My current wheel and tire setup is 245/35/17 GS-D3 rear and 235/40/17 front on staggered bmw LTW 17x7.5-17x8.5. My tires are old and hard and it is difficult to maintain traction while driving aggresively. My last auto-X really showed me that the tires were done. So I am looking at star spec's and yes I have read the debate abou the R-S3 and the Star Spec's and given that I live where it gets cold and sometimes rains I am going for star specs. My question is how big do you think I can go tire wise considering that I have maybe 5-10 mm clearance in front of and behind my current setup. Normaly I would just pull the trigger and figure it out trial and error style but tires are not cheap so I seek the guidance of those who may have come before me. My arches are pulled and lips are rolled to clear my current setup.
I was originally just going to try the 245/40/17 rear but I hear they are wide as shit. According to tirerack.com there is only a .1 difference in section width vs my current setup but the star spec's have no listed tread width.
I am currently running a 12mm spacer up front to clear the coilover adjuster with the current 234/40/17. I can order a new spacer as my studs will support up to 18 mm of spacer but I dont want to just blindly throw tire size at a grip issue.
I am not sure how much more I could roll or pull without destroying my fenders. Thanks in advance for any input. Current setup pics.

I was originally just going to try the 245/40/17 rear but I hear they are wide as shit. According to tirerack.com there is only a .1 difference in section width vs my current setup but the star spec's have no listed tread width.
I am currently running a 12mm spacer up front to clear the coilover adjuster with the current 234/40/17. I can order a new spacer as my studs will support up to 18 mm of spacer but I dont want to just blindly throw tire size at a grip issue.
I am not sure how much more I could roll or pull without destroying my fenders. Thanks in advance for any input. Current setup pics.

