> About a month ago I replaced the 48-spoke wheels with 60-spoke wheels &
> new Michelin XAS tires. The overall road-feel & handling is much
> improved -- my very shaky front end now feels much more solid. But, now
> I'm getting a strong vibration that I feel through the seat at about
> 70MPH (3500 RPM, the speedometer reads closer to 80). I tried swapping
> the front & rear tires, one side at a time, but it doesn't seem to move.
> It seems most noticeable while accelerating; when I take my foot off the
> gas, it disappears. Any ideas?
I'd be looking at the driveline, especially U-joints. Make sure the yokes lie
in the same plane as sometimes people disassemble the splined joint & don't get
it back together right. Also look carefully at the cups for the U-joint
bearings, if they show any signs of having moved (like a clean area around the
clip) then replace the joint. Also check that the bolts at each flange are
tight. As Chris K. recently suggested, I strongly suggest replacing the nyloc
nuts with metal interference nuts, like a Stover nut. See
http://www.mcmaster.com/ and search for P/N 92501A430 or P/N 91839A135 to see
some examples.
Randall
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