[Shotimes] Vibration or picky...again

[Zach Leahy]

Just a thoght,

i didn't hear the whole story here, but i you wailed a pothole ard
enough, there is a slight (albeit quite slight0 chance that you bent
the lug studs.

I give that about a .000001% chance of being correct, but what they
hey e are all fising here.

Z


On Thu, 17 Feb 2005 17:12:15 -0500, Leigh Smith <leighsm@comcast.net> wrote:
> Well;
> This is getting tough. Good thing I like brain-teasers!
> OK - Belts can shift in a tire, for many reasons, sometimes just due to
> curing /heat issues. Many symptoms. Tread could move laterally 1/2 in or
> more, or it could get a bubble in the tread or sidewall, or it just may have
> a "stiff" spot during rotation. (Old BFG tire employee / chemist / racer).
> But your car vibrates with 3 different sets, so I'd rule all that out.
> Same with 3 sets of rims - rule that out.
> Now we are down to rotor / hub issues.
> I'm betting your problem is in there some-where.
> It's not bearings, different symptoms.
> I have no experience with Baer brakes. Are the calipers solidly mounted? or
> do they float on pins?
> You mentioned a slight scrape during rotation - this usually happens with
> even minor variations in rotor thickness. However, yours doesn't vibrate on
> the brakes, so I'd rule out any major issue..
> You mentioned hub/rotor runout. I'd measure the hub VERY carefully, with
> machinists type tools, dial indicator, solidly mounted, etc. Runout should
> be almost zero.
> If you have solid mounted calipers, I don't see how hub or rotor runout
> could be bad, 'cause the brakes would vibrate like mad.
> But if they float, like stock ones, it will tolerate being "out" a little
> bit.
> My best guess would be a slightly tweaked / bent hub 'cause of that pothole
> you mentioned. If it bent a rim, that was a pretty big shot.
> If that part is OK, then it must be the rotors. Not warped but maybe the
> balance is off. I'd have the rotors re-finished, and find a place that can
> dynamically balance them..
> George's on-car balance method, or the on-car machines that people used to
> use, would correct for that as well, but if you ever removed / rotated
> tires, you would have to have it re-done.
> You could put the tire back on the same wheel if you kept track of how it
> was "indexed", ie: which stud/hole.
> Sorry this was so long, but it is a tough one.
> Good luck!
> Lee
> 
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