TTRS rotors - would they fit our RS6?

[mik15]

so, been looking lately for rotors as mine seem to be starting getting scored by the pads, came across the TTRS ones which are 370mm in diameter and look as below, wondering if anyone has tried fitting these on our cars....

as far as i can tell they seem to fit...and i think they're also lighter than ours...

vs

[Other_Erik]

I'd think you would get some wobble if they did fit at all.

Factory rotors are 365x34mm IIRC, and stock TTRS rotors are 340x25mm. There are some BBK's out there with 370mm rotors for the TTRS, but they're all fitted tight to a 66.56mm hub, where you'd have ~4.73mm of play on each side of the 57.1mm hub on the RS6.

In short, I wouldn't recommend it. You'd be introducing problems into your build from the start...

O_E

[mik15]

as i found TTRS has the CB similar to ours, 57.1 and the disc diameter is 370mm x 32....i guess the only problem would be the 32mm thickness, at least so far, still don't know if they will physically fit...

the 32mm thickness could mean that the braking surface is thinner or that the vanes are smaller, unless you put it face to face is hard to tell...i drove the TTRS and its brakes do stand very very good when you're really abusing the car, and that particular TTRS was abused since it was a courtesy car for a few days .

On the other side the TT is not as heavy as the C5 RS6, it has almost 300kg less, so yeah, the 32mm thickness might be an issue...

[Other_Erik]

I'd be concerned about the weight difference standing up under spirited driving in the pig-heavy RS6. The greater the mass of the rotor, the more heat it'll be able to absorb, and given the same vane pattern, the greater the amount of heat it'll be able to disperse. Good luck!

O_E

[Other_Erik]

Don't know why this double-posted, sorry 'bout that

[Korben007]

Believe the hat height is different. I can post some pics I have both rotors sitting here!

[4everRS]

Believe the hat height is different. I can post some pics I have both rotors sitting here!

that is pretty convient!

[mik15]

that would be great if you have both in your hands , maybe throw in some quick measurements, it would really help...thanks.

[lswing]

Personally I would never skimp on rotors. Even though they cost a few more bucks, it's a part that has your life on the line, and will actually last for 30-50k, unlike most other things

[Korben007]

Hub height to shallow on the TT rotors. If it was the other way round you could use a spacer.

Though you could use a spacer between the caliper and upright and get the caliper moved outboard a tiny bit. Perhaps I shall experiment

[SteveKen]

Be sure to measure from the center line of the rotor thickness to the back surface of the hat.

I'm assuming that the hat thickness sandwiched between the hub and wheel and rotor thickness might not be the same....

[Korben007]

I get the exact number but a spacer somewhere will make them work if they have radial clearance going from 365mm to 370mm

[Korben007]

did some more measuring with a caliper this time. lots of measurements are the same. The hub thickness the contact width 64mm vs 63mm. Its hard to get a an exact measurement since both my rotors have been machined and are a little thinner then normal. Im gonna test fit the rotors here soon and will report back i imagine only tiny shims will be needed to make them work! And for half the price it would be well worth it!

[mik15]

yeah, that's what i thought, it does worth a try considering that they're $400 a pair compared to almost $1000....which one would you say is lighter? the TTRS one seems to be lighter, picture judging

[Korben007]

The weight difference is minimal. I did some test fitting today and you can make them work. The center bore has to opened up about 3mm to 68mm to fit the rs6 hub. The calipers will need to be spaced out 2.5mm radially. And the bracket to hub forward about 3mm. I did not bore out the center of the rotors because I need these to fit the TT still. I am very confident these can be made to work with minimal effort. Will post pics in a bit. I will be using this option when my stock rotors are done for.

[mik15]

why would you need to bring it to 68mm since they're already at 57.1, just as the CB of the RS6 C5? shouldn't they perfectly fit the hub?

[Korben007]

Cause the rotor sits on a lip that's bigger then the wheel bore. It's 68mm on most audis. For some reason the TT is a little smaller. Not hard to fix though.

[Korben007]

washer makes a perfect 2.5mm spacer.
rotors fits nicely just needs caliper shifted outboard slightly.
inside
outside
Keep in mind that rotor is not fully seated on the hub due to center bore difference. So the exact size spacer you need I'm not sure. To lazy to do the math right now but I know is will be minimal. Like 5mm at the most.