E60 2008 535i 6MT with Sport Suspension. Original equipment is staggered 245/40-18 in front and 275/35-18 in rear. When the current tires are shot I'd like to go to a square set up but with slightly wider tires than the 245/40-18 original equipment non-sport set up. Looks like the closest set ups in terms of tire diameter are either: 265/35-18, 255/35-19, 265/30-19 or 275/30-19. I assume the 275's (and possibly 265's) are too wide to put on front, so that leaves the other three options (assuming wheel offsets are appropriate). My questions are: 1) has anybody made a similar swap with any of these sizes and how do you like it? 2) are there any issues going wider than the factory 245 set up in the normal square configuration? 3) or do I stick with a 245 and just go to 19" wheels, i.e. would a 245/35-19 simply be the best set up?
I don't have an E60, so can't be definitive about anything. First off, see what Tirerack.com shows - they're conservative in their fitment info, so you can have reasonably high confidence about whatever they recommend. Might be worth a call, they may have more specific information in their systems for reference vs. what their site shows. I've no idea if 275's could fit on the front for instance, but, on my E92, the optional rear 255's will fit on the front, but no way to know if what's true on that model carries over to the completely different 5'er. Might also be worth seeing if Apex wheels (https://www.apexraceparts.com/) has any suggestions on what wider tire can fit the E60 front. Since 255's aren't much wider, I wonder if they would be an okay front fit clearing in the front for a square setup without losing as much width on the rear... assuming the tires you like are available in an appropriate size. This is helpful with evaluating different sizes: https://www.rimsntires.com/specspro.jsp On the downsides of larger dia. wheels are less tire sidewall, which means less sidewall to absorb bumps and serve as rim protection (so more risk of suffering impact damage), and feeling bumps/road imperfections a bit more. To minimize the weight penalty of larger wheels, consider the weight of the wheel and prioritizing wheel lightness.
