dogman wrote:Welll, as the saying goes it depends. An experienced guy with a good appreciation of the forces involved can run a 1000 w motor safely on alloy suspension forks. But a careless type, with an ignored warning is going to bust his ass, as your friend did. No torque arms, and no C washers, garanteed fail. There's a problem but it aint the fork.
I now have around 6-7000 miles on front hubs, using either cheap steel forks or alloy. Never screwed it up, and never had a problem. People thought I was crazy running a front hub on solid cromo forks at 3000 w. It worked great. At about 4000w though, things got shall we say, a bit touchy, and I crashed out of the race. The forks are still solid and good as new though, because I made proper use of the torque arms.
I really have no worries about my install of a front hub with 1200w on alloy, but I can't help but worry about anybody else doing it if they don't have lots of experience with hubmotors.
The execption to the rule is lame 250 watt motors, that would be unlikely to have a problem.
The key thing is this, don't span a cup in the forks with an oversize washer. You MUST have a spacer washer, such as a C washer, or the nut will put spreading force on the dropout, cracking it. This is why Justin made the C washers.
LI-ghtcycle wrote:A friend of mine forgot that both suspension and aluminum front forks are a bad thing with front hub motor and learned the hard way!
dogman wrote:Something to think about, whether the motor is front or rear. Say you pop a small jump, the motor starts spinning faster in the air. Then when you land, that's going to be a serious spike of torque.
Assuming the battery is located at the rear of the bike, you get a better weight distribution (as opposed to a typical front wheel drive).
Also, practically you get a two wheel drive (rear wheel pedaling and front wheel motor assistance). A two wheel drive is better for use on slippery surface because you get better handling (Just like a four wheel drive automobile). Another thing is that the front wheel motor assistance won't cause any unintended wheelies on sudden acceleration.
2WD drive definately has it's place, I.M.O.
For low-powered assist riding, my FWD has been great, no control problems at all.
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