NB8B Rotors service minimum thickness

Magpie · Postby **Magpie** » Thu Jan 16, 2014 4:18 pm

Can somebody confirm the specified minimum thickness for the OEM front (270mm) and rear (275mm) NB8B rotors?

I have been told 20mm for the OEM front.

I'm thinking of trying out some different pads and have these rotors sitting at home. Plan is if they are still serviceable, have them machined and then fit some different pads and test at QR next Wednesday night. These rotors and pads will be used for track only so changed as required. The changing of the rotors will also be the trigger for giving the car a once over.

Thanks in advance.

manga_blue · Postby **manga_blue** » Thu Jan 16, 2014 4:30 pm

OEM rotors are 20mm front, 8mm rear minimum. Aftermarkets are usually the same but in any case the minimum should be stamped on them somewhere.

Thin rotors warp and overheat more easily than thick ones, so going down to the factory spec minimum is not a good idea for track rotors.

Magpie · Postby **Magpie** » Thu Jan 16, 2014 4:39 pm

manga_blue wrote:OEM rotors are 20mm front, 8mm rear minimum. Aftermarkets are usually the same but in any case the minimum should be stamped on them somewhere.

Thin rotors warp and overheat more easily than thick ones, so going down to the factory spec minimum is not a good idea for track rotors.

Thanks, I will measure them and see what they are when I get home. It will not be worth machining them it they are just on the service limits.

Just got an email from Jason at MX5 Plus:
When measuring for machining, we allow an extra 0.8mm. So the fronts need to be 20.8 and the rears 10.8 otherwise its not worth machining, as you need to allow enough to remove material, and enough to allow for the next amount of wear

Magpie · Postby **Magpie** » Thu Jan 16, 2014 9:09 pm

Well good news the fronts are 21.57 mm each and the rears are 9.58 and 9.52 mm. The disks have what is the minimum thickness cast into the inside of the rotors and for the fronts it is 20mm and the rear is 8mm so I have more than enough.

Now I just have to decide on pads. QFM A1RM are in stock and I can pick them up tomorrow, however also looking at the Hawk blue (front) and HPS Plus (rear) as well as XP12 (front) and XP10 (rear). It could just depend what I can get by Saturday or I hold off. The plan is to get the pads/rotors bedded in before the night sprints on 22/01/14 at QR. Painful that I now have to work Mon to Fri

manga_blue · Postby **manga_blue** » Thu Jan 16, 2014 10:45 pm

You're Queenslander aren't you? Do you really have a choice?

Actually I just punted the ute down a very long very steep mountain descent with a bit of a load on the back. No fade, no fluid boiling, no disc warping - just good consistent braking. That's never happened before on that road. First time I've done it with new QFM HPX pads. I'm very impressed.