I am developing an alternative 99 spec rear brake kit. The 99 spec rear brake uses a larger diameter brake rotor (12.36" vs. the stock 11.57" ) with the same 0.79" thickness but the caliper itself is the same spec as the one we have on the US spec RX-7. So why spend $440 on a pair of 99 spec calipers when it has the same dimension of piston and everything else except it sits further out to accomodate the larger brake rotor? If you have seen the group buy on the rx7 forum, the whole 99 spec rear kit costs about $850.



The alternative 99 spec rear brake kit is going to come with the CNC machined aluminum extension bracket to relocate the caliper to accomodate the larger 99 spec rear brake rotor, OEM Mazda 99 spec rear brake rotors and all the misc. hardwares. Target price is $550 but group buy is always possible if there is enough interest.



This kit will perform as well as the 99 spec rear brake as long as your calipers and brake pads are in good condition. The prototype will be finished in about 2 weeks and I will post some photos then. Thank you.



Chuck Huang

im interested........... as always

interested ...

hell yaw

Will this require the use of 17in wheels?

also interested

I will test it out with 16" stock rims. I know the 99 spec front caliper requires the 17" rims. I think the rear one should be ok since the caliper is smaller. But I will test it out with 16" stock rims after it's done.



Chuck Huang

only the rotor is going to be larger right? how about the brake pad, i dnot see how it can be more effective if the same size pad is used.



if im wrong, please correct me, cuz im always interested in learning

Only the brake rotor is larger on the 99 spec rear kit. The caliper itself has the same construction except it sits further out to accomodate a larger brake rotor.



A larger brake rotor will perform better even with the same caliper for the following reasons:



1. More surface area.



2. More material to dissipate heat



As you know, brake system works by turning kinetic energy into heat. Brake starts to fade when the brake rotor does not dissipate heat fast enough. A larger brake rotor with more material and surface area will dissipate heat better so they are less likely to fade under extreme condition.



Chuck Huang

thanks chuck for clearing that up.........



still interested