Torque Arm Derailleur Mount
- Thread starter hias9
- Start date
Chalo
100 TW
hias9 said:
I wouldn't worry about the thread. It's much, much more likely that trying to react motor torque through the derailleur hanger will bend the hanger or break it off completely. If you're going to anchor to something in that neighborhood, let it be the rack and fender eyelets.
hias9 said:Sorry, I forgot to mention that it does not have a derailleur hanger.
It's about 10mm thick cromoly steel.
It does not have rack/fender holes, but I am probably going to drill one.
Spec, for a mountain bike frame, of the distance between the center of the axle and derailleur hanger is about 30 mm or 1-3/16", which would be the length of the "arm". That's pretty short compared to an arm of maybe 3" length (76 mm), since the shorter arm would subject the anchor point to about 2.5x times as much force as the longer arm. You could do the math to determine what those forces would be, if you plug in the max torque of your motor (torque in N-m x 1000/30).
I might be more concerned if you were using regen, since that force would have the effect of trying to spread open the dropout.
If it's a road bike frame, the distance is about 15% shorter, so even more force will be applied to the anchor point.
DanGT86
100 kW
Isn't the hole in most frames a smooth bore with the threads being part of the hanger?
MadRhino
100 GW
You have enough surface around the dropout to drill and tap 2 screws to add a custom torque plate. Make one each side using 1/4 thick steel plate to cover the actual dropout plates, with the dropout slot longer for extra safety.
Yes, but this frame is thick cromoly steel and the hole has a M10 thread.DanGT86 said:
neptronix said:
I would definitely not rely on it itself. I am pulling almost 200 battery amps at 22S, so lots of torque. For the other side I am making a 10mm stainless steel IS2000 mount torque arm.
That is what I am probably going to do. I think one hole should be okay.MadRhino said:
markz
100 TW
Hose clamps and some free steel from behind a store. I like 1/4" steel, angle grinder cut to about 1" x 4", and a few hose clamps!
MadRhino
100 GW
One hole could let it move back and forth with torque/regen hits. I always use two, sometimes M6, or chainring bolts when I have enough room.E-HP said:
Your dropouts are thick and solid. Good to hold a lot of power with tight fit torque plates.
E-HP said:
It is not the only thing. There will be a IS2000 mount torque arm on the other side.
I plan to use three 8.8 M6 bolts.
Before I had two-part hose clamp TAs on both sides. It did the job, but the axle was moving a bit inside the dropout.
Would you use washers between the TA and the frame, so the paint will not be damaged?
Do you think it would move around with one bolt on the right side when there is a two bolt TA on the left side? When drilling two holes I think the inner nut on the inside could be a bit close to the chain, but it should work
dogman dan
1 PW
Your frame looks ideal for drilling a hole to bolt on half of the standard front torque arm.
like this. or make your own plate. one on each side. If a regular bolt can't hold it, neither can the metal of your frame. But nothing wrong with the idea of a grade 8 bolt, simply because it won't get its threads smushed when the bike bashes a rock on a trail.
like this. or make your own plate. one on each side. If a regular bolt can't hold it, neither can the metal of your frame. But nothing wrong with the idea of a grade 8 bolt, simply because it won't get its threads smushed when the bike bashes a rock on a trail.
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