Torque arms from Ebikes-ca w new pictures

dogman dan

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May 17, 2008
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Las Cruces New Mexico USA
Since I was planning to install a motor on some alloy suspension forks, I recently ordered some c washers and torque arms from Ebikes-ca

Justin has just done a redesign on his torque arms. The hole in the pivot on the main piece is now a slot, and presumably will fit more types of forks with fender eylets. The clamp arm has many slots now, and two hose clamps are provided so you can really clamp the thing down. The piece on the axle is nice and thick, and beautifly cut somehow. Water jet, laser? Anyway it's made to very tight tolerances and fit my axle on the 9c motor beautifully. The provided hose clamps were intended for use on normal forks, so I had to go get some larger ones. No big deal, but something to be aware of before the stores close for the night.

I was trying to fit the motor on a Rock Shocks Dart 1 fork, and ran into all kinds of problems. To make a long story short,,, Paint was filed from dropouts and the axle fit in the drops, but it was a tight fit. An allen bolt on the bottom of the fork interfered with the torque arm, so a bit was ground off the arm. The fit was very tight between the forks, but I got it crammed in there. Once on the bike, I found I had put enough outward tweak on the dang forks to make em stop functioning. The tubes were rubbing so hard they wouldn't move. So the install proceeds later with another set of forks. These ones, from Insync, had no problem fitting the 9 c motor.

And on the other side, The fit is a bit different due to the disc brakes mount. Under the torque arms are c washers to fill the space inside the quick release cups. Never run a motor on front forks without a perfect fit of all the washers and nuts etc. Hiding a mistake behind a torqe arm is not acceptable. I chose to run two torque arms even on a moderate power motor to garauntee that the wheel stays on the bike if the forks should crack.



When installing a 14mm ebike motor axle on a 10 mm dropout, it is often required to file the dropout notch deeper by about 2 mm. This is to keep the center of the 14 mm axle located in the same spot as the 10 mm axle was before. Otherwise, you may have problems with the axle working loose from the fork.Dropout filed deeper.jpg

Here is the C washer in place, to fill the dropout. It is also advisable to use a spacer washer on the inside of the dropout. This will help with some types of motors with narrower axle shoulders. If a spacer washer is used on the inside, the axle shoulder will have to be filed shorter by the thickness of the washer. The alloy forks cannot be spread out, they must fit the width of the motor perfect. If not, the shocks will bind.View attachment 1

Now the torque arm is fitted to the fork. In this case only one hose clamp could be fitted, use two if you can. Tighten the nut between the two parts of the torque arm as much as you can.torque arm attached to fork tube.jpg
 
I wonder if anyone has tried welding two-piece torque arms together once they're adjusted properly... wouldn't this help make the assembly more rigid? Any small tendency for the axle to rotate would be turned directly into push or pull against the fork tube. I realize this should happen anyway, but some small amount of "give" at the bolted junction seems possible. Doing this might make the wheel a bit harder to remove but it looks worth testing, no?
 
Not sure the multiple slots for alternative clamp positions are necessary? Wouldn't the slot at the farthest end of the arm from the axle always be the best for mechanical advantage? Why go any shorter?
Just curious
tks
Lock
 
As you can see on this photo, I had dropouts interfering with using the other slots. So the best position for me was the last slot. The arm comes with two clamps, and idealy you'd use two clamps, helping to prevent the clamp from moving, like sliding down the fork as the arm rotates. I have felt for a long time that two clamps would be a good idea. I don't really know why, but I just like double everything. Construction work taught me never trust just one of anything.

Anyway, what Justin has done is redesign the arm so that it fits more different kinds of forks, front or rear. The new design accomodates multiple positions and clamp locations in case a disk mount or something is getting in the way.

I gave some thought to welding the two pieces, once fitted. But then I'd be stuck with a custom fit to one particular fork. I fool around with stuff too often for that I decided. Right now the plan is to run 9 c in the winter when slower is warm, and haull ass on the aotema in summer, racing home to the AC.
 
Bumped with new pics. I have not had any problems with the nut loosening so far. It's two years later. Power levels used are only 1200w, 48v 20 amps.

I'd think that tack welding the two pieces after they were fitted would be a good idea for higher power levels. Stronger attachments than a hose clamp too.
 
I've welded two piece torque arms together before. Works well. Mine got spread open because the dropout wasn't deep enough to hold the axle in place.
 
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