OK, well it's new to me, but also somewhat new to the Mini. I spent the weekend installing a TCE Big Brake Kit via Randy Webb. This kit featurs the new larger rear rotor. I'll start by just posting a before and after pic of the rear wheel. I have some othet instalation pics I will post shortly.

AFTER . . . . . . BEFORE

 

Wow, that rear rotor is a lot bigger. Looks much better! :smile:

 

Looks great! You never think how small the OEM rears are until you see a comparison like that!!


p.s. Thanks again for your help....it's installed, and off to the dealer in about an hour...

 

Look like the brake pads only grip 50% of the discs?

 

The BBK is limited by the stock caliper.
I think I see aftermarket brake pads installed- that helps.
The stock rotor is using a much smaller diameter while the TCE rotor uses a much larger diameter- I'd expect that the surface area of the rotor in contact with the brake pad would be similar to slightly larger than stock.

Another consideration is that the total mass of the rear rotor is much much larger and can handle heat loads much better than the stock rotor- this means the brakes perform better and resist overheating better.

The rotor slots also help remove the boundary gases compared to stock.

 

Same pad as before, so perhaps 50% might be a way to look at.

Rotor torque value is up about 15%.