RichardL

My recently acquired '89 Carerra (Turbo Look) seems to have developed a slight vibration through the steering wheel at about 75-80mph which is hardly noticeable accelerating through those numbers but is irritating while cruising at that speed. The tyres are nearly new and I had the front wheels re-balanced which has helped but not solved the problem completely.
Any thoughts?

Fassi I

I have the exact same problem. I'm going to get the car aligned. Have you tried that?

lostinatl

'84 911 and I have tried both alignment and balance. Also, changed turbo tie rods after finding corrosion during an inspection, still have same problem as both of you and right around same speed.

jet911

I also have the same issue, however my "wobble" happens around 60 - 65 MPH. After passing through 65 the car stabalizes again. I also have had the rebalance done, new tires, etc., and the wobble - shimmy is still is there. This seems to be an issue for several as it was discussed a while ago.

Regards,
jet
'86 911

RANDY P

Factory or aftermarket wheels? Used to happen with the latter since the wheel was not hubcentric. Can you feel the wobble through the seat or the steering wheel? Also verify the amount of weight used. This could tell if you have a defective tire.

rjp

jet911

I'm running the original 16" factory Fuchs. Have had the wheels balanced and rebalanced. I was told there was probably a flat spot on the tires and that by inflating them to the max and running until they warm up, that they will go back to round at least until the tires cool back down - does not seem to help, thus new tires - balance and rebalance. Still have the wobble. It does seem to come through the seat as well. Suggestions are very welcome!

Regards,
jet
'86 911

RANDY P

last time I had a problem with that, was just before new struts. New struts + corner balance + alignment = no more problem. Takes a pretty bad strut to transmit that bad, and it usually gets more pronounced with speed. As long as the wheels aren't bent, then that's all it could possibly be- unless maybe balancing probs with new 1/2 shafts?

Maybe even try rebalancing tires as a set at a different shop with different machines. Rotate tires left to right as long as the tread is symmetrical. Beyond that, you're into some potentially serious investment to rid yourself of this.

rjp

lostinatl

Good point on the struts, I seem to bottom out and hear the right front rub on big bumps, so my struts may be gone.

I will try that next weekend and add the tower strut also.

RANDY P

Now that, excatly was why I had mine redone. Same exact problem, sounded like someone knocking on the door going over washboard surfaces, esp under 20 mph... But, the car seemed to drive well, so I thought.

Now it's beautiful. Tires and balancing are right up there with Ouija Boards in how to get it right IMHO.

Good luck,

rjp

deven07

What about spring arm bushings? My '71 911T wheel shook terrible from 55 - 75...changed the spring arm bearings, it is totally gone...bearings were in absolute terrible shape...maybe they are just starting to go in your 89?

RichardL

Yes, I'm wondering about the bearings myself! The car has only 30K from new but that's a lot of sitting around over 13 years! It's going next week for a good look over - I'll update the thread if I get an answer.

JamesR

My 88 Coupe(Turbo Look)has the same problem at
around the same speed. It is very minor. If I'm
passing through that speed range on throttle, I
don't feel it. I think another member made a
similar observation. My Coupe has after market
wheels. My mechanics tell me everything is OK
in the front. Here is another monkey-wrench; if
the cruise control is engaged, I really don't feel
it.
Any other observations out there??
JamesR

RichardL

Had my alignment re-done and all 4 wheels balanced by a Porsche specialist - not cheap but the wobble's gone! The "quick-fit" solution was a lot less expensive but didn't sort the problem .... you pays your money....!

Mal

Same problem, same speed range 1980 SC. Check out <a href="http://www.hunter.com" target="_blank">www.hunter.com</a> for location of a shop that has the Hunter GSP 9700 equipment. This checks your wheel/tire combo under loaded conditions and if outside of specs, tells mechanic where to reindex the tire on the wheel. Three of four tires had to be reindexed, followed by rebalancing. One tire had a high spot that need to be "shaved". This completely corrected the vibration problem. The website does a great job of explaining the physics of the procedure and why it may be necessary. Good luck.