W210 1998 E300 Right Rear Tire Prematurely Wore Out

[nhdoc]

Yesterday I was looking over the E300 and saw my right rear tire was worn in the middle of the tread...classic sign of overinflation, though even the inner and outer bands had more wear than the left side tire. Basically the tire is worn out with the center of the tire down to the wear indicators.

The funny thing is that I usually run all 4 wheels at 30-32 PSI and this one was at 31. But, it was about 2 PSI higher than the others...is it possible that 2 PSI could result in such dramatic tire wear issues?

The left rear looked OK. These are my snows (Pirelli 210 Snowsports) and probably only have around 10K miles on them so this is really premature wear. They have always been on the same corners over 2 seasons (the right rear was in the same location last season). I don't think there is anything in the alignment that could cause this but am wondering if the differential could be sending uneven power to the rear wheels causing the right tire to wear out so much faster than the left or am I just overthinking this?

No, this is NOT over inflation, it is UNDER inflation. Bias ply tires will wear down the middle if they are over inflated even by a few pounds. For over inflation to cause wear down the middle in a radial tire, it must be EXTREMELY over inflated.

Just a few pounds of under inflation will cause what you are seeing, particularly with the tire on the rear, AND particularly on the right rear. I understand why the rear aggrevates this, but I have never understood why the RIGHT rear is worse about this than the left rear.

In about one million miles of driving MB's I have found that running 35PSI in the rear and 32PSI in the front on any mid size MB, including the 123, 124, 210 or 203 cars will work well. If you run the rears at 32PSI you are going to experience what you have seen.

Good luck,

[nhdoc]

Thanks Larry,

So, you have seen the "right rear wear" phenomenon before then?

I'll try the 35/32 PSI rear/front pressures as you have recommended. Should I bother having the alignment checked or is that then a waste of time and money at this point?

Yes, I have seen the "phenomenon" numerous times. I would not bother with checking the alignment. Remember to adjust tire pressure only while tires are cold. I prefer to do it in the morning, but I have read that if the tires have not rolled for an hour you can adjust pressure.

Rotating your tires will help alot. It can't do anything about a tire that is already gone, but it will make the SET last longer.

I went through a period of liking unidirectional tires, but that honeymoon is over. I now use tires that can be used rolling in either direction, which applies to most tires that you might buy for your Benz, and I then use a cross rotating pattern.

When rotating I cross the front two tires to the back and then move the rear tires forward keeping them on the same side of the car. In recent years I have seen lots of tires that begin roaring, mostly on front wheel drive cars, but also on rear wheel drive. Rotating the tires in this manner will go a long way toward preventing this and let the set wear out evenly.

Good luck,

[nhdoc]

I recall in the early days of radials they recommended against cross-rotating any radial tires, but I understand that has changed. I've always only done front to back out of habit but will start crossing them now that I have seen what can happen to the right rear.

Thanks again for sharing your expertise, advice and experience.

[e300D97]

I might not be correct, but isnt the right rear tire your primary tire for propelling the car Doesnt the differential sent power to the right side primarily? And if in reverse it sends it to the left. I think I am remembering correctly from my days in auto mech. shop class. This coupled with the slight over inflation, and maybe alot of short trips

Originally Posted by e300D97

I might not be correct, but isnt the right rear tire your primary tire for propelling the car Doesnt the differential sent power to the right side primarily? And if in reverse it sends it to the left. I think I am remembering correctly from my days in auto mech. shop class. This coupled with the slight over inflation, and maybe alot of short trips

Yes, this is correct to a point. It is not by design, but in an open differential it does seem that the right side receives more torque than the left for some reason. Most all our MB's have an open differential.

I remember when I was a dumb teenager, the kids that did burnouts of sorts would usually lay rubber only with the right side. I couldn't afford to play that game.

Yes, in the early days of radials, it was suggested that the tire rotate in the same direction for its entire life span. That suggestion began to be rescinded in the nineties. Now days, you even see cross rotation diagrams in owners manuals.

Have a great day,