Brake caliper piston counts

[jaik]

I'm looking to learn a bit more about brakes. I know the very basics of how they work but got to wondering today about the advantages/disadvantages of having higher piston counts in the calipers and why. Is it to increase the possible pad area? Is it to do with multiplying hydraulic force? Is it a heat issue? I have no idea.

Anything good to read on the topic would be appreciated as much as an explanation

[GreenV8S]

I don't know, but my guess is to distribute the force over the pad and avoid the backplate flexing. The bigger the pad the more tendency there will be for the backplate to flex under hard braking which causes an uneven pressure distribution over the pad and makes the brakes feel horrible.

[oakdale]

Although the pad area effects its wear rate and its ability to dissipate heat, it is the mean radius that the pad acts upon the disc that governs it's braking effort (for any specific coefficiency of friction).
Multiple pistons allow a narrower long pad (to give the required area) which acts on the disc at a bigger radius thus allowing greater brake effort for a specific area of pad and disc/wheel size used.

Edited by oakdale on Wednesday 19th November 14:49

[jaik]

oakdale said:

Although the pad area effects it's wear rate and it's ability to dissipate heat, it is the mean radius that the pad acts upon the disc that governs it's braking effort (for any specific coefficiency of friction).
Multiple pistons allow a narrower long pad (to give the required area) which acts on the disc at a bigger radius thus allowing greater brake effort for a specific area of pad and disc/wheel size used.

Excellent, thank you