Help with torque arm (Welders needed, Dr Bass needed)

ashriram

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I am a newbie to ebikes and just acquired the following setup from Grin.

9C 2706
35A controller, 36V.

It is a steel fork; the bike is a KHS Flite 220 (road bike/commuter bike).

Step 1: (No Torque Arm, but with torque washer)
The wheel refuses to stay on my dropouts; even at 20% throttle I experienced spin-outs (without a torque arm). I did have a V2 torque arm from Grin; but the motor's thread was too coarse and the torque arm would not slide over.

The attached image is the drop outs after a couple of spin outs. The side which had beat up the fork more was the one where the motor wire comes out.

Step 2: (with Torque Arm).
This is where I am looking for advice.
What is the best long term solution? Dr Bass? can I weld it on to my fork.

Any suggestions for welders in the Burnaby area. Anyone from BCIT?
Anybody have a couple of Dr Bass' arms I can buy for front forks?

I do have torque arms from Grin; would they cut it?
I will be hauling back and forth from work everyday to Burnaby mountain and
need something that lends me confidence to replace my car.

PS: Can I continue to use this fork?

Regards

IMG_5681.JPG
 
Those fork tips are messed up.

If you solicit the help of a welder, consider having him transplant a pair of snug fitting open end wrenches in place of your damaged fork tips.

After multiple spinouts, the section of the axle that is engaged by the fork tips may be rounded and thus less able to resist being spun again.
 
Buy a new/used fork, and get some torque arms.

If you want to cheap out go to a metal place like Metal Supermarket that can cut your steel to the general dimension of the piece(s), then use a jig saw with metal cutting blade. You'd have to figure out how to attach it, so I'd suggest buying a fork that has lots of flat area around the drop out. You can also rent a stick welder from Hertz Equipment rental, or find a DIY Auto Repair Garage like one here in Calgary, AB called U-Wrench, next up is a muffler shop, or place an ad on Kijiji (Im sure there are some trade welders in need of extra cash). Another option is to find a Automotive Forum like for Jeeps or something, and ask there. The reason for that is they are more likely to have a welder to them and in the economic climate today, I am sure there are some wheelers out there in need of an extra $40. Then if all else fails, weld wrenches.

Vancouver (Burnaby)
604-293-1231
Vancouver (Burnaby) website

7755 Venture Street
Burnaby, BC, V5A 1T9
https://www.metalsupermarkets.com/store-finder/
 
First, I'd try what Chalo said above, or if you cannot get a welder to do that, then you could use a small sledgehammer and anvil or other hard surface (even a couple of big rocks if you have nothing else) to reshape the dropouts back to what they used to be like.

Keep in mind that the dropouts are much softer metal than a wrench would be, so by themselves they cannot deal with the torque on the axle, even with as little power as is in your setup.

The torque washer actually makes things worse, not better, because it gets more leverage to pry at the open end of the dropouts, or potentially doesn't even sit between the tips, since they are not deep enough (not made for an axle as big as the motors have). If the steel were strong enough (it isn't) then filing them to make them deeper would help (but won't here).

(I've used a setup very similar to what you have there on CrazyBike2 for the DeathRace back in 2011, I think it was, maybe 2010, and it had the same problems you do.
https://endless-sphere.com/forums/viewtopic.php?f=2&t=12500&start=75#p328389
file.php


In my case, the torque arm I had was not designed for the shape of fork I had and it didn't help.

Your Grin torque arms should work fine, as long as they are properly secured. There are a lot of pics and info on different setups in the Torque Arm Picture Thread, if you poke around for it. Should help you figure out the best way to set them up for your fork and motor.


ashriram said:
I do have torque arms from Grin; would they cut it?
Yes, as long as they are mounted correctly so they can't move. Since you have fender mounts you can probably use those to help secure them.
PS: Can I continue to use this fork?
Yes, as long as the tips are repaired one way or another.
 
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