Overview
Balanced brake bias, just like neutral handling, is critical to both safety and reduced lap times. A car which is heavily front biased will be slow and frustrating, but relatively easy and benign to drive. On the other hand, like oversteer, a car which is severely rear biased will be a scary, twitchy ride resulting in a bad case of the white-knuckle syndrome. Envision an imaginary co-pilot yanking up on the park brake handle in the middle of every corner, and you begin to get the idea. Great article here.
For those who don't understand what this is about, brake bias refers to the relative amount of braking force sent to the front vs the rear of the car. A car with ideal brake bias will generally brake in a consistent manner, while getting the most from the brakes. This is tricky to do, and most OEMs now use electronics to accomplish this in a dynamic way.
The pedals that come with the kit have two ways to adjust brake bias: the default is an adjustable bar that divides force between the two brake masters; the other is an add-on assembly that replaces the standard manually adjustable bar at the pedals with one that is controlled by a knob located near the driver.
For street cars, if you are using the standard adjustable rod at the pedals to adjust bias, the beginning approach for these pedals is to set the adjuster bar in the middle. Then you can experiment with changes as you drive the car.
The main advantage to the remote adjustable system is that you can adjust bias while driving, so, if for example, track conditions change mid-race, you can adjust the bias while driving. As you would expect, that easy adjustability is also the main disadvantage- for example, that a correctly set bias will get changed, either inadvertently (as by a kid at a car show) or by an inexperienced driver on track.
One builder has recounted how he installed a remote adjuster in the section below.
One last caveat- the adjusters are not meant to compensate for an incorrect selection of master cylinder sizes. If you have the bias dialed all the way in or out and still don't have good balance, you have the wrong masters- consult the factory or use Fred Puhn's classic book on braking systems to get to the correct sizes for your car.
Tilton Brake Bias Using The Remote Adjuster
Along with great pedals, brake parts, clutches and so forth, Tilton also makes a remote adjuster to manage brake bias in real time. This is a great application for a race or track car that needs to adjust bias due to changing conditions.
The picture series and text below shows the Tilton billet remote bias adjuster mounted to a custom bracket, and shows the entire installation process in an SL-C.
The decal gets applied next. "R" on the right side and "F" on the left:
The picture below shows where the other end of the cable mounts to on the pedal assembly. My finger is pointing to where it attaches with a set screw on the right end of the threaded rod.
The picture below shows the position of the balance point that you want to start with. My finger is showing that I have the balance point directly in the middle. This would be for a 50/50 brake bias. I took measurements with a thin ruler.
To adjust the balance point you simply spin the threaded rod. Looking at the threaded rod from the right side. Clockwise moves the balance to the left. Counter clockwise moves the balance to the right. My left master cylinder is for rear braking and the right one is for front braking.
In the picture below you can see that I'm pointing to the left side of the balance point. My larger master cylinder (7/8") is in the middle position. This master cylinder feeds the rear brakes. Having the balance point moved to the left will now give you more bias to the rear brakes. Adjusting the remote wheel in a clockwise motion will adjust the threaded rod so that the balance point will be favoring the rear brakes.
In the picture below I'm pointing to the right side. My front brakes are hooked up to this master cylinder (3/4"). Moving the balance point to this side will now favor the front brakes.
Start with 50/50 and go from there. Perhaps some SL-C owners can report what they have found as the ideal balance for their cars. Anyone??? The picture shows the jam nut that gets removed if you are using the remote bias adjuster. If not using the remote wheel than you simply thread the jam nut on (without turning the threaded rod mind you) all the way till it jams up against the barrel nut.
The chart included with the billet wheel mentions that every 360 degree spin of the wheel (or threaded rod) moves the bias just under 2 degrees. So if you want a 55/45 rear brake bias you would start at the middle balance position and then spin the wheel approx. 2 1/2 times clockwise. This will move the balance point to the left of center slightly.
In a separate chart it also mentions that every 1/8" inch of pivot movement equals 5 degrees of bias adjustment. So spinning the wheel or threaded rod approximately 2 1/2 times will move the pivot point 1/8" or 5 degrees.
If you want to be "dead nuts" accurate with your starting position of 50/50 then use a small ruler as in the following two pictures. Adjust the threaded rod till both measurements are equal.
To help prevent the remote wheel from being adjusted without your knowing (say for example some youngster sits in your car at a car show and starts spinning the wheel for fun) I plan to install the jam nut on the left side of the threaded rod as in this picture for extra insurance once I have it set up correctly. You could remove the jam nut if you plan to track the car then reinstall for street driving. My finger is pointing to the jam nut.
The brass fittings in the brake residual valves can be removed without damage with some heat from a heat gun as shown in the picture. Do not try to remove them without first applying heat.