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Feedback on R-tire/Wheel setup

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Hi,

I am planning to upgrade from the OEM wheels & tires to a race setup. My choices for larges dimension R tires here in Europe is rather narrow and it's costly as hell to import from US, so here's what I have been able to piece together:

Front:
Kumho V70A Ecsta Hard compound 265/35 R18 on 18x9.5" rims

Rear:
Kumho V70A Ecsta Hard compound 305/30 R18 on 18x11" rims

I have done a few track days on the OEM tires and find that the shock rating that fits my driving is 5F/4R and then the car is pretty well balanced mid corner.

So, to the questions:

1. Will this setup fit? The wheel diam is 1.5" smaller than OEM, but I figure that is only positive since CG will be lower. This will be a track only setup.

2. Which wheel offset (ET) would be OK?

3. Will I experience more considerably more understeer than with OEM considering I could go 5F/5R on the shocks?

Thanks,

/Swede
 

Grant 302

basic and well known psychic
1. Should work and be fine, just might look a little short/small if you're at the stock ride height.

2. For that front, I think you can run between ET +35 and +45 or so. Might be able to run less than +35 if you run more camber. For the rear, I think you need to be close to +50 and go for more if you have the sway bar clearance. I'd shoot for +54 or +55 if you can get it to fit and not rub either the sway or tires on the fender wells. +50 would poke out a bit, but it shouldn't matter with such a short tire and stock springs.

3. Without seeing the tread widths, I'd expect understeer with the stock suspension. Might be able to dial it out with tire pressure and shocks, but I doubt it unless its a wide 265 and narrow 305.
 

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