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So I originally took my car to the dealer because my car was hitting my brake when Distronic was activated. Dangerous when driving on the freeway and brake is slammed. As soon as it reached the desired speed I set it at, it would hit the brake then accelerate again trying to reach my desired speed again. Having a V8 in the car, this interval happens every second constantly rocking back and forth. After over 2 months at the dealership, we find out this issue was due to the incorrect tire size. Tires installed 285/30R20 when it should be 285/35R20. This is where my dilemma comes in. I contacted MBUSA corporate after a month an a half to see if I can get some sort of compensation for having the car for not having my car for so long because while doing the tests, they found things wrong with the car anyways which needed to be fixed.
11/29/21 - Car Taken into the shop due to car slamming brake and accelerating when Distronic is activated
12/1/21 - Series of testing not passing. Service tech reached out to Mercedes Benz Germany for an answer.
12/9/21 - Service tech reached out to Mercedes Germany and stated shadow memory and teaching procedure not running. Advised to replace part. Part ordered
Month of December - Huge gap due missing part after part not being delivered. Car can't be put back together.
1/11/22 - Part received installing
1/14/22 - Install complete. Car is not drivable. New clutch not engaging at all. There is no forward or reverse. (I've sent screenshots of this to you in the past)
1/18/22 - Mercedes Benz Germany states transmission needs to be replaced due to an internal failure.
Started to replace transmission.
1/28/22 - Transmission put back together, reprogramming.
1/31/22 - Car put back together, everything's running and car system checks are actually all passing now when it wasn't passing when the car was FIRST brought in.
1/31/22 to today - Found out distronic not working properly due to wrong tire size. Waiting for an answer from corporate on whether I'll be compensated or not. The car is STILL at the shop.
FWIW, my tire size is far from OEM and my distronic works fine on my S580. Aftermarket wheels and tires on one of my previous cars and never had a problem with radar cruise control.
When factory technicians throw out ideas that seem stupid and I agree with last post I think there is no way that this will be the problem. Terrible time to lemon a car, you don't mention what year your car is, but question HOW did you get the wrong size tires from recommended OEM? DId you put them on as replacement or did they come on the car?
Just view it from their standpoint... MB probably spent over $15k trying to remedy your issue. Turns out the problems was caused by something they didn't do (maybe the dealer did it, or a past owner, but not MB NA). They are wayyyyy into the hole for something they aren't really liable for. I believe the tires could cause this issue but it would definitely be very, very low on the list of things someone would check on an otherwise stock late-model MB.
If the car is awd and the rear tires were wrong like this and the car had the stock front tires thats not good for the awd drive train either. I can see it effecting other things too unless the tires were all 4 equally sized, thats a pretty big difference.
If the front tires where the correct factory size of 255/40/20 and the rear were 285/30/20 that is a difference of 4.9% in circumference. I think MB suggests no more than 3% in size difference between the front and rear tires on 4Matic equipped cars and 3% is also best practice for any car. If you have driven it like this for a while and racked up several thousand miles than I suppose it could do damage to the transmission which houses the transfer case. With a 5% difference in circumference the front tires would be spinning slower than the rears and I could see how this would cause some confusion with the speed sensors at the wheels. This difference would also cause a constant slip in the differential and may wear out parts faster. This may be what they are referring too but not sure. Who put the tires on or did you buy the car like this. Carfax should tell you when and who replaced tires. That is where I would start. These cars with all of the fancy safety systems can be very touchy when it comes to any kind of change that might alter a tolerance and confuse the computers. Beautiful car, hopefully you get it all sorted and can enjoy it.
If the front tires where the correct factory size of 255/40/20 and the rear were 285/30/20 that is a difference of 4.9% in circumference. I think MB suggests no more than 3% in size difference between the front and rear tires on 4Matic equipped cars and 3% is also best practice for any car. If you have driven it like this for a while and racked up several thousand miles than I suppose it could do damage to the transmission which houses the transfer case. With a 5% difference in circumference the front tires would be spinning slower than the rears and I could see how this would cause some confusion with the speed sensors at the wheels. This difference would also cause a constant slip in the differential and may wear out parts faster. This may be what they are referring too but not sure. Who put the tires on or did you buy the car like this. Carfax should tell you when and who replaced tires. That is where I would start. These cars with all of the fancy safety systems can be very touchy when it comes to any kind of change that might alter a tolerance and confuse the computers. Beautiful car, hopefully you get it all sorted and can enjoy it.
Thank you. I hope I can get it sorted too so I can enjoy it. Had the car for 3 days before it was sent into the shop :/
Did you buy the car CPO? The fact that a dealership replaced the tires as far as I am concerned takes you out the blame if this is indeed the issue. If you did CPO I think you have some lemon law options assuming your in CA it isn't that hard to lemon it, but that said the car is beautiful and replacing it now is a PITA.
So I originally took my car to the dealer because my car was hitting my brake when Distronic was activated. Dangerous when driving on the freeway and brake is slammed. As soon as it reached the desired speed I set it at, it would hit the brake then accelerate again trying to reach my desired speed again. Having a V8 in the car, this interval happens every second constantly rocking back and forth. After over 2 months at the dealership, we find out this issue was due to the incorrect tire size. Tires installed 285/30R20 when it should be 285/35R20. This is where my dilemma comes in. I contacted MBUSA corporate after a month an a half to see if I can get some sort of compensation for having the car for not having my car for so long because while doing the tests, they found things wrong with the car anyways which needed to be fixed.
11/29/21 - Car Taken into the shop due to car slamming brake and accelerating when Distronic is activated
12/1/21 - Series of testing not passing. Service tech reached out to Mercedes Benz Germany for an answer.
12/9/21 - Service tech reached out to Mercedes Germany and stated shadow memory and teaching procedure not running. Advised to replace part. Part ordered
Month of December - Huge gap due missing part after part not being delivered. Car can't be put back together.
1/11/22 - Part received installing
1/14/22 - Install complete. Car is not drivable. New clutch not engaging at all. There is no forward or reverse. (I've sent screenshots of this to you in the past)
1/18/22 - Mercedes Benz Germany states transmission needs to be replaced due to an internal failure.
Started to replace transmission.
1/28/22 - Transmission put back together, reprogramming.
1/31/22 - Car put back together, everything's running and car system checks are actually all passing now when it wasn't passing when the car was FIRST brought in.
1/31/22 to today - Found out distronic not working properly due to wrong tire size. Waiting for an answer from corporate on whether I'll be compensated or not. The car is STILL at the shop.
4 Wheels are all OEM 20s? Your front and rears tires all same size correct? While I did not calculate the difference between 30r and 35r, I don’t see that dimension being the initiator of the problem. I would expect the system to compensate for a uniform differential.
One more observation, while I don't run in snow country, consider the guys who swap to a winter tire set up. Their R differential might be greater than yours. Just a guess.
Let me know if I’m wrong as to your tire sizes. If you are the same on all 4 corners, I think you are getting a line of bs from MB.
4 Wheels are all OEM 20s? Your front and rears tires all same size correct? While I did not calculate the difference between 30r and 35r, I don’t see that dimension being the initiator of the problem. I would expect the system to compensate for a uniform differential.
One more observation, while I don't run in snow country, consider the guys who swap to a winter tire set up. Their R differential might be greater than yours. Just a guess.
Let me know if I’m wrong as to your tire sizes. If you are the same on all 4 corners, I think you are getting a line of bs from MB.
Good looking car btw.
All S63 cars come with staggered wheels and tires. That is not the point, the point is the difference in rolling diameter. That is why there is a specific combo of tire sizes for this set up, to ensure that the rolling diameter does not exceed 3%. The OP has what appears to be a set up with almost 5% of difference in rolling diameter from front to back. Not saying this is causing any issues but it is out of spec for the car and should be corrected. I would guess a selling dealer just threw on what they had in stock as it was close in size and sold the car.
All S63 cars come with staggered wheels and tires. That is not the point, the point is the difference in rolling diameter. That is why there is a specific combo of tire sizes for this set up, to ensure that the rolling diameter does not exceed 3%. The OP has what appears to be a set up with almost 5% of difference in rolling diameter from front to back. Not saying this is causing any issues but it is out of spec for the car and should be corrected. I would guess a selling dealer just threw on what they had in stock as it was close in size and sold the car.
Got it. I missed the OEM stagger for a 63. I agree with Superpop.
02-17-2022, 12:33 PM
