Help with tyre sizes

[stig1983]

Ive bought KW coilovers and also some speedline alloys 20x10







they've got stupid tyres on at min 235/30/20 with a ridiculous stretch.

Not quite sure what tyres to go with to get the best look when its sat low and wheres best to get them from at a good price.



Thanks Adam

[tintin]

you could try here:

http://www.carbibles.com/tyre_size_calculators.html

I've only had a quick play with this, but it seems to cover most questions - see the foot of the webpage for the ideal tyre size section. Let me know if it works

[Architex_mA8tey]

From memory you might struggle to get 20 x 10 wheels on the fronts due to impeding the suspension members, take a look at Audipages HERE for some advice. The widest Ive seen at the front is 275's on a 9 inch wheel so 10 inch is a huge increase, may be a suck it and see job so try bolting the wheel on before you buy the front tyres! Rears can go much wider, my rears are 295 25 21 on 10.5 inch wheels whereas the fronts are 255 30 21 on a 9 inch wheel.
The final editions are 9 inch wheels and Ive got 275's on mine all around when I put them on but if youre lowering the front down like I have on coilovers then be prepared for some adjusting or put up with some rubbing!

[stig1983]

Cheers for your advice mate hoping they fit as don't really want to start messing about with arches. Could always have the wheels adjusted to 9". Know a mate who has had it done to get 20"s on his A3 sport back. What exactly have you done to yours with regards to suspension. Was maybe thinking a 255/35/20 tyre for the front? I have no idea as never had wheels this big, I've only ever owned Corrado's and golfs

[Architex_mA8tey]

Assuming your tyres are currently 245 45 18 then the new ones will compare as follows on diameter/rolling radius -





The new tyres/wheels would be just slightly larger with a difference in radius of 0.2 inches or 4.4 mm

Its not the tyre size that worries me is the wheel width - a 10 inch wheel I think will still give you problems so you may need to narrow the wheels or get a swap on 2 of them to a 9 inch wheel and then fit staggered tyre sizes like I have

[stig1983]

Thanks again all info greatly appreciated going to test fit on Thursday so will let you know. Hope i don't have to do to much messing about really want these wheels on ASAP. If they don't fit and anybody want to swap 2 10's for 9's let me know

[Architex_mA8tey]

Suspension wise I have fitted coil-overs to the front only and the rears are stock quattro sport suspension which from memory is the same as the S8 and 20mm lower than standard A8, but if my rear wheels weren't so wide then I would have looked at perhaps lowering the rear a little and the front even more. For day to day use and still getting over speed bumps etc mine is as low as I dare really with the wheels fitted. Perversely the 20" final edition wheels I also have as my other set are very slightly bigger on diameter/radius than the Kahn wheels and more likely to rub at the front, and really this is where you have to suck it and see and tweak the coilover's height to suit. It would be possible on yours to lower the rear some and tuck the top of the wheels into the arch by adjusting the rear wheel camber if you wanted.

[stig1983]

And I take it spacers or adapters will only make the clearance worse?

[Architex_mA8tey]

The tyres you have on your new wheels at the moment look like this against
your existing combination -



Overall diameter about 14mm smaller than existing and so your speedo will read about 4.2% faster than you are actually doing. Still not sure the fronts will fit (well they may fit but they wont turn full lock either way without fouling the suspension arms)

[Architex_mA8tey]

Originally Posted by stig1983

And I take it spacers or adapters will only make the clearance worse?

You can space the wheel away from the arms but then as you lower the front on the coilovers you will get to a point where you are rubbing the inside top of the wheel arch liner, like I say its an exercise in playing around until you get it where it works and you are happy with the look/drop at the front. It also depends on the ET of each of the sets of wheels etc

Rears should be fine. You'll get an idea of spacer possibilities when youve fitted the wheel and see how far you could possibly move it but with 10" wheels it may still be hard to get it where you need/want it at the front - but good luck!