be the same green stuff I used on CB2's seat, simply because I have more of it and it's lasted just fine for more than half a year so far. It'll be tensioned using the same parachute cord lacing I used for CB2.
Like Lee's trike, I'll use tank-style steering, as it's mechanically simple and easy to build. It also doesn't take much space for it's movements, and won't get in the way of getting up and out of it like handlebars would, nor will it get in the way of my leg strokes for pedalling while turning, as can occasionally happen with CB2's bars at extreme turns with my kneecaps. :(
Pedals will be over the main tube and out beyond the front wheel axle, though probably not beyond the whole front wheel. Not completely sure until I finish the 3D sketches of it how the alignment works out.
The front end is where things get different. Because I am going to be forced onto sidewalks sometimes by either traffic or ignorant law-enforcement personnel, I can't make it wider than the sidewalk. Since a number of bike paths have protection poles across them to prevent cars from driving onto them, and those are generally spaced wide enough for wheelchairs, the front end will be no wider than a wheelchair.
Some of the parts I am considering for it:
Each front wheel will have it's own non-hub motor, most likely a wheelchair motor with it's reduction gearbox, with a V-pulley on the output shaft and another V-pulley on the wheel hub. The gearboxes have a tubular indentation in the top of the mounting plate, which happens to be the same as the steering tubes on a couple of the 26" forks I have.
So one idea is to clamp the motor to the steering tube, and setup the pulley on the hub and shaft so that they'll line up just outside the tire's sidewall.
The motor would then stick out to the rear of the wheel, parallel to the ground.
It is just one mounting idea, but one that happens to involve the least modification to the fork to do it. There are some serious disadvantages to it, too.
Then another steering tube is welded to the inside-leg of the fork down nearer to the dropout on the side opposite the pulley, at an angle that gives me whatever camber/caster turns out best for this thing (I still have to work out enough of it to then be able to figure out how to calculate that out).
That steering tube will then go into the headstock off a Razor kick scooter. Those things are meant to fold, so a few inches away from the headtube is a pivot point in the square tubing. That headstock is then bolted thru it's original folding pivot point to the end of a square tube welded at a forward/sideways angle out from the main tube, like a very wide Y. Another pivot point is welded to the headtube above that, which will go at first just to another tube welded to a vertical mast on the main tube.
Later, part of that horizontal tube will probably be replaced with a suspension of some sort, which is why I want the pivot point there now. If I don't end up putting suspension there, I would like to still end up making some sort of four-bar-linkage so I can make this a tilting trike, to improve stability in tighter turns at speed.
As heavy as each wheel will be, that means that the front end should be fairly stable in turns anyway.
To add to that stability, the SLA batteries (probably 4x 12V 17Ah) will be slung underneath the front end and the seat. That should help keep the weight to 1/3 on each wheel of the trike, but I will need to actually measure everything once I get it mostly designed, to make proper placements for things.
There will be cargo pods up front, too; I don't know what their shape is yet as I am not certain what spacing I will have up there.
Behind the seat on it's rear brace will be a vertical post sticking up to windshield level on the average car. A box will be mounted atop that with front, rear, and side lighting appropriate to the direction it faces. There will also be separate lights at the outermost corners of the cargo pods in the rear and the forks up front, for markers, signals, and emergency flashers. I don't yet have a set of lights to put on here, so I will probably be custom-building them. The lenses will likely be made from various bike reflectors glued together, with LED (for any flashing lights) and CFL (for any steady lights) lighting behind them.
Brakes will probably be disk brakes, donated by the very generous AussieJester. I have to fabricate adapters for them, and thus will probably be using some 48-spoke rear hubs I have on some 48-spoke 20-inch rims. The rear hubs are freewheel threaded on the right, but I will flip them over to put that on the left side, and make disc adapters out of something already threaded to that. I might be able to use the bottom bracket tube from an old cottered-crank frame I have, if the threads are the same pitch and the correct handedness. Then weld the tube to plates, face them on the lathe, and drill boltholes to match the disks. Basically they would do the same thing as these.
If I can come up with the cash, I'd rather order a couple of these from Choppers US, as they'd also make mounting the pulleys much easier, too, since they're made for dual-disk, one on each side.
It would also mean I could have both discs on the inside or both on the outside of the wheels, rather than both on the left side, which results in the left wheel's brake on the outside and the right wheel's on the inside. I don't imagine it would make a difference in performance to be the latter way, but it might make fabricating the forks a little harder since they won't be identical nor mirror images.
The catch is those dual-disk hubs are 36-hole, and I really want to use the 48-spoke wheels to help more with the side-loads and weight on this thing.
That's it for the moment, until I can get some pics of parts I have and some 3D sketches done up. Or at least some pencil versions scanned in.
Now, hopefully [i]this[/i] little guy won't get shot in the head when I do the trench run. :roll:
Sunday, January 3, 2010
Actually, not so much evil, as just insufficient to handle the job on this bike. :( But first, some info and pics of the things I did to fix recent problems....
Considering what I started with, I decided to use an older less damaged wheel to redo. The pic below is of the one damaged almost three weeks ago. The bent axle is pretty clear
and you can even still see the rim bending a little, though I straightened it A LOT just to get it round and flat enough to roll down the road to get home.
The spoke hole damage is what forces me to change rims entirely:
Its' very bad, and holes all around the rim on the drive side are like that
where they started out flat/flush. None was actually pulled *out* of the rim, nor were any broken, but it's bad. I have not taken the cassette off to examine the hub. I just went ahead and redid the wheel using the old Roadmaster wheel that was last bent by a pothole (I think), and replaced it's bent axle with one from one of the Christmas parts bikes, and used a cassette from the other one.
An overview pic of the repaired bike (after today's failures but you can't see them in this pic):
I rode around the neighborhood for around 4 miles testing stuff out without any problems, coming back to the house after every little loop to check things, tie wires down, etc, as I made sure each thing worked.
The newly built wheel, using the stainless spokes. They seem to be doing better than previous ones, as I do not get the wheel flex I used to with the old thinner (and probably cheap steel) spokes that had been in that rim, when I turn, etc.
After a few miles the wheel needs semifinal truing (and will probably need it once more after a few more miles, as the spokes settle in).
The tire is not yet aired up in the pics above, which were taken with the bike upside down but camera held that way, too. :)
This is a chain deflector made to help hold the pedal chain about a millimeter away from the motor chain, as it intersects with it near the receiver rings, so they don't rub anymore.
It's made of a piece of my sister's discarded plastic cutting board (either teflon or nylon, don't know which but it works either way).
The clearance is VERY narrow.
I also decided to do the same where the pedal chain crosses under the motor hub axle, as sometimes in left turns the chain would rub and even catch.
Now it is MUCH quieter, meaning that it was rubbing against the motor chain a little bit even when it did not seem to be, and now is rubbing against the plastic but not making the little ticking sounds I could sometimes hear.
The clearance is a couple of millimeters.
The front brake really wasn't sufficient before, or wasnt' working well, not sure which. It had been a linear side-pull style, with the little metal noodle and all to redirect it to vertical. Now it is a set of center-pull, again off one of those parts bikes.
They're cheap brakes and I don't like them much. But they work better. Not good enough, but better. The hard part was that they require something external to the brake unit to push the cable housing against. Normally, that is a bracket that is part of the U of the fork, but that wasn't possible on this shock fork, or else pulling the brakes just compresses the shock, rather than braking!
The shock fork on that other bike has the bit built as part of the U, but that whole fork is flimsy--I can twist it with my hand, unlike this one, so I don't trust it on this heavy bike.
So I took a little black steel rackmount ear tab and bolted it to the brakemount/reflector hole on the U, then used a seatpost-mount tab for this style of brake off another bike, bolted sideways thru the rackmount ear upper hole. The bike cable housing is then pushing against the fork thru this, and it works very well with no visible flex.
It is still not enough braking power, and I still need something like disc brakes (possibly in addition to the rim brakes), once I can figure out how to design some, if I don't run across any on something scrapped out.
Another addition is a Stanley Tripod Flashlight. It's a Freecycle find, and was described as not working. Indeed it did not, when I got it, but a quick check inside found that one of the power wires to the LED board was never even soldered. The wire ran thru the hole, and there was hotglue from the factory to hold the wires down, but they missed soldering this one. Easily fixed, and voila!
For now it's just zip tied to my existing light.
It was daylight when I took the pics (noonish), so I don't yet have pics of it in the dark. I will have a separate post for it later. But it has a very good beam, though not nearly bright enough for most street use. For canal path or unlit roads, it would be fine, but where there are other light sources shutting down my eyes' ability to open up the iris, it's not enough to help very far away.
It lights up street signs EXCELLENTLY, though, when it is aimed high. Aimed normally, it'll show me the holes in the road fairly well at 20-30 feet.
Don't know battery life yet; it runs on 3AA batteries, and can have a set in each leg. Right now I have two sets of NiMH in there in parallel, one 2000mAh and one 2300mAh. The third leg holds a set of regular Duracell AAAs, with a piece of plastic keeping them from being used at the same time as the much lower voltage NiMHs. If the others die, I can take one out of each leg and pull the plastic out of the Duracell leg, and use them. Only doing this now because I don't know the lifespan of the light yet, and don't want it to suddenly die on me.
Once I figure out what the electronics driving the LED are, I may change it out for a brighter one I have, if they will handle the current it needs to draw and can be modified to do so.
As the Curtis is a 48V capable controller, I decided to also add the fourth battery:
For now it's just secured in the righthand cargo pod, until I can tell if it makes a difference. I have not yet wired in the chargers. This battery is wired in as the "top" of the pack.
While I was at it, I also wired the lights into the monitoring circuit, so the Turnigy meter can tell me about their usage. So far it takes about 350mA to run the CFLs at 48V, including the laptop adapter used as a DC-DC converter. It's only a little less on 36V. Turn signals take the same 2A-ish peak, dropping way down pretty quickly as they blink each time. The LED brake light is about 300mA by itself.
The curtis itself is mounted on the side. Even during a test where I put the front of the bike against a wall, and ran the motor at about half throttle, hard enough to spin the wheel in the dirt if I didn't lean on the bike, it didn't get even warm for the few minutes of the test. The motor itself warmed up quite a bit.
So either the Curtis is holding the heat inside due to the electrically-insulative pad it uses between the inside heatsinks and the case, or it simply isn't getting warm enough to notice.
The main keyswitch is this:
glued down into the top of the steering tube the handlebars mount to. Horizontal is off, and vertical is on. Have to turn it off to take the key out.
Since things fail, and I might need to reach it fast, I also wired this in series with the keyswitch:
It's the run switch from the old Honda scooter. I left the handgrip (throttle) off of the assembly, and just used it for the knob and the brake handle (and built-in weatherproof brake light switch).
Center is run, and up or down turns it off. Can be flicked with my thumb if needed.
Ideally I'd like to take the brake switches and wire them to a DPDT relay. One pole would be NC for the motor run line, in series with the keyswitch and the run/stop switch. The other would be NO for the brake lights themselves. It's just something I have to "get around to".
Mounted on the bottom/inside of that is the throttle pot. It's shown without the lever here for reasons best explained in a picture farther down.
Until I fab the other metal bracket for it, it's screwed in securely to the grip body on one end, and ziptie-clamped to the handlebars on the other end. It won't move in normal operation.
The lever runs parallel to the grip, so I can push it down with my thumb. To fully grab the brake handle requires letting go of the throttle, making it not quite impossible to power the motor while brakes are on, at least with the front brake and this hand. I could still do it using the rear brake and my left hand, of course, which is why I want to do the brake-cut-off relay.
But first, I have to makea new throttle pot clamp:
It's metal, not plastic, but it broke like plastic.
I can only assume I must have somehow tightened the set screws on it too much, although I am not sure how that would break it like this, something did. It came apart as I lightly pressed on it after I got home, so at least it didn't cause me a problem on the road. Since the spring return is done by pressing against this black piece, if it had happened on the road it would have left the throttle "stuck" in the last position, requiring that I manually grip the shaft and turn it.
Now for the ugly part. :(
Less than a mile or so into my trip, another of those half-second-to-destroy-things failures happened, again with the chain derailing, but this one was caused by my fiddling with what had been perfect alignment, in order to fix the pedal speed problem (having to pedal really painfully fast to help the motor at any high speeds), and the pedal-chain looseness problem due to being a half-link too long or short, because of tooth count on the pedal chainring.
I thought it was perfect this time, but apparently not. What basically happened was the motor chain derailed to the left of the motor receiver ring, got caught between the ring and the outer guard of the ring, which being not only metal but actually part of the crank spider meant that it was strong enough to then force the ring inward slightly.
The teeth on that ring must've caught the outer edge of the pedal chain, which then was pulled onto it, bending it in even further since like the motor chain it has no slack.
Then it bent the pedal ring outward, and the bike STOPPED. That all happened so fast I didnt' have time to prevent it, just like the other disasters of this type.
Fortunately the pedal ring is a 3-ring set now, so I was able to take the extra link back out of the pedal chain, put it on the middle ring, bend the motor ring back out of the way, set the rear drivetrain to the front granny ring, and pedal my way the rest of the way to work and then home later.
So I guess it's time to
A) make solid steel chainrings to use with the spiders (have to find some of my scrap plate steel of the right thickness, print a drill pattern from the computer and glue it on, then drill it out, file it, and then harden it somehow).
B) find a way to ensure perfect alignment. I don't really know how to do that, as I was SURE it was aligned already, and it worked for almost 5 miles with zero problems, then suddenly BLAM.
Nothing shifted around or is loose, either, even under motor tension, that I can see, but I know conditions while moving on the road are different.
Either way, I'm guessing it's getting time for CrazyBike3, 1000-mile mark or not. :(