4 pot caliper piston travel

Hi all, simple question, I have 4 pot wilwood calipers with 1.5" pistons at the front, I am wondering how much the pistons will move under braking so I can calculate brake fluid displacement to calculate the smallest MC diameter to start testing with. pedal ratio is 1:5 , I have about halve an inch mc travel.(I don't like too much pedal) I have no booster so don't want to end up with a mc that is too big, thanks ( P.S. total piston area at the front is 14.14 sq.inch)
 

Ron Earp

Admin
Not much at all. They’ll be around 0.050” to 0.075” off the rotor, probably not even that much, and will only travel that distance under braking.
 
Not much at all. They’ll be around 0.050” to 0.075” off the rotor, probably not even that much, and will only travel that distance under braking.
Might want to move that decimal point one more place to the right-like ).0.005'' to 0.0075''.
 

Neil

Supporter
Rick;

Don't try to go too far undersize on your master cylinder. You'll need enough volume to account for thermal expansion, caliper flex, tiny leaks, hose expansion, etc. You don't want to run out of brake pedal!
 
thanks guys, information is much appreciated, can't wait to start on the brakes as it is the last thing to do (was not happy with the esprit front brakes I used before but the car is legally on the road now so I can change them for someting better)
 
looks like a 0.625 MC is already giving enough volume, I have a 0.625 a 0.7 and a 0.75 MC laying around so will start with the smaller one and see how it goes. thank you all.
 

Terry Oxandale

Skinny Man
I use 3/4" on my MCs, but I've got larger pistons (1.75"/1/82") on my calipers. For my needs, it's a great balance between effort and travel.
 
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