Every now and then i get to run the shark (88 S4 auto) at close to 100 mph. I have been noticing some vibration at that speed, especially in the steering wheel. Cruising at any speed below that exhibits none of that vibration (upto around 95 mph)

I recently had to replace 1 of my front tires (dunlop sp8000) due to a rupture and it is newer than the other sp8000 on the drivers side. Should I replace that other front tire, and the rears as well so they are of equal wear? Should I get my front tires rebalanced? They are on 16 inch BBS wheels

I might take out on the PA turnpike this weekend, as police are scarce and traffic is usually very light (esp north of the Lehigh Valley) and give the car a good run from 80 to 140 mph just to really observe this problem.

Thanks in advance

Art

88 S4 Auto
46k
granite green

 

Art, I would suggest 3 things. First, I would have the tire shop de-mount both front tires and run just the wheels on the speed balancer. This way you can eyeball them for proper runout. I had a rear that was slightly warped, and could only be seen with the tire off, and spinning it up on the balancer. If they both look good, then have them re-mounted and balanced. Try some high speed runs, and see if this cures the problem. If not, then you might need to spring for an extra front. Also, I would recommend that you check all of your front end components for proper tightness, and make sure you don't have any worn parts that would allow the suspension to flex in abnormal directions. Hope that helps some.

 

Art,

I can't remember the link, but someone had posted the web address for the new Hunter on-car wheel balancer. (The website will help you find the closest one of these techno-wonders.) On-car is the best way to balance, as it balances the whole rotating assembly, not just the wheel/tire combo.
Just like the factory does.

I think the site was in a reply to Nicole's post a month or so ago about wheel vibration.
Try looking back to page 4, or search the archives.
HTH,

Greg

 

I don't know if this is still true ..But I had the same problem a few years ago and I was told that it was the Dunlop tires..They go out of round...Mine only had a few hundred miles on them..They told me the only way to fix it was to shave the tires to make them round again...I got rid of them and have not had the problem since...

Dave
79 Oak green metallic 5 speed

 

Where did you have the tire(s) replaced? A regular tire shop will balance your tire in ounces. Porsches should have theirs balanced to the gram.

The P/O of my car replaced the tires with Dunlop SP 8000's. They came with the "regular" weights used for balancing tires. They were attached to the exterior lip of the stock wheel(s).

I experienced vibration at 70+ MPH. I took it to my Porsche shop and had them re-balance all four wheels. They used adhesive weights on the inside (backside/interior) of each wheel. Results: no more vibration.

 

I need front exterior wheel weights on my 79, but do not which ones to buy? Any Help?

 

I had a similar problem, and only found the cause when I went to a better tire shop. He called me back and said "bring two wheels, because two or yours are going in the dumpster". They looked fine to me but were bent. the before and after was amazing.

 

I had my new tires balanced with the Hunter load balancer. Difference is night and day!

 

Randy has had Dunlop's on his GTS since he bought it 3 years ago. He's had good luck with them and bought another set when he wore out the ones the PO had on the car. FWIW

 

This time around took mine to the local Porsche dealer and the car drove smoother than it ever has since I owned it.If you have a good dealer close by maybe give them a try for a mount and balance.This time I ran (Continental Conti Sport Contact) from Tire Rack.
I had them do the rack,mount and balance all 4 tires with wheel alignment.
It might be more at the dealer but the result was one smooth riding car after at any speed.

 

Had an 01 Boxster S. Drove smooth. Added those metal crested valve stem caps. Started vibrating above 80mph. Put plastic back on and back to smooth. Get your wheel/tires rebalanced. Maybe a weight fell or washed off.