Tire size?

[MrHarris]

I'm getting aftermarket rims, 19x9 and 19x10. I want 255's up front and 275's in the rear. What size tires would I get to keep the factory speedo/look?

[GregW / Oregon]

Originally Posted by MrHarris

I'm getting aftermarket rims, 19x9 and 19x10. I want 255's up front and 275's in the rear. What size tires would I get to keep the factory speedo/look?

Revolutions per mile (which is a more precise indication of overall diameter) is the easist data to look at (following is for PS2s). Stock 245/35s & 265/35s are 807 & 790 revs/mile, respectively. 255/35s for the front are in the ballpark at 799. For the rear, 275/35s are at 783 revs/mile. Both of those are only 1% larger than stock, so should be fine. They should actually make the speedometer more accurate, as it's a little optimistic.

You could also go 265/30 F (822) and 285/30 rear (799) with the right offsets, though these are slightly smaller OD. Check with your wheel manufacturer for another opinion.

[MrHarris]

I thought I needed 255/35 and 275/30?

[kmarei]

go here and plug in the numbers
http://www.e90post.com/forums/forumdisplay.php?f=12
the front OEM wheels are 8.5" width and an offset of 29
rear are 9.5" offset 23

[GregW / Oregon]

Originally Posted by MrHarris

I thought I needed 255/35 and 275/30?

275/30s are 3% smaller than the stock rears, vs. 1% larger for the 35s. By smaller, I mean circumference, not diameter, which is the important factor. You decide.