Pedal Force Settings

 Pedal Force Settings

When developing "muscle memory" for precision braking, it is useful to know the forces.

The best way to measure is with a "Force Dyno or Gauge" like this one:

Most high end pedals have software that allows "shaping" of the force curve. Linear is almost always the best.

In iRacing, the calibration can be "fine tuned" by adjusting the settings in the "joyCalib" file. 

- DeviceName: 'GTpro Pedals'

   InstanceGUID: 

   AxisList:

   - Axis: 2

     AxisName: 'Y Axis'

     CalibMin: 10

     CalibCenter: 180

     CalibMax: 325

These are my settings and are unusual in that my damaged and handicapped legs cannot push the maximum much higher than 30 pounds. Normal settings would be well above 75 pounds. (CalibMax in the 500-600 range)

The CalibMin is set to reduce unintended brake application when inadvertently resting left foot on pedal. It creates a "dead zone". 

Use the input graph to train your ankle and leg to recognize and repeat the Min, Medium, and Max levels.  Essentially, my trail braking requires precision force input in the 20-30 pounds force range. 

The chart above shows the forces using an orange and black combination of elastic bushings on the pedal slave cylinder. The chart below (black line) shows figures with two black bushings. Note the lower force (18 vs 20) necessary for the 10%.  In other words, a slightly smaller dead zone. Lower inputs for higher forces as everything is stiffer with slightly less pedal travel. I noticed that moving from the orange black combo to the double black caused me to over brake and over slow too early and I did not trail off properly.  joyCalib could have corrected this but I did not like the firmer pedal. 

Pedal and Foot Geometry

 Pedal and Foot Geometry

Optimization of the angle between your feet and the pedals is critical for the fine inputs necessary to achieve your best lap times. The timing and precision of braking and throttle in corners is the difference between the fast and REALLY fast drivers.

My rig uses Ricmotech GTPro pedals with hydraulic brake master cylinder which then compresses a composite bushing. The pedal travel and effort are infinitely adjustable. Then with the desired configuration/calibration of iRacing software, the pedal effort to reach 100% braking is finalized. My pedal travel for 100% braking is about 3/4 inch with about 35-40 pounds of leg force. (I am handicapped from an aircraft crash where I broke both femurs and my left tibia so the force I can apply to the brakes is limited.  Before the accident, I had the brakes calibrated to reach 100% with 100 pounds of force and about 1" of travel. ) 

My leg is bent at the knee at about 30 degrees to insure I am using my quadricep as well as my calf and ankle muscles at max braking. The other critical angle is at the ankle. I am pressing on the pedal with the ball and big toe of the foot with the ankle 90 degrees to my leg. This allows for fine control of brake force even down to 10% braking or 20 pounds of force.

In order to get the correct geometry, I fabricated a semicircular block to support and position my heel. To insure my foot was always correctly positioned on the pedal, I fabricated a "cuff" for my ankle.  (see Figure above) The cuff was sculpted by carving a yoga block and is attached to the foot plate with HD Industrial Velcro.

The throttle is set to have 2 inches of travel.  To allow for heel/toe shifting, the throttle at "zero" is even with the brake pedal when brakes are applied. So at full throttle the pedal is 2 inches further "away". My heel support for the throttle is forward of the heel support for the brake. My leg is less bent as little force is needed for the throttle and movement is controled with the ankle. At full throttle, the right ankle is at 100 degrees and about 90 degrees at the most critical 50% throttle position. 

Once the geometry is fixed, it will take several hours of practice to sufficiently develop the muscle memory to apply fine pedal inputs accurately and consistently.