quote:So for every 1” larger wheel size with a given tread width you’re looking at about a reduction of the side wall by 5. 16” = 45, 17” = 40, 18” = 35, 19” = 30 and 20” = 25.
Pretty much but this is only so because you have selected a tire width that is just shy of 10" wide, so when you take 5% of the width x2 and add it to the diameter you've changed the tire OD by about 1".
I've always found tire size designations to be a bit bizarre. Just so we're all on the same page, tire sizes as xxx/yy/*zz = width in mm/aspect ratio as % of width/*wheel diameter in inches, where * is speed rating. So side wall height is yy times xxx (in mm). So convert this to inches and add twice the side wall height to diameter and you're at tire OD.
As always Mike, your car looks great. As I follow the thread, there is one thing I'm wondering; if you're trying to maintain the same tire OD front and rear, what would wheel size have to do with how low you could set your ride height? With constant OD, in any case, the distance from the center of the wheel to the ground is the same, right?
Also, if you are at 3.5" of ground clearance on the street you're a braver man than me my friend. I have 345/30/ZR19 Rear and 265/35/ZR18 front but have installed GTS flares so have some more room. I don't recall ride height but you can get some big brake rotors inside an 18" front wheel. You can have a look at the linky to my gallery below to get a sense of wheel proportion.
Best Regards,
Kelly