W126 / 300 SDL Question

Question.

'86 MB 300SDL that has a 'vibration' when driving down the road.

It felt like a tire badly out of balance. I had Goodyear Allegra tires on the car. The vibration would come and go at different speeds.

Well, I've just dropped $1200 on new wheels & tires, and for the most part, the vibration is gone. But not completely. I was going to change them out anyway, so no big deal. (They look great!)

This is the 3rd set of wheels / tires on the car since I've owned it. Bought it used off of eBay. So, no history. The two previous sets of tires had uneven tire wear on the front tires, side to side. Like it was 'scalloped' in the middle of the tread.

I've had all the suspension components checked and replaced if nec. The front end aligned, etc. My mechanic says that there is nothing mechanically wrong that he can find on the car. Had new OEM Bilstein shocks installed too.

I've read about checking for collision damage by checking measurments on the frame / body.

Anyway, I'm rambling here. Any ideas or similar experiences out there? I don't want to live with annoying vibrations with all the $$$ I've invested in restoring this car.

Scalloped tires indicate an out of balance condition. The "scallop" is caused when the tire, having been briefly lifted off the pavement, hits the pavement again - somewhat like an airliner's tires when the plane touches down.

Tread wear on the inside and outside of the tread can be caused by under inflation, cowboy driving, incorrect camber angle (perpendicular to pavement) and incorrect toe-in which scuffs the tread on the pavement. All these are well known to an alignment shop.

As to the current vibration I'd have the tires dynamically balanced off the car. This is sometimes necessary to overcome a tire's imbalance. High speeds cause tires to act like gyroscopes so high speed balancing is needed to correct both static (heavy spot) and dynamic imbalance (inside wall heavier than the outside wall, for instance).

You've done everything else.