18" RS4s on a 2001 A4

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imported_topcat28

Guest
Yet another question... Sorry if this has been covered before. Read the sticky about wheels and tyres, but still confused...!

My 2.5 TDi Q has 17" 5 spokes on it (I assume from new). Thinking of some RS4 type 18" wheels, probably 8.5" wide?

Do I need to put very low profile tyres on them to maintain the overall circumference? If not, what sort of size would I be looking at? Also, does it not affect the instruments etc?

Oh, and what should the offset be? I assume it should be less than the current 45 - perhaps 20 if they're an inch wider?

Thanks in advance...
 
Okay getting really confused now! Have read various posts and tried to get my head around the offset calculations...

Less reliable a source for information I know, but some of the listings on eBay seem to contradict each other as well!

I've seen a set of 18" oe RS4s that I quite fancy. They're 8.5" wide and ET20. So, will they fit my 2001 A4?!
 
are we talking 2001 b5 or b6?

for b5 nope won`t fit. ET20 is too much. you need et35ish
 
Sorry, should have said, B6.

Must admit, assumed they would fit a B5, as I assumed that they'd come off an RS4! But I guess the wheels were made for other cars - I've seen mention of this size on an A6...

The 17 x 7.5 wheels I've got are ET35, but thought the wider 8.5" wheel would need a different offset. But I'm so confused I don't even know if its more or less, let alone whether the 20 is correct!
 
you'll be good with 8.5" but you'll need 235 tyres as i've recently found out, if you use 225 tyres they'll be running stretched which looks good but side wall is easily damaged. however if you use 8.0" wheels 225 will be fine

et20 on a et45 car is huge amount to stick out, maybe trouble with mot rules? and they will be out far enough to catch your wheel arch

et35 is just about right , gives the car a good stance not too far out

hope that is a little clearer..

summary

use et 35

235/40/18 tyres on 8.5"
225/40/18 tyres on 8.0"

i think speedo knock out is negligble as they're way out any way, mine on stock wheels was 5mph faster on the motorway, some more than that, use gps for speed guage.
 
I Have 18" RS6's fitted and had 235 / 40's tyres on BUT.... they shredded the intter plastic wheelarch thingys, so I have changed them to 225 / 40's and seem fine!
 
Well, finally got some RS4s... Guess I could have got replicas fairly easily, but patience and eBay yielded a set of original wheels with virtually new Pilot Sports for about an extra fifty quid - so pretty chuffed...!

Wheels are ET43 - which made sense to me. Wheel is an extra 1/2 inch wide, so half of 12.5 on the offset...? Maybe I still don't get it...!

Anyway, they fit and don't seem to rub. And, in my opinion at least, look pretty cool.

Attempted pic: RS4s

Once again, thanks for all of the help and advice.