Hey guys
I know theres a bunch of calculation threads out there, but this one is slightly different. I've currently got the JCW R105's @ 18x7" with 205/40/18's lowered on Mach V springs, which would be (if im correct) 205/.40/25.4 = sidewall inches, +18" will give the total 'wheel + tire' height, right? thus, 21.23"

I'm now looking for either a 16 or 17" wheel with new tire. @ 17", I'm looking at either a 215/45/17 (20.81"), or a 225/45/17 (20.98"), or something similar. With a lower tire+wheel height, I'm looking at more "wheel gap" and/or "clearance" correct? Thus, to keep the same wheel gap stance I've got going, I'd want something as close to the 21.23" I've got calculated now?

Please correct me if I'm wrong. I'm looking at a 17" x7 Ultraleggera, but also like the superturismo gt's, but they are much heavier ftl (i know heavy wheels having these JCW's =p )

Any input would be appreciated guys, thanks in advance

 

Tire sidewall x2

Tire plus rim should be about 24.3-24.5"

 

I always use this calculator. It's excellent.

--Dan
Mach V

 

I prefer this one:

http://www.rimsntires.com/rt_specs.jsp

It allows you to change the rim sizes, widths, and offsets. It lists out compatible tire sizes, and lets you put tires on the rims to see a visualization. It can even estimate rubbing and other issues.

 

The one from rimsntires is great. That is the one I always use.