Alright guys, after spending like 1 hour reading all the topics related to proportioning valves i still haven't gotten my question answered.

My question is what is the difference between all of the different proportioning valves?

3030
3040
4040

i'm not talking about drum disc BS i'm talking about which valve splits the Front/Rear Bias differently and what are the percentages.

I don't want Opinions, i want facts! I have experianced all valves and have my opinions but i want fact which does what.

I REPEAT...i don't want no information about 4040 for 4 wheel disc blah blah i want the exact percentage of front/rear bias between the different proportioning valves.

 

You won't get an accurate answer because it's not that simple.

Piston diameter and caliper & disk dimensions controls front-rear bias.

The proportioning valve doesn't do it until the hydraulic pressure exceeds a certain amount. Then above that pressure, it sends proportionally less to the rear brakes. So once you exceed the pressure of the 'knee' in the curve, at higher pressures the proportioning valve reduces rear pressure. Then your front/rear bias is no longer constant.