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-   -   Track day FC... Hawk blue in front. Rear is...? (https://www.rx7club.com/race-car-tech-103/track-day-fc-hawk-blue-front-rear-832695/)

Gene 04-13-09 09:11 AM

Track day FC... Hawk blue in front. Rear is...?
Should I use the blues in the rear as well or should I run the blacks in the rear to shift the bias forwards a bit?

wrankin 04-13-09 11:10 AM

I take it you don't have a bias adjuster? I run the blue/black combo on my FC and I think that I still have a little too much brake in back. I have heard of some folks who run something like an HP+ pad in the rear to get the right bias.

I would not run blues in the rear unless you can control the bias.


TrentO 04-14-09 08:58 AM

I'd agree. I've run the hawk blue/black and still needed a bias adjuster. Same with carbotech xp12 up front and xp8 out back. On my 1st gen I used to run hawk blues up front and pbr metal masters out back without a bias adjuster and it was just about perfect.


dj55b 05-01-09 03:19 AM

are you guys trying to get the car to stay flatter? or be more front biased? I'm kinda new to the whole braking game. What should be the optimal target?

TrentO 05-01-09 09:42 AM

you want as much rear brake as you can until the rear end starts hopping under threshold braking. That way you are getting 100% of the braking force the car can generate. If you have too little rear the front brakes have to do all the work and can become overheated. As well, too little rear brake make the car a little odd under trail braking a you have to let off a lot to keep the front wheels turning. Too much rear and the back starts to hop or just locks up and tries to pass the front.

my $0.02

dj55b 05-01-09 12:18 PM

interesting ... i always thought it would be more front biased. But that makes more sense and like this I don't have to worry about the front end diving too much under hard breaking and rubbing on my tires. I have a first gen that I track (time attack) with second gen T2 brakes all around , and currently have HP+ front and rear and its definatly more front biased. Any recommendations for me on pads configuration?

wrankin 05-01-09 12:22 PM

Trent is right. Also realize that the "optimum" point changes depending on track conditions and other things. That is why you have an adjustable bias valve or bar.

Remember, the bottom line is that you don't want the rears to lock up before the fronts. But at the same time you want the rears to do as much braking as possible.

In the dry with good sticky tires you will be braking really hard, loading up the front tires and lightening the rears. You need more braking pressure on the fronts than the rears since the fronts now have all this nice weight (and traction) on them while the rears are getting less.

With less sticky tires you won't be braking as hard and thus you don't get as much weight transfer and won't need quite as much bias. In the wet even less.

Also note, although it is not obvious, the amount of weight transfer you get to the front tires under braking (or acceleration) is independent of suspension dive. You will get approximately the same amount of transfer on a softly sprung car as you would on a stiffly sprung car, assuming that you can still threshold brake with either (ie. your suspension isn't bouncing off the bump-stops).


Gene 05-01-09 01:29 PM

So the blue-black combo produced pretty good braking. However, while experimenting with taking my braking deeper into the brake zone I managed to lock the rears and do a quarter-spin. I wasn't even going that fast when it happened. I've had trouble with this in the past with different pads too :/

I think an adjustable prop valve may be in my future.

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