Torque Arm Installation Help Needed for Sprint-26

[fbl100]

[edited heavily from the first post, so the first reply may not make much sense with the new post]

I've spent some time tonight trying to figure out a way to mount the ebikes.ca torque arm on my sprint-26 , and this is the best that I can come up with:

If the axle and joint are all tightened down really tight, and I screw a hose clamp around the area noted with the blue arrow, is that sufficient?

The other option is to put a spacer (~1/4") between the dropout and the torque arm. That would allow the bent part to clear the frame and the straight part would rest above the Inline image 1rim mount. The only problem is that it wouldn't be flush with the frame, there would be about a 1/8" gap. The second attached photo shows the alignment I'm talking about on the top.

Are either of these valid installations, and is one better than the other?

Thanks!

 

[RoadWrinkle]

Not really your typical drop outs for sure; welding bolt mounts on the lower horizontal frame bar would be better than attaching to the upper verticals. Might be worth a visit to your local weld shop for a custom.

 

[dogman dan]

It's alloy, so forget welding on it.

You do have a dilemma there. That's a really good example of the kind of rear end that's not ideal for mounting a motor.

I kind of like the top picture best. I'd be inclined to not use a hose clamp through that hole in the frame. I'd fabricate a small strip of metal bent into a u shape, then drill and bolt through the torque arm.

To do the bottom version, I'd get something to put in the gap between the torque arm and the frame. Like a small piece of stout hardwood, or even a small block of aluminum.

With torque arms, tight is right, the allowable slop is zero.

Best thing would be to manufacture your own torque plate for that dropout. Then you can pick which hole to bolt into. You'd first make metal shim blocks to fit tightly into the odd shaped holes, then drill a round hole through both shim and plate to bolt up with zero slop.

 

[dogman dan]

Looking at it more, have you tried fitting it the other way, to clamp the second piece to the lower stay?

 

[fbl100]

Justin from EBikes got back to me and said that either of the above pictured configurations will be just fine.