Will 255/295 tires work for coupe?
Thread Starter
Junior Member
Joined: Aug 2020
Posts: 46
Likes: 7
From: Dallas, TX
'18 AMG C63S coupe
Will 255/295 tires work for coupe?
Hi y'all,
I just got back from Costco tires and they won't install the front 255/35/19 rear 295/30/20 Michelin PS4S for me. I ordered 295 in the rear because there weren't any 285 PS4S available in their system.
The manager came and said that I can only go with either 255/285 as OE, or both sized up as 265/295, since the car's traction control system will capture the difference in the spin speed from the wheels, and a change might mess the system up.
Then they also checked for me that they also don't have 265 front PS4S available.
Any idea or suggestions on whether 255/295 would work? If not I'm thinking about going to discount tires to reorder or bring those tires to an independent tire store.
I just got back from Costco tires and they won't install the front 255/35/19 rear 295/30/20 Michelin PS4S for me. I ordered 295 in the rear because there weren't any 285 PS4S available in their system.
The manager came and said that I can only go with either 255/285 as OE, or both sized up as 265/295, since the car's traction control system will capture the difference in the spin speed from the wheels, and a change might mess the system up.
Then they also checked for me that they also don't have 265 front PS4S available.
Any idea or suggestions on whether 255/295 would work? If not I'm thinking about going to discount tires to reorder or bring those tires to an independent tire store.
MBWorld Fanatic!
Joined: Dec 2013
Posts: 1,087
Likes: 509
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I suspect they're worrying about something that won't happen. On my C63 S sedan, for Cup 2 track tires I run 275/35 19" on the rear (that's an MO tire) instead of the stock 265/35 19". According to https://tiresize.com/comparison/, that's a 1.1% larger circumference ... and it works just fine. Your 295/30 20" has the same 1.1% larger circumference compared to the stock 285/30 20".
Looking at it another way, that's a difference between 26.7 and 27" diameter. If a tire has tread-wear that totals 5/32" that'll reduce the diameter by 10/32" or .3125" ... so, it's easy to predict that thousands of vehicles are running around with more than 1.1% difference between what would be the front/back circumference difference with stock/new tires ... and that's not even allowing for circumference stretching/shrinking during burnouts, high speed travel, braking and cornering forces, etc. and due to different tire pressures.
Clearly, the software on ABS/ESP/etc. systems needs to be able to account for such differences. I'd bet these systems can handle more like 5% difference. I'd go somewhere else to have them mounted.
Looking at it another way, that's a difference between 26.7 and 27" diameter. If a tire has tread-wear that totals 5/32" that'll reduce the diameter by 10/32" or .3125" ... so, it's easy to predict that thousands of vehicles are running around with more than 1.1% difference between what would be the front/back circumference difference with stock/new tires ... and that's not even allowing for circumference stretching/shrinking during burnouts, high speed travel, braking and cornering forces, etc. and due to different tire pressures.
Clearly, the software on ABS/ESP/etc. systems needs to be able to account for such differences. I'd bet these systems can handle more like 5% difference. I'd go somewhere else to have them mounted.
Junior Member
Joined: Apr 2018
Posts: 36
Likes: 6
2018 C63S Coupe
Hi y'all,
I just got back from Costco tires and they won't install the front 255/35/19 rear 295/30/20 Michelin PS4S for me. I ordered 295 in the rear because there weren't any 285 PS4S available in their system.
The manager came and said that I can only go with either 255/285 as OE, or both sized up as 265/295, since the car's traction control system will capture the difference in the spin speed from the wheels, and a change might mess the system up.
Then they also checked for me that they also don't have 265 front PS4S available.
Any idea or suggestions on whether 255/295 would work? If not I'm thinking about going to discount tires to reorder or bring those tires to an independent tire store.
I just got back from Costco tires and they won't install the front 255/35/19 rear 295/30/20 Michelin PS4S for me. I ordered 295 in the rear because there weren't any 285 PS4S available in their system.
The manager came and said that I can only go with either 255/285 as OE, or both sized up as 265/295, since the car's traction control system will capture the difference in the spin speed from the wheels, and a change might mess the system up.
Then they also checked for me that they also don't have 265 front PS4S available.
Any idea or suggestions on whether 255/295 would work? If not I'm thinking about going to discount tires to reorder or bring those tires to an independent tire store.
Running this exact set up and works great.
Love the beefier look of 295 too. Kind of want to go 305 next.
Thread Starter
Junior Member
Joined: Aug 2020
Posts: 46
Likes: 7
From: Dallas, TX
'18 AMG C63S coupe
I suspect they're worrying about something that won't happen. On my C63 S sedan, for Cup 2 track tires I run 275/35 19" on the rear (that's an MO tire) instead of the stock 265/35 19". According to https://tiresize.com/comparison/, that's a 1.1% larger circumference ... and it works just fine. Your 295/30 20" has the same 1.1% larger circumference compared to the stock 285/30 20".
Looking at it another way, that's a difference between 26.7 and 27" diameter. If a tire has tread-wear that totals 5/32" that'll reduce the diameter by 10/32" or .3125" ... so, it's easy to predict that thousands of vehicles are running around with more than 1.1% difference between what would be the front/back circumference difference with stock/new tires ... and that's not even allowing for circumference stretching/shrinking during burnouts, high speed travel, braking and cornering forces, etc. and due to different tire pressures.
Clearly, the software on ABS/ESP/etc. systems needs to be able to account for such differences. I'd bet these systems can handle more like 5% difference. I'd go somewhere else to have them mounted.
Looking at it another way, that's a difference between 26.7 and 27" diameter. If a tire has tread-wear that totals 5/32" that'll reduce the diameter by 10/32" or .3125" ... so, it's easy to predict that thousands of vehicles are running around with more than 1.1% difference between what would be the front/back circumference difference with stock/new tires ... and that's not even allowing for circumference stretching/shrinking during burnouts, high speed travel, braking and cornering forces, etc. and due to different tire pressures.
Clearly, the software on ABS/ESP/etc. systems needs to be able to account for such differences. I'd bet these systems can handle more like 5% difference. I'd go somewhere else to have them mounted.
MBWorld Fanatic!
Joined: Aug 2012
Posts: 1,218
Likes: 315
From: Pearland, Tx
2020 AMG GTC Coupe & 2018 Macan Turbo
Look here:
https://tiresize.com/calculator/
You want the Comparsison tab at the top. Put in existing tire size and then you think you want. It will tell you speed odo error and everything else.
https://tiresize.com/calculator/
You want the Comparsison tab at the top. Put in existing tire size and then you think you want. It will tell you speed odo error and everything else.
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MBWorld Fanatic!
Joined: Aug 2012
Posts: 1,218
Likes: 315
From: Pearland, Tx
2020 AMG GTC Coupe & 2018 Macan Turbo
I just had Conti Extreme Contact Sport's with 255's and 285's today with an alignment. Will be picking it up in the morning to "heat cycle" the tires on the way home.
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