My opinion, as if you needed an extra:adamsavage79 wrote: ↑Dec 17, 2017 5:34 pmOk ? That's for the rear.. I have a front wheel motor....motomech wrote: ↑Dec 17, 2017 5:19 pmhttp://www.ebikes.ca/shop/electric-bicy ... rm-v4.html
-I'd only consider mounting a low-powered geared-hub motor on a cheap suspension fork.
...and I have... many times.
But I've also added 1000W+ with regen braking on custom designed suspension forks, one of which I've been riding for 6 years now.
-cast metal (steel or aluminum) can be either the best or the worst thing ever and any flaws in the casting will fail catastrophically (as your fork did). I wouldn't trust any casting to support the kinds of forces heavy DD motors can generate, including just the added mass of the motor in a bicycle fork. Pinched tube forks are better for mounting motors... because you're guaranteed the tube was not cast !
Even properly installed torque arms won't solve the problem as you've presented it. They might delay the failure mode but won't prevent it,and that is the the dropouts are fashioned from cast instead of rolled (metal, whatever metal it is)
You didn't mention what power the controller could support (the elephant in this room) because you might not have had this failure with a 7A (250W) controller... maybe. There's still the question in my mind about the mass of the motor affecting the normal operation of the bicycle's suspension fork.
Yep, cheap headset bearings wear fast... On one of my contraptions I had to replace the headset bearings approximately every 6 months (about $1.50 from the LBS) , eventually replacing the fork when the steerer tube fatigued and expanded under the pressure of the threaded stem thingie.dogman dan wrote: ↑Dec 17, 2017 8:44 amSome will say no way a motor on alloy forks. I just say it has to be done perfect. Even then, you may have what I experienced, the fork will jack forward when the motor is on causing the fork to bind. So with some forks, you have to get off the throttle when you cross the RR tracks, or whatever. Otherwise the fork is pretty close to rigid.
I did many thousands of miles on alloy forks, and never broke a fork. But the motor pull did wear them out fast. Eventually most of them started to do that binding thing. Only the very expensive forks, or very cheap, did not bind eventually.
Had to pound the fork out of the headset tube with my favorite BSO tool, the three pound sledgehammer.
(afterwards welding a new headset tube to the frame because the damage I caused pounding out the steerer tube!)
After all this typing, bottom line:
get a rear motor or a more suitable fork