Offsets/tire sizes/fitment questions.

Tsuyoi · 12-08-2013, 03:52 PM

So I'm swapping out my tires soon, and I had some concerns about the offset/tire sizes.

I'm currently on Star Spoke Style 396 - 18" 18x8 225/45/18 front and rear, but the tires I want (Michelin Pilot Sport A/S) only come in 245/40/18 minimum. I'm not sure what the default offsets are (I think ET34), but would that cause an issue if I put 245/40 tires all around? I know zero about wheels/tires and offsets, so I don't know if changing only the tire and not the wheel would affect if the offset is correct or not.

After reading the following review http://www.tirerack.com/tires/tests/...&affiliate=FH3

I picked the Michelins for their best overall balance between comfort and snow/wet conditions. However if the 245 size is going to cause rubbing/stick out a lot I may have to go with the Bridgestone Potenzas instead, since they actually come in 225/45 size.

Any help appreciated!

2blu · 12-08-2013, 04:02 PM

As far as rubbing goes, you should be ok. The tire will be 20mm wider overall, so 10mm further on each side of the rim, shouldn't cause any headaches by my guess.

It's recommended to stay within 3% of the OEM overall diameter. Your overall diameter in this case would change by 0.18 inches, so you are fine in that department.

I haven't used this tire setup nor have I searched to see if anyone has, but by my guess, you will be fine.

.BMW. · 12-09-2013, 08:28 AM

Quote:

Originally Posted by Tsuyoi

I'm currently on Star Spoke Style 396 - 18" 18x8 225/45/18 front and rear, but the tires I want (Michelin Pilot Sport A/S) only come in 245/40/18 minimum. I'm not sure what the default offsets are (I think ET34), but would that cause an issue if I put 245/40 tires all around? I know zero about wheels/tires and offsets, so I don't know if changing only the tire and not the wheel would affect if the offset is correct or not.

It will be fine with 245 square!

Take a look in the linked threads, the first with a square 245 setup with Bridgestone RE-11A and the second with Michelin PSS 245/40-18 rear.

Bridgestone RE-11A 245/40-18: f30post.com

Michelin PSS 245/40-18 (rear): f30post.com

12-08-2013, 03:52 PM	#1
Tsuyoi Lieutenant 34 Rep 568 Posts Drives: 2013 F30 328i Join Date: Nov 2012 Location: New York iTrader: (0)	Offsets/tire sizes/fitment questions. So I'm swapping out my tires soon, and I had some concerns about the offset/tire sizes. I'm currently on Star Spoke Style 396 - 18" 18x8 225/45/18 front and rear, but the tires I want (Michelin Pilot Sport A/S) only come in 245/40/18 minimum. I'm not sure what the default offsets are (I think ET34), but would that cause an issue if I put 245/40 tires all around? I know zero about wheels/tires and offsets, so I don't know if changing only the tire and not the wheel would affect if the offset is correct or not. After reading the following review http://www.tirerack.com/tires/tests/...&affiliate=FH3 I picked the Michelins for their best overall balance between comfort and snow/wet conditions. However if the 245 size is going to cause rubbing/stick out a lot I may have to go with the Bridgestone Potenzas instead, since they actually come in 225/45 size. Any help appreciated! Last edited by Tsuyoi; 12-08-2013 at 03:57 PM..
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12-08-2013, 04:02 PM	#2
2blu Captain 197 Rep 923 Posts Drives: 540i XDrive ///M Sport Join Date: Oct 2013 Location: Montreal iTrader: (1)	As far as rubbing goes, you should be ok. The tire will be 20mm wider overall, so 10mm further on each side of the rim, shouldn't cause any headaches by my guess. It's recommended to stay within 3% of the OEM overall diameter. Your overall diameter in this case would change by 0.18 inches, so you are fine in that department. I haven't used this tire setup nor have I searched to see if anyone has, but by my guess, you will be fine. __________________ GONE: '13 335i X-drive ///M-Sport \| GONE: '16 340i X-Drive ///M-Sport \| GONE: '18 540iX-Drive ///M-Sport \| NOW: '20 X3///M
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