New tire balance question

[loneryder]

Shaking in the seat or floor that begins around 68 mph, especially if the shaking seems to move around the car, is a CLASSIC sign of out of round tires or tire that need to be road force balanced.
A few other thing can cause that issue too, such as a damaged tire or a loose belt, but in general, tire related.
MB 4matic drive trains also have a rubber flex disc near the rear axle, so you'll need to inspect that too. They can go bad after years of use.
How many miles on your MB?

If I were to guess, just a guess, you got a great deal on those tires because they were seconds or somehow not up to standards.
I put Pirelli MOE tire on my 4matic, and the tire shop road force balances everything they sell, the result, smooth as glass at any speed.

70k on it. It wasn't a special deal just $100 rebate from Pirelli. Thanks for the info. I'll get them checked for out of round.

 

[CapriRacer]

Go to Hunter Engineering 's web site. Look for balance machines in your area. All of Hunter 's balance machines are RoadForce machines and can deal with out of round.

 

[SumGuy]

What I've found in my area (SW-Ontario) is very few independent or chain garages have road-force balancers, but many or all car dealerships have them.

 

[JohnnyG]

70k on it. It wasn't a special deal just $100 rebate from Pirelli. Thanks for the info. I'll get them checked for out of round.

Yes, I got that deal too, but still put out $1500.00 for 4 tires! RFB included though, so I was ok with it.