Do RS5 rear rotors fit the S4?

[TEB]

I know they are both 330 x 22, but is the offset the same?

I just upgraded my fronts to RS5 and want to get rear rotors to match the fronts (OEM RS5).

[TEB]

I guess the corollary question is whether anyone knows someone who makes these two piece OEM-style rotors for the rear of the S4?

[Smac770]

B8 rear 330x22 is the same architecture for all the B8 products. B8.0 or B8.5, A4 through RS5. The one difference is the change in the EPB servo motor between B8.0 and B8.5.

These are the B8.0 RS rear rotors: 8T0 615 601
https://www.lllparts.co.uk/product/s.../mpn/8t0615601

These are the B8.5 RS rear rotors: 8T0 615 601 A
https://www.fcpeuro.com/products/aud...vag-8t0615601a

B8.0 S4 and B8.0 RS5 use the same calipers.
B8.5 S4 and B8.5 RS5 use the same calipers.
B8.0 S4 and B8.5 S4 use the same rotors.
B8.0 S4/RS5 and B8.5 S4/RS5 all use the same pads.

So seems a pretty safe bet you can just throw the RS rotors on the S or vice versa. You just pick up drilled and wavy. I don't think they are real two piece, just carved up for reduced weight.

[TEB]

Thanks, great info. They are definitely 2-piece as the hat is aluminum and the ring carbon steel. I don't think the rings can be replaced independently, though.

[sepheroth86]

Just a thought.

While the caliper may be the same, is the carrier also the same?

Do the RS cars have a different offset for calipers and brake disc hats?

[blackfunk]

I don't think they're the same because the rear caliper on the RS is very different vs the S models, so I'd say they're different.

[TEB]

Just a thought.

While the caliper may be the same, is the carrier also the same?

Do the RS cars have a different offset for calipers and brake disc hats?

The carriers are the same part numbers between the S4 and RS5.

[Smac770]

In the context of this question:
The only* difference between S and RS is the rotor.
The only* difference between B8.0 and B8.5 is the EPB servomotor.
* B8.5 RS did add a pad wear sensor to the right rear.

[B18b1ex]

You should check to see if the hat offsets are the same. I thought at one time someone suggested having to swap hubs.


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[Smac770]

Ah, I think B18b1ex found the crux.


So all B8 and C7 use the same wheel bearing on all four corners, 4H0 498 625 A.

And all B8 and C7 use the same wheel hub on all four corners, 8K0 407 613 B - https://www.shopdap.com/8k0-407-613-b.html
EXCEPT for the rear on the RS models (RS5, RS7 in US), which use 8K0 407 613 D - https://www.ecstuning.com/b-genuine-...ch/8k0407613d/

(the combined 4H0 498 625 A + 8K0 407 613 B is 8K0 407 607)

So what's with the B hub vs D hub? Notice what appears to be extra thickness in the hub:

B: D:

Here we see the B hub mounted in the bearing:


Here we see the D hub mounted in the bearing:


Notice the extra thickness between the edge of the bearing and the lug bolt protrusions.


If we look at a third-party with rotors for both the A/S and the RS, we see:

A/S: RS:

So the RS 300x22 is 5mm taller than the A/S 300x22. That would allow it to sit on the D hub with it's extra protrusion but get the rotor friction wheel back to where the caliper is. Since the A/S and the RS use the same wheel bearing housing, same caliper carrier, same caliper, and same pads.

We get an excellent diagram from Brembo regarding the A/S 300x22: https://www.bremboparts.com/america/...isc/09-B969-11
But they don't make a rotor to RS specs so no nicely specific diagram of the rotor physicals that I can find.


It would seem then that the A/S 300x22 is used with the B hub, but the RS 300x22 must be used with the D hub.

[timmyzr1]

Same thing, have them at the back waved oem rotors

[blackfunk]

I just realized that I wrote caliper - my intent was to write hub - is very different. I tried switch to RS rotors a few years back and encountered that issue where the RS track I believe is wider, hence the additional 5mm of the hub. From my understanding you needed to change out the hub as was mentioned above.

[TEB]

smac770, this is great information. Appreciate you doing the leg work. I reviewed all the caliper/carrier part numbers between the two, but never thought to check the hub.

[TEB]

Same thing, have them at the back waved oem rotors

You are saying you have RS5 wave rotors on a B8S4? Given the discussion above, did they fit well? I guess it's possible that the floating caliper could have enough lateral movement to cover the 5mm difference in rotor position?

[timmyzr1]

You are saying you have RS5 wave rotors on a B8S4? Given the discussion above, did they fit well? I guess it's possible that the floating caliper could have enough lateral movement to cover the 5mm difference in rotor position?

Yes exactly! I have front RS5 full brakes conversion, and rear oem calipers and RS5 oem waved rotors. ill get some pics today.

[TEB]

I suppose 5mm spacers between the hub and rotor would work.

[drunkentrader]

Ah, I think B18b1ex found the crux.


So all B8 and C7 use the same wheel bearing on all four corners, 4H0 498 625 A.

And all B8 and C7 use the same wheel hub on all four corners, 8K0 407 613 B - https://www.shopdap.com/8k0-407-613-b.html
EXCEPT for the rear on the RS models (RS5, RS7 in US), which use 8K0 407 613 D - https://www.ecstuning.com/b-genuine-...ch/8k0407613d/

(the combined 4H0 498 625 A + 8K0 407 613 B is 8K0 407 607)

So what's with the B hub vs D hub? Notice what appears to be extra thickness in the hub:

B: D:

Here we see the B hub mounted in the bearing:


Here we see the D hub mounted in the bearing:


Notice the extra thickness between the edge of the bearing and the lug bolt protrusions.


If we look at a third-party with rotors for both the A/S and the RS, we see:

A/S: RS:

So the RS 300x22 is 5mm taller than the A/S 300x22. That would allow it to sit on the D hub with it's extra protrusion but get the rotor friction wheel back to where the caliper is. Since the A/S and the RS use the same wheel bearing housing, same caliper carrier, same caliper, and same pads.

We get an excellent diagram from Brembo regarding the A/S 300x22: https://www.bremboparts.com/america/...isc/09-B969-11
But they don't make a rotor to RS specs so no nicely specific diagram of the rotor physicals that I can find.


It would seem then that the A/S 300x22 is used with the B hub, but the RS 300x22 must be used with the D hub.

Just replying here to confirm that RS5 rear hub outter(spindle?) are unique to the RS5 and stick out an extra 4mm or so. The wheel bearings and wheel besrign carrier/assembly are the same front to rear, but the damn rear spindle is RS5 specific. Typing this as my rs5 is sitting on a lift after buying the wrong spindle… oem units back ordered. Was lucky to buy a used on on eBay 30 miles from me…

[B18b1ex]

I suppose 5mm spacers between the hub and rotor would work.

Don’t do this.


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[ThoseRings]

Adding this for anyone searching.


I went down this rabbit hole while looking into the RS5 BBK and it looks like the rear RS5 calipers are the same as what the S4/S5 has with the exception of the "RS" plate.

So that means there is no added benefit of running the RS5 rear caliper unless you want/have a set with the "RS" plate.

For rear rotor upgrades you can go OE S4/S5 which there are many options or even RS4 with no other mods from what I found.


If you want to run the rear RS5 rotor you will need the rear spindle/hub to do it the right way which will widen the track of the car.

[s vier]

I came here to see if my RS5 rears would fit on my new daily 13' S4 and left with the "Sorcerer's Stone" of info I had been looking for to properly put RS6 Performance rear CCBs onto my RS5. Thank you all!