Brake Bias - Wide "A" with M rears?

[jamesjedi]

I have searched for a while.

I have the wide "A" calipers in the front, and the original "M" calipers in the rear.

What would the bias be for this setup? Would it be ideal? It would be on a car that does not have the rear brake proportioning valve (not sure what to call it?). It is a 77 911S.

Thanks for the help.

[jamesjedi]

I think I have found an answer. I hope Bill V does not mid my quoting him.

A small brake upgrade for SC or earlier Carrera is to use the wide A caliper and rotor w/ stock rear M caliper and rotor. This retains the excellent 9 bias seen in all 911s through '83.

Similarly '84 can leave their front alone and change the rear to the regular M rear using the regular M 20mm rear rotor instead of the wider 3.2 Carrera 24mm rear rotor and wide M. This gives the car excellent bias once the stock p/v is removed.

[Bill Verburg]

Bias is the same 1.491 w/ M front, A, S, or wide A in front and M in back

the only combination that gives poor bias is when the rears are wide rear M. Any of the above fronts w/ wide A rear is 1.220, a p/v raise that to a more acceptable but too much front ~2.26

[jamesjedi]

Thanks Bill!

[moneymanager]

Just leave it alone. Setup works perfectly, or has for forty track events.