Front End Shimmy

[Johnb911]

Just got he car on the road this weekend.

have a shimmy in the wheel at 55-60 ish (Thats where its worst).
Replaces the bearings this winter and races.
Readjusted the tightness after a 45 minute drive.

Seemed to help a little.

The car sat almost in the same place all winter.
Never below freezing in the garage.

What are to odds that I have some flat spots compared to something else.
Do they go away?

What else should I check?

[lfot]

Get your wheels and tires balance checked. If you have flat spots, that could also throw off the balance along with vibrations from the flat spots. Ask me how I know.

[911s55]

Get tires balanced, see if they are out of round and how old are they and manufacturer? 55 and 60 mph is typical speed for out of balance vibration. Do they smooth out above 60?
David

[Johnb911]

It seems to smooth out after 60.

How do you tell if they are out of round?

[lfot]

the tire shop will be able to tell.

[911s55]

You can see it when they are rotating on the wheel balancer.

[Johnb911]

Do they go back to normal or need to be replaced.
The are Estta Supra's.
The Po put them on about 5 years ago.

Maybe 20,000 miles on them.

[911s55]

If it's a balance issue you can fix it, out of round will continue to haunt you inconsistantly. I had my Pirellis' balanced twice last year found them out of round and pitched em, plenty of tread left on them to. Just put new Vredesteins on yesterday, smoooth and sticky!

[Doug Steinel]

I am on my second 911 and I found that I could not get more than 20k miles out of the front tires on either car. There was plenty of tread left, but even after balancing there was a shimmy. Move a pair of these 20k tires to rear and put new, balanced tires on the front. That is what I have to do to get rid of the shimmy.

[JeffreyNMemphis]

I had a seized front brake caliper that caused the steering to shudder at around 55 mph.

[masraum]

It sounds like you probably need new tires. Not necessarily because of the vibration, but because of the fact that the tires are old and probably not very grippy. A nice set of new tires will probably cure things, and don't do what Doug S says above since you should have wider tires on the rear than the front. Moving the current fronts to the back would be a bad idea.

[Paulporsche]

Sounds like your tires could easily be 6 years old, which many people today feel is the limit to keep tires on a car, regardless of tread wear. Some out of roundness does occur during long term storage, but that should go away after a few miles. I'm thinking your carcass and/or belts have worn out, causing the viration. Time for new ones.