Quote:
Originally Posted by CLH
Happy to help!
285/30-18 will fit all the way around (it’s been done, but not by me). Whether it’s a better choice up front than the 275 is not clear. The RE71R probably has a stiff-enough sidewall to be OK pinched that much, but the difference in footprint is going to be really small. At my level of skill I doubt it would make any tangible difference  |
Popping in to see folks interest in BS in the M2. I've been competing in a E92 M3 in FS the last three years with 19x9/18x10 setup. I've got two full sets of Apex wheels plus two additional fronts and run the Dinan adjustable front sway bar. Re: tire widths on 18" wheels -- here is my thoughts. I've run 265 square (when 275 RE71R's were on back order in 2015 briefly) 265/275, 275 square and 285/30's square. For my application, my max speed in 2nd on 275's is 68~ and 65.5~ on 285's.
My most preferred setup is 275 or 285 squared as having the wider fronts helps with understeer. 285's are very confidence inspiring in turn with virtually no tire deflection due to the shorter, stiffer sidewall, and will give you snappier gearing on slower, low speed dig out oriented courses as it has a 24.8" diameter, but suffer on Nat'l courses where speeds can easily surpass 65 mph requiring up and down shifts which makes it slower. Furthermore, the shorter sidewall will cause some unsettling of the car on bumpier surfaces, resulting in brief loss of traction at the extremes. The 285/30-18's are a total bitch for tire installers to mount on 9" fronts. Many shops can not get them on. I was one of three competitors out of 47 in FS at Nat's last year who had them as many could not get them mounted. Evidently, once they are mounted, they are easier to remount. If you pursue this, contact me and I'll explain what my installer did to get them on.
The 275's will have slightly less mid-apex grip up front but still pretty stout, and be a little less snappy in terms of dig out gearing (25.6"), but will be less prone to need for upshift and have less issue with being unsettled as the taller sidewalls will absorb surface imperfections far better than 285's with less issue. This very well may make them the faster/better choice overall as the pros may outweigh the cons. Last year, I committed to 285 square on my two sets of tires I was going to use, and felt that for everywhere except Nat'l events, it paid off, but at Nat's I ran into gearing issues which could me. I trophied in 12th but was .5 out of 5th over two days (easily could have been .8 faster the first day) and ran into rev limiter both days which probably cost me another .5-1 sec. I've finished as high as 5th. The winner last year had 285's front/275's rear which was an interesting gamble. I may try that this year I as I still have a pretty fresh set sitting around from Nat's.