Does torque arm design make a difference?

[Icemaker]

I think I understand the benefits of the brushless motor with running cooler & smoother.

The only part I dont really get is the torque arm?
People on the forum are always saying " that's a nice torque arm setup" etc."
Are there EV bike makers that have bad torque arms?
Is it really an important part & do they break or make a hub motor break or spin?
I had problems with my heinzmann, as the wires feeding thru crushed in the torque arm When I tightened it.
I had a lot of problems getting the wires right so that they didn't short out.
Thanks

 

[el_walto]

Any torque arm is better than no torque arm.
Yes some torque arms are made stronger(thicker) than others.

You should find the thread where Justin tests different torque arms in different situations.

 

[dogman dan]

I have 3 kinds of torque arm laying around at the moment.
The worst, is thin steel and might just cut a groove in the axle instead of stopping rotation. It also has no adjustablility, and so it may only fit one fork design.

Better is the one from Ebikekit. It has a pivioting arm that makes it able to fit most steel forks and it's nice and thick.

Better still is the newest design from Ebikes-ca. Also nice and thick, it's pivot point has even more adjustablility that allowed it to fit on a DH grade alloy front fork. Without this torque arm, I couldn't have risked mounting a front hub on an expensive suspension fork.

Best I ever saw though is on the heinzmann motors. This design is completely different, and uses a much much bigger axle and bearing. This allows tons of room to pass the wires into the motor, and also allows the tourqe arm to fit into the axle instead of over the outside. A normal hub motor has about 10mm of bearing surface on the flat of the axle for the torque arm to grab. On the heinzmann, there is perhaps 25 mm of bearing surface. This allows the heinzmann to have a normal diameter axle that is round, so everything fits normaly on the bike dropouts. The heinzmann design solves all the problems beautifully.

 

[Carzy]

Justin did a bunch of torque arm tests here, useful reading...

http://endless-sphere.com/forums/viewtopic.php?f=2&t=14195

 

[grindz145]

There are ENDLESS threads here with torn dropouts. The higher you go the more important the torque arm is. They're necessary.

 

[dogman dan]

You bet. The question is though, which ones work, and which are decorative accessories, and at what power levels do ones that work become decorative.

It seems to me, that at some point, a clamping dropout custom made is the only answer untill they redesign hub motors to be more similar to the heinzmann ones.

The only other approach would be a thick steel torqe arm or torque plate that bolts on to the frame as a substitute for a dropout. But for now bikes are made to be bikes, while we are turning em into motorcycles. Not a good situation once we cross the 1000 watt line.