racer12

I have 18,000 miles on 20 inch tires .They have developed a wump wump wump sound at 60 miles per hour in the rear .Anyone else encounter this at 18,000 miles. Dealer says it is normal

Koenig1

Personally, I would take the car over to a reliable tire dealer and ask them to check the tires for steel belts that may have shifted within the tire. Years ago, I spent an awful lot of time trying to convince a Chrysler dealer about a balance problem. After no success, I drove over to a decent GoodYear dealer, and 5 sec later he was able to point out 3 of my 4 Eagle GT tires with belts that had shifted! If you want to try looking for it yourself... you need to spin the wheel, looking at the center treadline, and see if there is any 'side to side' 'wobble' as it spins. Unfortunately, a 4matic doesn't like to spin freely!
good luck.... you'll think the tires feel unbalanced, yet a dealer will try balancing, but rarely will they notice a slipped belt. This Chrysler dealer even had a machine to spin the tire on the car, looking for a screwed up hub, or brake disc.... after seeing what the GoodYear guy was looking for.... it was sure obvious.... good luck!

racer12

I have an appointment at a Chev dealer today to have them checked on a Road Force balancer.It hould tell which one is junk.The Benz dealer said that these tires can be a pain in the butt.I need to go up to 255 45 20 size to get Michilins when I do all four. Thanks for the reply

racer12

The rear tires are junk

OldMerc94

My run flats failed at 19k mi - belts were exposed.

If they are non-run flat OE tires, I would check to see if the wear bars are exposed. Pretty easy to tell - just look between the treads for a thin bar connecting across the tire.

These MLs can eat through the OE tires pretty quickly; particularly if they aren't rotated.

Usually Pirelli will give a small amount back if the tread is worn down before the mileage warranty.