hi guys, i'm new to the forum, i own a 54 plate a4 1.8t 163 limited edition. i'm wanting to change my brake discs and pads, and wanted to know what size discs they are, as i have been told there are two sizes?! any help would be much appreciated.

Gaz

 

1.8Ts have 288x25mm front rotors and either 245x10mm or 255x12mm rears. Couldn't tell you which rears you have, but your fronts are 288x25mm. It is possible to put the larger 312x25mm front rotors from the 3.0 V6 cars on your 1.8T if your wheels will clear (16s will for sure, don't know if you've got 15s), but it requires changing the caliper carrier. The caliper itself stays the same, however, so it's a fairly cheap upgrade, as brakes go.

Pretty much everything you need can be found here:

Audi B6 A4 Quattro 1.8T > Braking

I'm sure plenty of the other vendors have options as well - ECS just happens to have a pretty wide selection of both stock and upgraded brake stuff.

 

Yeah, the bummer is that there's no real good way to know which size your rear rotors are without measuring them. All 3.0 cars got the 255x12mm rotors, but with the 1.8 it could be either.

Here's a link on how to determine which size you'll need.