Quote:
Originally Posted by r4gs
alright, thanks to nikki, verified tt 9.5" et35 will clear the inside of the rear wheel wells.  question i'm having now is, front diameter is going to be 25.4", and rear is going to be 26.35". how significant is this 0.95" difference in tire diameters going to affect stance, handling, speedo error etc, if any?
am looking at a local set of m6 reps - 18x8.5 et35 fronts with 235/40 ps2's, 18x9.5 et35 rears with 265/40 ps2's. $1200 picked up sounds reasonable? 1 year old, 6000 miles, minor curb rash on one of them, no bends, cracks, peeling etc. |
I rely pretty heavily on
http://www.1010tires.com/TireSizeCalculator.asp for making tire comparisons. It's a pretty handy calculator. I didn't look to see what calculator is referenced in the e90post link above, maybe it's the same or similar. 265/40 is stock E90 M3 tire size, wouldn't be too much different from our stock tire - little taller side wall, some people like that. The 235/40 is a down size from the stock E90 M3 front tire (which is a 245/40). I's probably end up doing something different with the front in place of that 235/40.
I think nearly 1" diameter difference in tire size front to back will be noticable visually and might look a little weird. Stock 255/40/18 tires all run right at 26" diameter, give or take maybe 0.1". Even though the fronts clearly will not affect the speedo, you can't make too drastic of changes up there because it could potentially affect DSC.
In general, I think a half inch or less difference in diameter, front to back, would be desirable from an appearance point of view. Beyond that, it's just a matter of comparing any desired tire sizes to what stock is just to keep diameter close for the sake of not screwing with the speedo too much or potentially triggering DSC issues.