Tyres on a S3... is it true that if one or two of them are worn then you need to change all 4? (been told it messes with the Limited Slip Differential if various wheels have different treads????)
The above question can potentially answer my second question, does this also mean you can not buy good part worn tyres for the s3?
I can't see that being true, tyre come out of the mould with 7 to 8mm of tread and the legal limit is 1.6mm so you can have a maximum difference of 6.4mm in the overall diameter of the wheels. 6.4mm is bugger all really and I could never see how nor have ever heard of it messing about with a lsd.
i think aslong as you change the tyres on the same axle youve not got a problem to do 2 at a time
LSD on an S3...........sounds like whoever told you that was on it! (LSD I mean!!)
This is an old chestnut from the calibra 4x4 days.
Dont worry about knackering anything with worn tyres on different axles. Always best to keep tyres as uniform as possible on a car, just cos it drives nicer, but it wont damage anythign if you have new on the front old on the back etc.
The S3 doesn't have a limited slip diff. It has a Haldex diff between front and rear, which is an electronically controlled hydraulic clutch and varies the amount of drive to the rear wheels. The Haldex IS tolerant of different tread depths, so you can replace rears and fronts at different times.
Originally Posted by Tekin
The other audi's like A4 and A6 etc have a Torsen diff which is fixed 4wd (I think 50:50) unlike the Haldex unit, and these have a very limited tolerance for tread differences, you'll cook the diff on one of those if you have more than about 3mm difference front to rear. This is where the advice has probably come from.
It's probably best practice to have the same tread pattern and depth on each axle though otherwise it'll handle like a pig, ie. replace both fronts or both rears at the same time.
Personally I wouldn't use second hand tyres as they're the only thing between you and the road and I choose life, but if you know they come from a known source then that's different.
Hope this helps.