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Old 06-30-08, 01:26 PM   #1
adamtki
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Anyone experience a front wheel wobble?

I changed my front tire to a thin one and noticed a wobble (about 4x per second) at any speed when my hands aren't on the handle bar. I can even notice something was off when my hand was on the handle bar. Seems to be related to how rear heavy my electric bicycle is compared to the front. The front tire came from a road bike and of course, i don't experience any wobble or shimmy when my road bike has the tire. Do any of you have this sort of wobble since I would imagine most of your electric bikes are rear heavy? Anyone have a better explanation for this?
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Old 06-30-08, 02:10 PM   #2
Oshawaebiker
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I think the sidewalls of the tire are collapsing under the weight causing tire roll. This is one reason for using a wider tire on e-bikes. May not be as efficient but is more stable.
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Old 06-30-08, 03:00 PM   #3
adamtki
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I'm 150 and my e-bike is 50lbs. There are lots of 200 lbs road cyclists out there. My rear tire which is on the motor wheel is a 700x32c at 80 psi. That should be plenty of tire pressure for the rear. The front wheel is 700x25c which should be good too. I estimate that e-bike's weight distribution (without rider) is 15 lbs in the front and 35 lbs in the back.
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Old 07-04-08, 04:42 AM   #4
donob08
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Quote:
Originally Posted by adamtki View Post
I changed my front tire to a thin one and noticed a wobble (about 4x per second) at any speed when my hands aren't on the handle bar. I can even notice something was off when my hand was on the handle bar. Seems to be related to how rear heavy my electric bicycle is compared to the front. The front tire came from a road bike and of course, i don't experience any wobble or shimmy when my road bike has the tire. Do any of you have this sort of wobble since I would imagine most of your electric bikes are rear heavy? Anyone have a better explanation for this?
Adam, it's hard to understand how anything rotating can cause a vibration/wobble at a constant frequency independent of its frequency of rotation. If you put the old wheel back, do you still sense the wobble?
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Old 07-05-08, 02:20 AM   #5
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I should clarify my "at any speed" statement. I didn't clearly state it but I meant that it wobbles at any speed (not that it wobbles at 4x at any speed).

Discovered my rear wheel has a long cut in it. Any deeper and the inner tube would've burst through. I had to replace the wheel. At the same time, I switched back to a different thin wheel (lent the other thin wheel to a friend). I think the bulge in the rear wheel from that cut caused the wobbling. Maybe it wasn't enough to make a noticeable effect with thicker front tires.

Anyway, if it happens again, I'll post an update, but for now, it appears solved. Thanks.
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