proportioning valve setting? help please

I set my prop valve by taking my car out on either a dirt road or right after a rain. Do several hard stops from around 30 mph. You should be able to tell if the fronts or rears lock up first - adjust your prop valve accordingly. Once you get the brake bias dialed in, back out the rears just a little. Ideally you want the fronts to lock up first in the event of a panic stop.

Tim

65 fastback said:

I set my prop valve by taking my car out on either a dirt road or right after a rain. Do several hard stops from around 30 mph. You should be able to tell if the fronts or rears lock up first - adjust your prop valve accordingly. Once you get the brake bias dialed in, back out the rears just a little. Ideally you want the fronts to lock up first in the event of a panic stop.

Tim

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What he said, but I think you should be doing it on dry pavement, and a little slower (maybe 15-20mph). On dry pavement, you can be pretty sure that the front and rear wheels have similar friction with the pavement, while that may or may not be true on a dirt road or in the rain. Go slow, and be careful. Best bet is to have a friend (outside the car) tell you which wheels lock up first. It's possible to do it yourself (ask me how I know), but I'm not sure it's wise.

Do a hard stop, note which wheels lock, and adjust your prop valve. Adjust it until the front wheels lock just a fraction of a second before the rear wheels. It'll take a few tries to get it right - be patient.