2.8RSR brake discs - sizes front & rear?

[patrick911]

I can't find anywhere what discs the 2.8 RSR was fitted with in 1973.
All books & articles provide info on the calipers but not on the discs. The RS had ventilated discs, but the RSRs look larger and they were cross-drilled as can be seen in period pictures.
They also differed from the standard discs in that they were floating, as they had lightweight bell hats.
EB-Motorsport sells discs that they say are for the RSR and they are 300 X 32 front and 300 x 28 rear. Can anyone confirm that is correct?

thanks,
Patrick

[gled49]

Yes that is correct. Front rotors are basically 78-79 Turbo and rears are the same but 28mm (1 1/10”). Rear lug drive rotors are impossible to get, so they have to be made. I have a new single rear rotor, I’ve hade for years.

[patrick911]

thanks for confirming.
I purchased the front & rear rotors for the 78-79 turbo and indeed, the fronts (930.351.047.00, 304 x 32) fit with the front disc bells I got with the Zuffenhaus brakes,
but the rear discs have the metal bell-hat fixed so that doesn't work with the light-weight bell hats I have.
The rear 'floating' rotors are hard to find.... and expensive; It's a lot of $$ for a 2kg weight saving for both discs.

[uai]

https://historicdb.fia.com/ Should have brake dimensions for any car used in competition

[gled49]

U can also cheat and run front rotors on the rear ALU hats. U will have to come up with alternative E brake.
Not a good shot but bottom shelf, I run front rotors on the rear.

[patrick911]

thanks again, I already purchased the RSR e-brake system so will probably have to find an alternative, but I did try to 'dry-fit' the front rotors with the rear hats.
Got the hats from TwinSpark Racing (suspect they're the same as EB-motorsport). Beautifully made. It's like with the calipers, almost a waste you hardly see them when fitted.
top of picture is the front rotor with rear hat, below is the standard rear turbo rotor (930.352.045.00).

[dwa911]

Try the guys at Differs (ex TwinSpark) they sorted it out for my 2.8 RSR build. They'll have the info you need.
Joost or Leon - https://www.differsgroup.nl/en/