I have a 2002 S55 and the car vibrates (when cold ??) at speed between 30-45.
All the tires are almost new – 100-200 miles on each and they have been recently
balanced by the dealer. Even the front and back alignment has been done and everything is within the factory specs.

Dealer indicates that the problem is due to performance tires - when the car sits for few days without being used, it creates a dimple in the tire which causes the vibration. They say it should go away after it warms up, which does not happen. I have never had this problem before for almost a year when I was using the car on a daily basis, but now it happens even when the tires are warmed up. The problem is intermittent and as you know, the problem never happens when the car goes to the dealer for diagnosis.

Does anybody have this kind of problem?
Would appreciate any input which might be helpful.
Thx
Ashvin

 

It's not clear. Did you drive the car with other tires that rolled okay?

Assuming the tires are balanced, I think you may have an out-of-round situation. Either the tires or the wheels or both. The high and low spot differences become less severe as the tires heat up and the air inside expands.

You can get the wheels and tires "indexed" at a good tire store (like Goodyear, Firestone, etc). They match the high and low spots on each wheel/tire set. It took care of a persistent and phantom shaking on my SL.

What the dealer said about a "dimple" doesn't apply to modern tires. However, it's easy to wear a flat spot on high-performance tires. A burnout, hard corner drift, or hard stop can wear a spot on the tire(s) that will cause vibration. In other words, the "dimple" is permanent, not something that will work itself out as you drive the car.

 

Are you sure that the tire pressure is correct. I mean cold tires to the exact specs. Otherwise it could be quite a few things.

 

Hey Lugnut,

He has the same problem that I have. Remember, I'm the one who has nursed my S420 back to health after a long life of abuse.

At anyrate, I put 17" wheels on the car and 225/55/17 tires. I've been from tire shop to tire shop. Finally, I went to the Goodyear Tire Shop and checked out the rims - perfect - force balanced the tires - perfect - still get that vibration just like he does. Now, I've considered replacing upper and lower ball-joints and tie-rod ends, even the shocks and springs, but somehow I don't believe they are the problem. The only other thing that I can think of may be the drive shaft is out of balance, or the engine or transmission motor mounts need to be replaced. What do you think? I know it's rare, but hey - it could happen...couldn't it?

 

Yeah, I just think it's better to start on the simple stuff unless it's obvious what's causing the problem.