Do I need to replace both front tyres?

[S4WON]

As title suggests. Or can i just replace one?

I've carried out a bit of research and depending on who you speak to, it's either all 4, both on same axle or just the one as long as exact same tyre.

Soooo, which is it?

The thread with the most technical detail which supports i only need to change one is this

http://www.ozaudi.com/forums/general-lo ... 2-a-2.html

Check out post #17.

The summary is as long as you are within 3% of rolling diameter its fine. And as he shows the same tyre with 7mm or 1.5mm is still only 1.5% difference so I'm thinking i just change one and it'll be fine.

Anyone else have more to add?

Thanks

[SuprSi]

The difference in grip would be a big factor too I'd imagine, a new tyre would have a lot more grip than one that's done quite a lot of miles already.

If one tyre's still fairly new then I'd use it, but otherwise I'd change the pair and ebay the better tyre or keep as a spare.

[S4WON]

Thanks Si. Lepsons seem to think they can work some magic on the rim, so maybe I'm betting off biting the bullet and getting a pair

[adsgreen]

IIRC Audi state something like 3mm difference max

However the front diff is open so in theory you could put what you like on there however it would screw up the stability control.

[IanH755]

I replaced just one (with 2mm difference) but I replaced like for like and I haven't had any issues.

[S4WON]

I replaced just one (with 2mm difference) but I replaced like for like and I haven't had any issues.

Great to hear (and reassuring). Thanks Ian