Excessive rear tires worn out
 

Expert advice please ... !

My car is a 1987 W124 300E, right hand drive.

Both of my rear tires have been wearing out excessively fast.

First, I have changed to a new set of 4 Yokohama AVS Sports 205/55/16. Both of the rear tires were completely worn out after 5,000 km ONLY. The front pairs were OK. Pressure of all 4 tires were about 250 psi.

Then I changed the rear pair (only the rear) to Falken tires; at the same time, my mechanic had changed the two lower arm links of both back wheels. Pressure of all 4 tires had been reduced to 210 psi.

By now I have run about 10,000 km but the rear tires seem to be about 85% worn out already. The front pair of Yokohama are still OK, about only 50% worn out.

Notice that always the left back tire worn out more than the right back tire.

HELP ... what could have gone wrong? This is frustrating.

Ed

First, what do you mean "Pressure of all 4 tires were about 250 psi"?

Are you following the Mercedes recommended tire pressures? Please clarify, I am confused.

Sorry ... I get the unit mixed up. I mean the tire pressure was previously set at 2.5 bar, which was then later changed to 2.1 bar.

Mercedes recommended tire pressure is 2.1 bar.

My point is, I noticed the higher-than-recommended tire pressure might be the culprit of the excessive worn out of the first pair of Yokohama tires. Then I changed the tire pressure to be within the recommended tire pressure, which seems to help a bit only. This latest pair of Falken tires are about 85% worn out only after about 10,000 km!! So far I have onwed at least 10 cars before and almost any brands of tires I have used before can last at least 20,000 km. And, for this car, the excessive worn out only happens at the rear and the left back is more serious than the right back ... so I just recken something is not right.

Is your car lowered because w124's usually have a problem with the rear camber if the suspension is lowered. This causes excessive tire wear just like you are currently experiencing.

Thanks. The car is lowered.

May I understand why lowering the springs causes the chamber problem which in turn affects the rear tires worn out (but not the front tires)?

Lowering a car causes the suspension to have a negative camber. The w124 cars can easily be adjusted for camber correction in the front suspension which is what I believe has been done to your car when it was initially lowered. Adjusting the rear camber on these cars is very difficult as it only allows for very small correction which would not be enough if you lowered your car pretty much. This is why your front tires don't wear out as much as your rear tires. Assuming that all your rear suspension components are in good condition then one way of correcting your rear camber problem is by getting an adjustable rear camber link which allows for a greater correction of rear camber specifically for lowered cars.

This is an excellent example of the consequences of radically changing the designed ride height.

Thank you all very much for the advice.

Besides the springs (and hence the camber), are there other possible causes? What about wheel alignments such as toes?

Edwin

Another specific question: How are your tires wearing? Just the rears on the insides? That would definately indicate too much camber.

haasman

I just took another detailed look at the tires. I would say both of the rear tires seem to wear out quite evenly, when comparing the insides and the outsides of each tire respectively. However, I notice that the left rear tire is wearing out faster (and again, evenly) than the right rear one.

Note that my car is right hand drive, in case this matters.

Any help would be appreciated.

Hello experts ... are there other advices on the problem?

Thanks in advance.

Toe will wear one side or the other, but usually not both evenly. You also have Yoko AVS Sports, which probably shouldn't last that long anyway... 10,000 miles is probably not unreasonable... If there is no feathering, and tread depth is uniform from side to side and in the middle then you probably just need different tires if you want them to last longer.

-brian

Thanks now I understand the matter better. Just some additional feedback:

(1) My Yoko AVS tires only lasted 5,000 km (not even in miles). The irony is I had 4 Yoko AVS tires but only the rear pair had been worn out at this mileage. Since then, I have changed the rear tires to Falken Azena, which is now about 85% worn out after around 10,000 km (not miles). The interesting part is, till now my front pair is still the Yoko AVS, which has therefore lasted 15,000 km and is only 50% worn out! Does this mean tire problem or the car's mechanical problem?

(2) What I can see on my rear tires:
- worn out seems to be even, inside vs outside.
- no feathers, or other abnormal/unusaul patterns
- left rear tire worn out relatively faster than the right rear, but both appear the same as above.

For camber problem associated with a lowered suspension, a tire should be worn out more at the inside than the outside because of the uneven pressure exerted towards the tires at the two edges. Toes should display a similar situation. Am I correct?

Then what is/are the mechanical problem(s) I am having and why the left rear is wearing out (evenly) faster than the right rear?

Your rear tires will definitely wear out more than the front because your car is rear wheel drive and depending on the driving conditions (sudden accelarations, lots of uphill climbing, etc.) your drive wheels will not last as long as your front wheels, that is why there is a need to constantly rotate your tires so they would all last equally as long. However, 5000km is sure on the short end of tire milage. As I previously posted, lowering a car improperly causes the suspention geometry to change (not just camber) dramaticaly leading to excessive tire wear. I experienced the same problem with my 260E since I lowered it by 2 inches by simply cutting off the springs. The rear tires were worn out more excessively though the wear patern on the tires was more or less even. My mechanic suggested that I change to real lowering springs so I used H&R but I still cut this as the car was still too high for me. The tire wear was less than when I was using chopped stock springs but was still wearing out abnormally. What I did next was use a higher rubber bump on the rear springs as I had the thinnest (1 bump). The rear end was higher than the front as a result of this but this is hardly noticable. However my front and rear tires now wear out at almost the same rate. You might want to try this out first ( getting a higher bump for ypur springs). This will give you the added benefit of being able to check the other rear suspension components as well.

Hope this helps.