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[gkgsvensson]

Hi all, trying to get some winter tires for my M3 on stock 18” wheels. I really like the Michelin x-ice snows but they don’t have the rear oem size (265/40 r18). I was wondering about running the 255/45 but the diameter is about half an inch larger an im worried it will mess up DSC (assuming I run stock 245/40 fronts). Anyone actually run this size?

[M3SQRD]

You can probably getaway with it for a winter only setup. However, I’d recommend running a front tire with a similar diameter. The delta is enough to affect DSC especially with the rear having the larger diameter. DSC can handle a new front tire + completely worn rear tire. Not sure how it would react to a rear tire rotating slower than a front tire. However, I run 235/40-18 and 255/40-18 winter setup with no DSC issues.

[gkgsvensson]

Originally Posted by M3SQRD

You can probably getaway with it for a winter only setup. However, I’d recommend running a front tire with a similar diameter. The delta is enough to affect DSC especially with the rear having the larger diameter. DSC can handle a new front tire + completely worn rear tire. Not sure how it would react to a rear tire rotating slower than a front tire. However, I run 235/40-18 and 255/40-18 winter setup with no DSC issues.

How about running 235/45/18 up front and 255/45/18 in the rear? This set up results in about 2% larger rear diameter compared to front, which is nearly the same ratio as oem. The main difference is each tire is half an inch larger in overall diameter

https://tiresize.com/calculator/

[M3SQRD]

Originally Posted by gkgsvensson

How about running 235/45/18 up front and 255/45/18 in the rear? This set up results in about 2% larger rear diameter compared to front, which is nearly the same ratio as oem. The main difference is each tire is half an inch larger in overall diameter

https://tiresize.com/calculator/

Interesting. When I compare these sizes with stock, I get 1.5” and 1.3” front and rear, respectively, differences in diameter. However, this should still work if your car isn’t lowered and you don’t run spacers. The main issue is whether the front tire will rub on the fender li er especially at full lock. Do you know the widths and offsets of your winter wheels?

[gridworks]

Just throwing this out there, I also run 235/40 and 255/40 on 18s for the winter with no issues for what it's worth.

[gkgsvensson]

Originally Posted by M3SQRD

Interesting. When I compare these sizes with stock, I get 1.5” and 1.3” front and rear, respectively, differences in diameter. However, this should still work if your car isn’t lowered and you don’t run spacers. The main issue is whether the front tire will rub on the fender li er especially at full lock. Do you know the widths and offsets of your winter wheels?

Don’t know the offsets or widths off hand but these are the OEM 18s. I’m stock, no spacers. I’m willing to risk it I think. Will report my findings

[M3SQRD]

Originally Posted by gkgsvensson

Don’t know the offsets or widths off hand but these are the OEM 18s. I’m stock, no spacers. I’m willing to risk it I think. Will report my findings

Sounds good. The oem 18s are style 219M (made by BBS) in 18x8.5et29 and 18x9.5et23. Best looking oem wheel offered on the e9x m3.