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Bill Verburg Bill Verburg is online now
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Quote:
Originally Posted by DennisMenace View Post
Hi Bill. Thanks a lot for your reply. Totally makes sense. I plan to run a-b at around 160 mm in the front with raised spindles. Isn’t the first number (95mm) the more critical number as it puts the wheel outwards towards the fender?

Thanks a lot,
Dennis
You certainly want the f/s spec to be not much larger than ~90mm but there is a grey area where shorter tire though it stocks further out still clears the fender

The best way to get the f/s down w/ a 225/xx tire is to use a larger ET wheel

for 8s you would want ET27-28 as the best compromise between inner and outer clearance

for 7s though the wheel is narrower and pinches the tire sidewalls toward the wheel center more a bit higher ET is still desirable say ~ 25-26

Unfortunately, if you want 15" Fuchs you are stuck w/ 7 ET23.3 or 6 ET 36

The taller 205/55 x16 on a 7ET23.3 is often a problem at the lip the shorter 205/55 x15 on a 7ET23.3 is not because it is shorter.

a 225/50 x15 is still relatively short and thus does give some breathing room even w/ the f/s above 90mm.

Obviously you ride heigh is going to affect this situation as well.

I used to primarily look at a-b but find that it obscures the issue to a certain extent

b all by itself is the real measure of height, a varies w/ the tires spec
a 205/50 x15 R888 has an a of ~ 285mm
a225/50 x15 R888 has an a of ~295mm

so for the same b(aka ride height), a - b for the 225 will be larger by ~ 10mm

so if you have a -b w/ 225s of 160, that's the equivalent of a - b of 150 w/ 205/50

and you will have 10mm less height clearance at the lip.
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Bill Verburg
'76 Carrera 3.6RS(nee C3/hotrod), '95 993RS/CS(clone)
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