8 replies to this topic

[human89]

I am really confused why someone would want to go to a smaller brake caliper. Is it just to get smaller wheels or are they better brakes.

[mister bridger]

Yes, you won't get 10" wheels over 8.4" discs

[human89]

So just a smaller wheel. But wouldnt the 8.4 offer more stopping power?

[Ethel]

Mainly for the smaller wheel. There isn't much difference in the brake performance, the piston sizes and pad area are very similar. If you look at photos of the 2 discs you'l see how the 7.5 gives more disc diameter over the more conventional 8.4 by how the mounting flange is designed.

 

The 8.4 does give the pads better leverage against rotation, but the 7.5's were designed for use with a servo.

[human89]

I have a servo on mine but i have 12 inch wheels. Im curious if i have 7.5 calipers now. Maybe a previous owner changed the wheels. How can i tell if i have 7.5 or 8.4

[nicklouse]

just look they are very different. or Measure.

[Ethel]

Pad retaining pins go through holes in the pads on 7.5's.

[Spider]

Also, the drive flanges mount differently. The 7.5" have 4 x Phillips head screws and the 8.4" have 4 x hex head bolts.

[Cooperman]

To consider the stopping power it should be remembered that all those race and rally victories on which the legend of our little cars is based were achieved using 7.5" discs and 10" wheels with very few exceptions. 

The pad specification is important and the best Mini brakes I have ever experienced are the 7.5" 'S' discs with Carbon-Metallic pads and AP600 brake fluid running with the standard 'S' servo.