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Rear tire thread separation at high speed. Car had 26.000 miles
Few months back, during high speed highway driving right side rear tire thread separated from side wall. Heard a "thump" sound and a small vibration. Stopped the car, inspected the best way I could. Couldn't find any issues, tire pressure normal. Drove the car conservatively and problem seemed to have disappeared. 2 weeks ago, on another high speed run, same episode. This round, tire lost a few psi but never went flat. Upon inspection, while restoring the correct pressure, I noticed the separation. Drove the car to the dealer hoping the tire would have been covered by manifacture warranty. I was told that Pirelli P-zero, being summer tires and being staggered (AMG package) are only warrant 25k miles and car was over that milage (27k). 2 rear tires, and an alignment, over 1k dollars. Not too happy about this Mercedes Benz.
In what regard is this the car's fault? Tread separation generally happens if the tire overheats and that generally happens if the wrong tire pressures were used, causing the deflection of the tire to heat it up to the point where it overheats. Which pressures from the sticker inside of the fuel door were you using and did you use the correct one whenever you loaded up the car? The max load pressure is for when you have rear passengers and cargo in the trunk. The rear tires and the front tires for that matter need to be inflated to a higher pressure if the car is being loaded up. The other pressure on the sticker is the normal load pressure to be used when you just drive by yourself with an empty trunk. Don't go by the sticker on the driver's door. Blame the USDOT for legislating a useless sticker on the door.
This reminds me of an experience a few years ago. Was heading up on I-5 from Los Angeles and just as I was passing this BMW 3-series, the tread completely separated on their rear left tire and rolled my way. Literally, part of his rear tire was about to pass him. I had to gun it so the separated tread didn't hit me. I saw in the rearview mirror that they safely managed to pull over on the side of the highway. This could have gone south easily. Unfortunately, most American drivers have no clue about tire pressure. Remember the Firestone incidents in the 90s where a bunch of Ford SUVs flipped over and some people got killed? Turned out they all used the wrong tire pressures and the tread separated on one or more tires due to overheating. This is partly why the door sticker in the USA now only lists the max load tire pressure as it's supposedly the safest pressure, but it's the wrong pressure unless the car is loaded up accordingly.
If you are convinced it was a tire manufacturing defect and you can demonstrate that you were using the correct recommended tire pressures, file a case against Pirelli. Tread separation is a huge safety issue obviously. This goes beyond tire warranty.
PFL205.064 with M276.823 (Oil pump solenoid defeated)
Originally Posted by superswiss
In what regard is this the car's fault? Tread separation generally happens if the tire overheats and that generally happens if the wrong tire pressures were used, causing the deflection of the tire to heat it up to the point where it overheats. Which pressures from the sticker inside of the fuel door were you using and did you use the correct one whenever you loaded up the car? The max load pressure is for when you have rear passengers and cargo in the trunk. The rear tires and the front tires for that matter need to be inflated to a higher pressure if the car is being loaded up. The other pressure on the sticker is the normal load pressure to be used when you just drive by yourself with an empty trunk. Don't go by the sticker on the driver's door. Blame the USDOT for legislating a useless sticker on the door.
This reminds me of an experience a few years ago. Was heading up on I-5 from Los Angeles and just as I was passing this BMW 3-series, the tread completely separated on their rear left tire and rolled my way. Literally, part of his rear tire was about to pass him. I had to gun it so the separated tread didn't hit me. I saw in the rearview mirror that they safely managed to pull over on the side of the highway. This could have gone south easily. Unfortunately, most American drivers have no clue about tire pressure. Remember the Firestone incidents in the 90s where a bunch of Ford SUVs flipped over and some people got killed? Turned out they all used the wrong tire pressures and the tread separated on one or more tires due to overheating. This is partly why the door sticker in the USA now only lists the max load tire pressure as it's supposedly the safest pressure, but it's the wrong pressure unless the car is loaded up accordingly.
If you are convinced it was a tire manufacturing defect and you can demonstrate that you were using the correct recommended tire pressures, file a case against Pirelli. Tread separation is a huge safety issue obviously. This goes beyond tire warranty.
Sorry to hear about this scary incident, glad to hear you came out unscathed.
Ya, it also doesn't help that dealerships often over inflate tires, with the heat wave coming across North America, the tires are dangerously too close to the maximum tire pressure a tire can handle, and depending on driving behaviour, I guess BMW drivers... they also hit the final trigger point to cause structural failure of the tire.
Thank you for all the replay and suggestions, just to add that the car was driven at very conservative speeds for most of the lifetime of the tire. To answer to the pressure post, I fly for living and I inspect my car conditions throughly before driving. All my inspections and checks are up to date and upon taking the rear tires off the car for replacement after the event, their conditions were plentifully within limits specs. My tires have been inflated at the correct pressure in all my vehicles wich spans from AMGs and Porsches and everything else in between. My observation was about Mercedes Benz dealer not giving a second thought to replace an obvious defective tire under warranty. But rules are rules and the tires had 27k instead of 25k.
This car is far from a performance car, with the driving package and a formidable 2 liter racks up 35 mpg as my daily drive and I'm very happy with it. Cheers
PFL205.064 with M276.823 (Oil pump solenoid defeated)
Originally Posted by Heloflyer68
Thank you for all the replay and suggestions, just to add that the car was driven at very conservative speeds for most of the lifetime of the tire. To answer to the pressure post, I fly for living and I inspect my car conditions throughly before driving. All my inspections and checks are up to date and upon taking the rear tires off the car for replacement after the event, their conditions were plentifully within limits specs. My tires have been inflated at the correct pressure in all my vehicles wich spans from AMGs and Porsches and everything else in between. My observation was about Mercedes Benz dealer not giving a second thought to replace an obvious defective tire under warranty. But rules are rules and the tires had 27k instead of 25k.
This car is far from a performance car, with the driving package and a formidable 2 liter racks up 35 mpg as my daily drive and I'm very happy with it. Cheers
I see, sounds like you did your part, I wonder if there were any hidden nail punctures that cascaded, also what was the tread depth?
Thank you for all the replay and suggestions, just to add that the car was driven at very conservative speeds for most of the lifetime of the tire. To answer to the pressure post, I fly for living and I inspect my car conditions throughly before driving. All my inspections and checks are up to date and upon taking the rear tires off the car for replacement after the event, their conditions were plentifully within limits specs. My tires have been inflated at the correct pressure in all my vehicles wich spans from AMGs and Porsches and everything else in between. My observation was about Mercedes Benz dealer not giving a second thought to replace an obvious defective tire under warranty. But rules are rules and the tires had 27k instead of 25k.
This car is far from a performance car, with the driving package and a formidable 2 liter racks up 35 mpg as my daily drive and I'm very happy with it. Cheers
Fair enough. It's just that the tread on a tire doesn't just separate. You probably know that as well as I do. The dealership just follows protocol, so hopefully you kept the tire. If so you need to go after Pirelli. They'll do a forensic on the tire. Having said that, though, I have to agree with some of the posters above. 27k miles from a summer performance tire, especially the P Zero is rather unusual. I had the P Zero on my Audi RS5 and 10-12k miles is about all it was good for. I did occasionally drive it hard in the canyons, but most of the driving was just normal around town and highway driving. The RS5 also was not a torque monster like an AMG, but I still get about the same mileage out of the PS4S on my C63 now.
PFL205.064 with M276.823 (Oil pump solenoid defeated)
Wait a minute, if I understood this correctly, this was a W206 C 300 that had 27K miles? If so, why does it have summer performance tires? I thought they all have all-season run-flats?
Wait a minute, if I understood this correctly, this was a W206 C 300 that had 27K miles? If so, why does it have summer performance tires? I thought they all have all-season run-flats?
19" comes with summer performance tires. R01 is code for summer performance tires.
I agree however, that some things don't seem to add up in this story. For starters, 25k mileage warranty on a P Zero summer performance doesn't seem right. On a staggered setup where you can't rotate the tires, the warranties are cut in half. Michelin for example only warranties their performance tires for 15k miles with a staggered setup. 25k for the P Zero summer performance tire isn't happening. Maybe the P Zero All Season, but not the summer.
PFL205.064 with M276.823 (Oil pump solenoid defeated)
Originally Posted by superswiss
I agree however, that some things don't seem to add up in this story. For starters, 25k mileage warranty on a P Zero summer performance doesn't seem right. On a staggered setup where you can't rotate the tires, the warranties are cut in half. Michelin for example only warranties their performance tires for 15k miles with a staggered setup. 25k for the P Zero summer performance tire isn't happening. Maybe the P Zero All Season, but not the summer.
This also puts the tire pressure back into question as All Season and Summer performance tires typically call for different tire pressures. For reference here's the sticker from my C63S. M+S (aka all-season) requires higher tire pressures than the corresponding OE performance tires for the same speed range. M+S is 130 mph max. There are different P Zero tires.
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