R32 Gtr Calipers With A 30mm Thick Rotor?

[BlitzSSS]

Hey

I have R32 GTR calipers using the stock 32mm rotor. Im investigating using a set of adapters to space these out to accept the larger R33/34 bremo sized rotor which is only 30mm thick whilst still using the R32GTR calipers.

Assuming a few people have done this, is it safe ? im a little hesitant considering the rotor brand new is at the minimum "allowed" thickness and when worn will get down to 2mm overall below minimum recomended thickness.

I'm assuming a few people on here have done this, or know wether its 200% safe even when the rotor and pad are nearly fully worn (not that i will let them get that far but i still want to know that its safe even to this level)

Thanks

Edited November 20, 2007 by BlitzSSS

[Beer Baron]

there is no problem doing it. the 30mm minimum thickness is for that specific rotor. the 33 brembo rotors have a minimum thickness of 28mm.

[daisu]

I don't see the point in using a larger diameter disc if the caliper/pad size is the same. Especially since you will be loosing 2mm thickness, I would be sticking with the thicker rotors you have now.

[BlitzSSS]

there is no problem doing it. the 30mm minimum thickness is for that specific rotor. the 33 brembo rotors have a minimum thickness of 28mm.

I'm not worried about the rotors being unsafe, it's the calipers that have been designed to be used on a minimum thickness of 30mm, even though 28mm is only 1mm less per side im still concerned that the pistons won't go past their maximum allowed point and potentially pop out past the seals.

I don't see the point in using a larger diameter disc if the caliper/pad size is the same. Especially since you will be loosing 2mm thickness, I would be sticking with the thicker rotors you have now.

It's still going to provide more braking power, and there is a heck of alot more "metal" in the larger sized rotor than one with an extra 2mm thickness so heat absorption and dissipation will be much greater also. I'd love to buy a set of Brembo calipers but they sell for way to much.

Can anyone else using this combo please advise ?

[Beer Baron]

like I said there is no problem doing it. with calipers, rotors, pistons, seals, pads anything. if you are really concerned about it put some 1mm thick shims behind your pads (which is a good idea anyway).

as for larger rotor not being worthwhile. it's very worthwhile. the caliper now has more leverage as it's operating further out from the centre. also larger rotor means larger capacity to dissipate heat across it's surface. all good things.

[VHR32]

I have fitted R32 / R33 GTSt calipers to Commodores as a conversion and use 28mm discs and never had a problem.

The pistons have to come out a long way before they go past the seal.

the minimum thickness of a disc is more to do with the disc rotor strength (being too thin) rather than worrying about being too thin for your caliper.

Ive seen Landcruiser brakes worn so much they have worn past the flat disc surface and into the ventilated fins by about 7mm and the piston is still working ok!

Really, it is no different running R32 GTR brakes without and shims behind the pads (1mm each side?) like so many do.

Edited November 21, 2007 by VHR32

[BlitzSSS]

Thanks for the replies

[Ronin 09]

I don't see the point in using a larger diameter disc if the caliper/pad size is the same. Especially since you will be loosing 2mm thickness, I would be sticking with the thicker rotors you have now.

at least 3 good reasons

1. increased leverage ratio (higher torque capacity on a larger diameter rotor)

2. increased rotor mass (better heat capacity = less fade)

3. reduced pad and brake fluid temperatures

have a read of some brake threads on here, there is a lot of good info.

think about it this way - why does a brake upgrade kit try and squeeze the biggest rotor it can onto a car?