[2013F10]

My 2013 535ix has 20" 343M wheels from an M5. My previous tires were Continental Sport Contacts that were great tires, but I always hated how far the rim stuck out from the sidewall in the front so I'm looking for a wider front tire but obviously need to keep AWD in mind when choosing a set. I'm looking at getting a set of Michelin Pilot Sport A/S 3's and need feedback on sizes.

My rear tires are nearly bald (maybe 2/32" tread left) but my fronts still have 7/32" tread left, which means the rear tires wear faster and are now much smaller diameter than the front tires.

Others have used the following:
Front: 255/35ZR20 (27” diameter, 770 revs/mile)
Rear: 285/30ZR20 (26.8”, 777 revs/mile)

With this setup, the rear tires are already 0.2" smaller in diameter than the front, and the rear wears out MUCH faster than the fronts so I would end up with a large difference in diameter again.

I thought about this size combo for larger diameter rear tires, which would wear down to match the front tires better.
Front: 255/35ZR20 (27” diameter, 770 revs/mile)
Rear: 275/35ZR20 (27.6”, 755 revs/mile)

Has anyone used this size combo?

[Surly73]

Be very careful.

"Tire size calculators" use nominal sizes for the numbers you enter. There is a wider-than-you-would-like acceptable range of tolerance around those nominal sizes. Worse, if the tire manufacturer doesn't consider the sizes you've picked as a "set" for staggered use, the two sizes could be at opposite ends of the tolerance range.

If you can get "star" rated tires or similar by choosing popular BMW staggered pairings, they are made so that rolling circumference is within tolerance for X-Drive.

It wasn't in an AWD application but I've "been there, done that" and despite thumbs up from tire size calculators and other owners with a size combination on a past car, it looked odd because of opposing tolerances. At least there was no transfer case to destroy in that case.

[Hoa]

I would recommend the following:

255/35/20 Front
295/30/20 Rear

I have xDrive. I have been swapping between that and my 19" depending on the season.

245/40/19 Front
275/35/19 Rear

[2013F10]

Originally Posted by Surly73

Be very careful.

"Tire size calculators" use nominal sizes for the numbers you enter. There is a wider-than-you-would-like acceptable range of tolerance around those nominal sizes. Worse, if the tire manufacturer doesn't consider the sizes you've picked as a "set" for staggered use, the two sizes could be at opposite ends of the tolerance range.

If you can get "star" rated tires or similar by choosing popular BMW staggered pairings, they are made so that rolling circumference is within tolerance for X-Drive.

It wasn't in an AWD application but I've "been there, done that" and despite thumbs up from tire size calculators and other owners with a size combination on a past car, it looked odd because of opposing tolerances. At least there was no transfer case to destroy in that case.

Thanks for being direct, personal opinions are too subjective so I'm looking for hard facts.

It sounds like if I go with the 255 fronts (nominal diameter difference of 1.1%) I'll be well outside the safe range for xdrive as the rears wear and the difference grows. As you said, if the fronts and rears are at opposite ends of the tolerance range the difference would be even greater.

It sounds like Tirerack's recommendation (What I'm running now) is my best option:
Front: 245/35ZR20 (26.8” diameter, 777 revs/mile)
Rear: 285/30ZR20 (26.8”, 777 revs/mile)

[2013F10]

Originally Posted by Hoa

I would recommend the following:

255/35/20 Front
295/30/20 Rear

I have xDrive. I have been swapping between that and my 19" depending on the season.

245/40/19 Front
275/35/19 Rear

Those sizes are perfectly matched, but I'm not seeing 295/30/20's available from Tirerack. Where did you buy yours from?

[2013F10]

[QUOTE=Hoa;27331157]I would recommend the following:

255/35/20 Front
295/30/20 Rear

Found Continental DWS's on Tirerack by searching by size. The front are DWS's, the rears are DWS Plus's. The look the same and have the same ratings.

EDIT: Fronts are W rated, rears are Y. Back to the drawing board.
EDIT 2: What brand are you running?

[Hoa]

Originally Posted by 2013F10

Those sizes are perfectly matched, but I'm not seeing 295/30/20's available from Tirerack. Where did you buy yours from?

I got Michelin 4S from discount tire

[Blue Angel]

[QUOTE=2013F10;27332097]

Originally Posted by Hoa

I would recommend the following:

255/35/20 Front
295/30/20 Rear

Found Continental DWS's on Tirerack by searching by size. The front are DWS's, the rears are DWS Plus's. The look the same and have the same ratings.

EDIT: Fronts are W rated, rears are Y. Back to the drawing board.
EDIT 2: What brand are you running?

295/30-20 on 343 on a non-M5 F10 is almost sure to rub, based on my memory when I looked into it anyway. I seem to remember the 245/285 combo being about as much tire you can use with M5 wheels on a regular F10.

[2013F10]

Originally Posted by Hoa

I would recommend the following:

255/35/20 Front
295/30/20 Rear

A couple of questions since the latest comment says there may be some rubbing.

-Do you experience any rubbing at all?
-Is your car lowered? I'm planning on lowering the rear about an inch.

Thanks, I went ahead and took your suggestion but have to wait a week to have the tires installed.

[Hoa]

Originally Posted by 2013F10

A couple of questions since the latest comment says there may be some rubbing.

-Do you experience any rubbing at all?
-Is your car lowered? I'm planning on lowering the rear about an inch.

Thanks, I went ahead and took your suggestion but have to wait a week to have the tires installed.

No, mines does not rub. Many others have stock M5 size (265 front, 295 Rear) and did not rub either. I am not lowered.