Pavegeno928

I had a shimmy between 60 and 70 a month or so ago. Brought the car in and got one of the wheels trued out and it was like butter for the last 2000 miles (I drove from Florida to New Mexico a few weeks ago). Now I am getting the shimmy back between 60 and 70 again. What is wierd is that after 20 minutes or so of driving it goes away but then returns a few minutes later.

Going to bring it in to a local shop to have them pull the wheels again to check balance.

Any thoughts?

Thanks...Geno

Ed Hughes

Tires, alignment, wheels true, balancing, lots of variables. If one of the wheels needed straightening, then whatever caused that damage could have knocked alignment out of whack, which could wear tires in a weird way.

fpb111

Pavagano928,
Long shot - a few years ago we had a tire that did the same thing. Wild out of balance then ok for some distance/time at 60/70. Took it to be spin balanced and it did the same thing on the balancer. It would start to come into balance and then oscillate wildly and then try to tear the balancer off the floor. We decided to change the tire. When we broke the bead a couple of cups of water ran out, bad compressor maintenance?? The tire would balance after it was dried out. I said it was a long shot.

rusnak

I've heard of a wheel shimmy caused by a bad strut. I think it could be a bad strut bearing, or worn shocks.

Pavegeno928

Drove tonight and it was smooth..very odd...one other thing...when there is no wheel shimmy, I still get a vibe that goes through the car from right to left about every 3 seconds...shakes the shifter slightly and you can feel it in the steering wheel and dashboard...as a helo pilot I am very sensitive to vibes so I want to figure out what is causing this. Had an alignment and new rotors and pads about 10 months ago...new turbo tie rods at the same time...local Porsche mechanic highly recommends a local alignment shop here in Albuquerque so I am going to stop by on Monday...thanks for all of the guesses...I'll pass these on to them to look at.

cal44

I look forward to your findings.

pjc

Had this problem a few years back - car was very sensitive to tyre pressures, had to be perfect - too high or too low and vibration kicked in. Changed the tyres to different make and problem solved.

PJC

Pavegeno928

Just got back from the alignment shop...all four wheels were pretty well worn on the inside spreading out...outsides were not too bad but close to the wear bars which I have been watching. Alignment shop said there was no resaon to go any further because I needed to replace the tires as the first step in diagnosing. I'm running Goodyear Eagles and have 20k miles on them. Will update once I get new tires on...think it's time to replace the 17" 964 wheels with 16" Fuchs to get it back to stock...putting a post up regarding aftermarket Fuchs replicas...would be interested to hear opinions...

rusnak

While the tires are off, this would be a golden chance to check wheel run-out if you suspect a damaged wheel. Yesterday I noticed that my 911 tires vibrate until they are warm. It was unusually cold, and the Fuzions seem to get worse flat spots than the Bridgestones.

Ed Hughes

I think a lot of performance tires on a feedback car such as a 911 deliver some vibration from flatspotting until they get warm. My 928 was bad too, but she weighed 1000lbs more than Ruby.

On the subject of wheels......I'd not be keen on any cast Fuchs repros. I also wonder if whatever spacer you run to make 964 wheels work didn't partially contribute to the problem?

Pavegeno928

Found some original Fuchs from Wheel Enhancements...ordering them...will take a few weeks to get them. Will have to baby my tires for a few more weeks...

DesignerGenes

Let me suggest some tires for those new wheels. These are street tires that also work well on the track -- especially on a wet track. Of course, they're not intended for snow and very cold weather, so don't think I'm calling them M+S. The tires need to be broken in -- hard -- before they work best, and DO put plenty of air in them to keep the sidewalls stiff.

Try Kumho Ecsta SPTs. With a wear index of 320, they'll beat much more expensive tires for longevity on the road. I tried them as race tires (on my track wheels), and haven't removed them now in 6,500 miles. I'm guessing I'll see 10,000 to 12,000 on the rear of my 911 Turbo S. That's easily double what Michelins or Pirellis would give me. Just smile when the high-end tire salesman frowns at "cheap tires on such an expensive car." You know better.

talane

Pavegeno, I too understand the Helo vibration...Thanks for you service and I hope you figure out the vibration issue. Bugs the hell out of you doesnt it.

Pavegeno928

Good news...new tires did the trick...completely smooth at all speeds...got 20k out of my Goodyear F1GSD3s...great tires...replacing the wheels and tires next month with 16" Fuchs...will check alignment to prevent excessive inside tire wear...thanks to all for their inputs...learn something new all the time around here...original steering wheel just got recovered...will install when I get back to Florida...