wheel balance runs amuck overnight?

[adamnitti]

just took a little trip up the highway a bit to my chiropractor... at 80mph, i had the out of balance wheel shakes like crazy! the last time i drove it (yesterday), it wasn't half as bad although i've had a tiny shake at that speed for a while. the crazy thing is, it seemed back to normal (very minor shaking at 80) on the drive home. i looked to see if i lost a weight, but all of the weights seem to be in place. is it possible for a wheel balance to change dramatically in such a short period of time? or do you think my tires developed a temporary flat spot that was cured by the heat of highway driving?

i've got another set of fuchs on their way to my house with tires on already. i think i'm gonna throw them on the car and go get these wheels rebalanced.
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Adam Nitti
ajnitti@mindspring.com
www.adamnitti.com
'85 911 Carrera Coupe
PCA member, Peachstate region

[This message has been edited by adamnitti (edited 08-01-2001).]

[Early_S_Man]

Adam,

If you didn't throw a weight ... how about a patch of soft mud (or loose pea-sized gravel) you may have driven thru just before you parked the car the night before, which could have hardened overnight? Then, perhaps loosened/thrown during the 80 mph run, the problem cured itself when the last of the mud cleared itself during the drive home?

I've never heard of (or experienced) a true tire imbalance that 'cured' itself, or varied in degree from day to day, either!

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Warren Hall
1973 911S Targa

[R22tech]

Mine does the same thing occasionally. At 80 mph it has a slight shake in the steering wheel that goes away above 85 or under 80. Funny thing is-it only does it on 285. It's fine at those speeds on 400. Maybe it was just the road you were on. Mine could also be flat spots due to sitting in my garage. I try to eliminate this by parking it on 2 thick pieces of carpet-no idea if it works, don't know how to tell.

[cstreit]

Probably flat spots.. How hot you getting those tires the night before?! Har har

My car does this all the time. After it sits overnight it feels like the tires are out of balance until they warm up a bit then it goes away. They seem to take a set as they cool. They are Kuhmo Ectstas by the way. This sounds like the same thing you are feeling. I don't worry about it to much, just an annoyance.

[pbs911]

Isn't it possible that the wheel bearings could be heating up and expanding. Hence the shimmy stops as the bearing warm up. It seems difficult to believe the tire could get a temp flat spot by merely sitting over night. Especially considering these are street tires.


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Paul
78SC Targa

I suppose it could be the bearings, but I would bet on the tires. In addition to the 911, I put the same brand tires on a second car and it started doing the same thing. It doesn't happen every time I get in the car but it is a pretty frequent trait.

[adamnitti]

I haven't had them balanced since I bought the car. Maybe I should still get them redone when I get my new wheels just to be sure.

I've got Dunlop SP Sports on my car right now, fwiw.

Thanks for the input!

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Adam Nitti
ajnitti@mindspring.com
www.adamnitti.com
'85 911 Carrera Coupe
PCA member, Peachstate region