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Strange premature wear on both REAR tires and brake rotors. At 30,000 miles the fronts look like new. How/why is the possible? It doesn't seem normal that the rear wears so much faster than the front.
 

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rear TIRES/ROTORS CLS 550

Have strange wear in the REAR only. At 30,000 miles both rear tires and rotors are worn out. Front tires and rotors look new.

How/why is there this discrepancy between front and rear?

Have 2007 CLS 550. Any ideas???
 

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Can you tell us what your wheel and tyre sizes are, front and rear?

If these are mismatched the speed sensors will be commanding the ASR/ESP (traction control) to correct the problem i.e. braking the affected wheels. This will cause tyre, brake pad and rotor wear as well as a higher fuel consumption.

I think from memory the difference between the rolling circumference of the wheels must be within 3%.

Just out of interest is your cruise control working properly?
 

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Thanks for the reply. Note that all tires/brakes are original still. And it is interesting to me that the front tires are different than the rear. Front 245 40 R 18 93V M+S, Rear 275 35 R 18 95V M+S.

Cruise control works fine. Gas mileage is good.

Rear wheels are very dirty from brake pad wear and rotor scoring.
Any idea what is causing all this?
 

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Dutch, sorry for the mundane questions but what distance, miles/Kms has the car covered from new? Are you the first owner?

Have you ever had the brake pads changed? Has the brake pad warning light ever shown up on the dashboard?
 

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Rear tire/brake wear

I bought the SLC 550 with 3000 miles, so I'm sure the brakes and tires have never been replaced. Even though the rear tires are warn beyond the safe limits, and the rear brake system is showing severe wear compared to the front, the brake wear warning has not yet come on. Nothing has yet been replaced or changed
 

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It is almost like the rear brakes are dragging a little bit. You normally go through to sets of front pads before you need a set in the rear.
 

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Good point regarding dragging read brakes. I'll try to test this theory by checking on the temperature of the rear rotors compared to the front.
 

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It is almost like the rear brakes are dragging a little bit. You normally go through to sets of front pads before you need a set in the rear.
I can understand the rear drum brakes dragging but not the disc brakes !

From what I can gather Dutch bought the car with 3K Miles. No tyres or pads have yet been changed.
Dutch does mention that now the rear tyres, pads and rotors are very worn, so I am assuming that the car has now covered around 15 - 20K miles at least.

We still don't know the MY of the car or the distance covered. However if it is a newish low mileage vehicle the MB warranty will cover any defects, especially anything related to safety issues such as brakes.

Dutch, so we can help you more, can you please tell us the manufacture year of the car and the current Speedo reading?
 

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Manufacturing date is November 2006. Total mileage is just under 30,000. Purchased car with 3,000 miles on it. Have had no other problems.
 

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Our local MB dealer in Bellingham, WA says that this is all "NORMAL". However I find this tough to accept.
 

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Dutch, if after 30,000 miles you still have the original tyres and brake pads, I can only say you really have had value for money.

I would recommend that you replace your pads and tyres as soon as possible!
You may want to consider ceramic pads such as Akebono or EBC to reduce brake dust.

Reluctantly I find myself in agreement with a dealer inasmuch as that after 30,000 miles the brake and tyre wear you describe is 'normal'.
 

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Thanks RedLiner. I'm beginning to think you (and the dealer) are correct. HOWEVER, I'm still puzzled that there is such a difference between the front and rear. The front systems still look almost new. Why would the rear be "designed" to fail so much quicker? There may be a reason that isn't very obvious. Thanks for your help though.
 

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Dutch, the rears are wearing faster than the fronts because the car is rear wheel drive.

One of the problems also is that especially with your tyre sizes, you can't rotate them around the car to even out the wear.
I have the same problem inasmuch as I can't rotate my tyres because of the directional tread pattern.

Please let us know what brand of tyres you fit as replacements, here's a few suggestions Michelin Pilot Sport, the Continental Extreme Contact and Pirelli PZeros all will work well with a CLS 55 ;)
 

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Dutch, the rears are wearing faster than the fronts because the car is rear wheel drive.

One of the problems also is that especially with your tyre sizes, you can't rotate them around the car to even out the wear.
I have the same problem inasmuch as I can't rotate my tyres because of the directional tread pattern.

Please let us know what brand of tyres you fit as replacements, here's a few suggestions Michelin Pilot Sport, the Continental Extreme Contact and Pirelli PZeros all will work well with a CLS 55 ;)
Say what? Psssssst.... (when traveling forward, braking causes force (m*a) to shift forwardt, where 90% of the braking occurs.)

Dutch, you are absolutely correct in that the fronts are expected to wear at 2-3 times the rate of rears. I have heard stories similar to yours, but they are few and far between.
 

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Say what? Psssssst.... (when traveling forward, braking causes force (m*a) to shift forwardt, where 90% of the braking occurs.)

Dutch, you are absolutely correct in that the fronts are expected to wear at 2-3 times the rate of rears. I have heard stories similar to yours, but they are few and far between.

GS, I think you are missing my point about tyre wear! Each time a rear wheel drive car accelerates, which tyres are taking the brunt of the action? certainly not the front tyres!
 

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Oh sorry, I thought pad wear and not tire wear was the subject. Yes, rear tires wear faster on RWD vehicles (unless there are lots and lots of turns involved).
 

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Me too, I was talking tyres and you brake pads :)

Just for clarity about rear brake pads and rotors wearing faster than fronts, I fully understand why front brake pads and rotors wear faster than rears and I can understand rear brake shoes dragging in their drums (bad adjustment, footbrake left on a little).
I can't though see how both rear hydraulic disc brakes can drag? The master brake cylinder which is a dual circuit system will operate at the same ambient air pressure??
I can visualise a problem with say one rear brake calliper piston which may be seized or partially seized causing pad and rotor wear, but both wearing at the same rate seems unlikely.

If their is a common problem with this scenario could someone please enlighten me :roll:
 
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