definitive tire, wheel, and offset thread

[kismetcapitan]

ok, I'm insomniated and have decided to do a little research.

for starters: rim width vs tire size
8.5" = 255
9" = 265
9.5" = 275
10" = 285 (has 285s been mounted before??)

tire sizes within acceptable range:
255/40R18
265/40R18 (larger than stock)
265/35R18 (smaller than stock)
285/35R18 (smaller than stock)

255/35R19 (same as stock)
265/35R19 (larger than stock)
275/30R19 (smaller than stock)
285/30R19 (smaller than stock)

with 8.5" width:
stock offset = 30mm, 20mm maximum with front fender rolling

by doing some math...
9" width = maximum offset 27mm
9.5" = maximum offset 34mm
10" = maximum offset 41mm

Do these numbers look right? I'm no tire expert, but having a chart like this would be immensely useful.

I don't know at what point filing down the nub on the inside suspension arm is required.

[HT MOtorsport]

Here's a useful online calculator for offset too http://www.1010tires.com/WheelOffsetCalculator.asp

Once my new wheels and tires get here and I see if they fit Ill add the info on those.

[NSU RS6]

I am running 19 x 9 et 33 S5 Speedlines in the C6 RS6 style. I applied a 8mm Spacer/Adapter to fit the larger hubcentric bore of the later model Audi wheel, and which also put me at an offset of et 25. The tires are 255/35-19 Michelin Pilot Super Sport. I am very happy with the set up, although I might be tempted to go 265/35/19 when the time comes. The 255/35-19 tires are slightly "stretched" on a 9" wide wheel - but there are quite a few people who go for this look, sometimes to the extremes. 265 would add a little curb protection.