[JohnM 855 T5R]

Another CNGBiFuel rant? I have to say, your knowledge of basic physics is somewhat rudimentary and the argument you put forward is very flawed as you are applying wholly inappropriate elements of the theory of mechanics. For my part, speaking as someone who a) has "A" level physics, b) was in production engineering at Ford for some years and c) rallied for 12 years engineering, building and maintaining my own rally cars I know enough about braking to dispel your notions.

Braking comes down to just three factors -
1) Pad area - obviously this determines how much friction material is in contact with the disc.
2) Friction material - the co-efficient of friction will, in simple terms, determine how well the pad "grips". A high co-efficient however as we all know comes at a price - the pads usually have a narrow optimum operating temperature range and work worse when too cold plus the pressure that needs to be applied to take advantage of high friction material is normally greater which leads to...
3) Clamping pressure (the force that is applied through the pads) - i.e., how hard you shove the pads onto the discs. Apart from the strength of your right foot, the amount of clamping pressure that can be applied is determined by the design of the caliper itself and its hydraulic relationship to the master cylinder (along with the brake booster which makes higher brake pressures possible without having to go to the gym.)

Having a larger 302mm disc and moving the caliper further out with the required mounting brackets put the pad into contact with a part of the disc which has a higher surface rotational speed. This makes absolutely no difference whatsoever in terms of the basic physics of braking. If you use the same pads, calipers, master cylinder and brake booster you will get diddy squat improvement on 302's. As I said, the only benefit is in extreme conditions where fade might be delayed due to the increased ability of a larger chunk of metal to soak up generated heat and the higher rotational speed at the rim of the vented disc to dissipate in the the airflow.

Back to the classroom and get your basic physics right

I like your rants when founded in common sense and fact - and I agree with you a good deal of the time. But sadly, a fact free rant just irritates.

Regards
John