Proportioning valves are recommended to be installed in the rear brake circuit. The point being that you always want more brake bias in the front brakes - a ratio of about 2 to 1. In a recent post two people mentioned they installed it in the front brake circuit. Their point being with “skinnies” on the front and slicks on the rear they want to decrease front braking. This makes no sense to me since the skinny fronts would have way less grip than the rear.

It would seem to me that if you have to decrease front braking, you don’t have big enough brakes on the rear.

One person commented that “if you chose the right m/c you don’t have to worry about a prop valve”. The fact is: m/c size doesn’t play into this. The m/c will only change the pedal travel and the foot pressure required - the volume of fluid required and sent to the brakes remains the same. Changing m/c’s doesn’t alter the bias.

So can someone please a plain the reason or logic to putting the prop valve in the front brake circuit.