Is aligning tires on a Mercedes Benz require a special expertise?
I’ve owned two MBs and have had problems with shimmy at high speeds on both, usually after new tires or rotation by a non-Mercedes repair shop. It has become my standard practice to use an inexpensive auto/tire store first then fine-tune the tires at the Mercedes dealership.
My current 190E, for example, had tires rotated on Tues for a 1700-mile trip I finished Fri. Max speed of 62 mph for 1700 miles takes a lot longer than at 75 mph! I’m exhausted but the shimmy and shaking was so bad, I though the tires would pop off. And, the steering wheel rattled in my hands. The shimmy was less severe with very smooth roads (newly tarred) and straight-away (car did shimmy on curves) so occassionally I could go up to 70 mph. But, not the 80 mph I know the car can do–not that I would break the speed limit, of course.
Have I been lied to about “finicky” MB alignment? Or have I merely encountered incompetent tire stores in 4 different states for 2 different Benz cars?
Mercedes are pretty sensitive to wheel end vibrations. This means that the tires have to be balanced well, and not be terribly out of round. New Mercedes come with specially screened tires for both balance and run out - but tires available on the open market aren’t screened to such low levels of balance and run out.
Most balance machines will measure balance pretty well, but only a small number of balance machines will also measure run out. These machines are fairly expensive so many tires shops do not have them - while many car dealerships do, because diagnosing a vibrating car requires that the tires and rims be eliminated as a source.
Mercedes sometimes uses fairly aggressive alignment settings to get good handling. Not only is that not good for tire wear, it also causes irregular wear - which comes out as either noise or a vibration (same thing only different frequencies!)
The source of all this is the European preference for good handling and traction. Some of their roads are pretty low friction surfaces. This also means they do not use high mileage (low grip) tires.
In the US, tire wear is an important issue and handling is not. Many Mercedes dealerships know this and adjust the alignment to promote better tire wear I’ll bet most alignment shops do not know this and use the factory settings.
Rotating tires could put an irregularly worn tire in a position where the driver would feel it.
Bottom line: Many tire shops are not equipped to handle finicky cars and a Mercedes is one that is likely to be. However, there are tire shops that are - and certainly a Mercedes dealership is in the best position to know the peculiarities of its products - and they do have peculiarities.
I have had good luck with Michelin tires when I choose to spend the extra money for them. For me they have typically required a very small or no wheel weight when new for good balance. Also, Michelins, for me, have been very good at staying in balance as they wear. Other brands might have approached their quality by now but I don’t know who they are.