[urq] Re: B5 S4 vs A8 Rotors

[DasWolfen at aol.com]

 Read at your own risk...Author makes no claim that information is 
complete...

 Here goes....Basically it appears Audi only uses two hub offsets on the 
front. urQ, 4k, Coupe GT 10v Type 44, 80/90, C4 100/A6, C5 A6, B5 A/S4, A8 (not 
S8) and TT...all these cars use a rotor with a total height of about 47mm

 V8/urS/200q20v (w/CORRECT G60 conversion)/S8 all use a larger offset. Not 
sure what it is exactly but its gotta be pretty close to 57mm from my 
observations.

 Not sure what the RS6 uses but I'd guess the larger offset just from caliper 
clearance issues for those HUGE rotors.

 312x25mm A8 and TT....different bolt pattern obviously but rotors are 
otherwise identical. Short ht (47mm)

 321x30mm S4 and A6 4.2/2.7tt, short ht

 323x30mm S8, tall ht

 314x30mm Euro urS6 and IIRC early euro A8's, tall ht.

 288x25mm some A4, 2.8 and I "think" 3.0 A6, C4 100/A6, short ht

 276x25mm Some A4 (any A4 with 15" wheels has this rotor from what I've 
observed), short ht...this is NOT the same rotor as the G60 276x25 used on earlier 
cars although it could be pressed into service in place of the normal G60 
rotor in a pinch.

 All the 25mm rotors listed use a variation of the ATE "57" single piston 
caliper. All ATE 57's (calipers not carriers) are interchangable from year to 
year and model to model 

 Audi also only uses two mounting patterns for caliper carriers....

 Basically anything with a 30mm rotor from the factory will use the wide 
pattern, anything with a 25mm rotor will use the narrow G60 style 
pattern...exception to the rule....ALL A8 and possibly C5 A6 use the wide pattern regardless 
of rotor width.

 How this effects the urQ specifically.....if a specific combo fits a 10v 
Type 44, B5 A4/S4, C4 100/A6, or TT it will fit an urQ as a direct bolt-on 
swap...(remembering that the TT uses a different bolt pattern.)

 Certain other combinations are possibilities....for example...ECS's 314x30mm 
Big Red setup for urS cars will bolt on a urQ (or any other early short hub 5 
bolt car's) with a 321x30mm B5 S4 rotor by simply inserting a suitable shim 
between the caliper and caliper mounting bracket. Anything that fits a TT is a 
direct swap as long as you deal with the bolt pattern issue. 

Confused yet? =0)

Keith