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2010 2011 BMW 5 Series Forum F10 Need feedback on tire diameters for 20" Staggered on xdrive |
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03-10-2021, 05:41 PM | #1 |
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Need feedback on tire diameters for 20" Staggered on xdrive
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? |
03-11-2021, 10:50 AM | #2 |
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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. |
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03-11-2021, 12:04 PM | #3 |
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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 |
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03-11-2021, 02:43 PM | #4 | |
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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) |
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03-11-2021, 02:45 PM | #5 |
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Those sizes are perfectly matched, but I'm not seeing 295/30/20's available from Tirerack. Where did you buy yours from?
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03-11-2021, 03:18 PM | #6 |
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[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? Last edited by 2013F10; 03-11-2021 at 03:44 PM.. Reason: Was wrong |
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03-11-2021, 03:58 PM | #7 | |
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03-13-2021, 08:46 AM | #8 | |
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[QUOTE=2013F10;27332097]
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03-19-2021, 08:21 AM | #9 |
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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. Last edited by 2013F10; 03-19-2021 at 09:29 AM.. |
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03-20-2021, 02:16 AM | #10 | |
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