7. Rear binding heel lift.
The lift of the rear heel serves two purposes: The first is to balance the leverage ratios from toe to heel side of the board, and the second is to account for the fact that one foot is behind the other and yet both boots start with the same amount of forward lean. Without heel lift, the rear boot would be over-flexed, and the ankle of the rear foot would be near to the limit of dorsiflexion. Further flexion of the knee in this situation would jam the shin into the tongue of the boot, grind the heel against the back of the heel pocket, and/or kink the board. The distal end of the tibia can also crash into the proximal end of the (Talus), leading to bone spurs and other problems. Some folks can ‘ride’ with both feet flat. I’m sure that someone out there can eat a 60watt light bulb. I don’t care to do either.
The standard 3 degree rear disc is a good place to start if you ride commercially available hard-boots. (Due to the lower internal ramp and stiffer shell of my ski boots, I use a six-degree disc and set my heel lift to 4.1 degrees.) Since heel lift also effects pressure distribution under the foot, it is not advisable to use too much. If too much heel lift is used, it may be difficult to finish a heel-side turn without skidding or sitting excessively towards the rear foot. Too much heel lift will then create fatigue in the front quad, as that leg must bend more to move the hips further back over the rear foot. Excessive heel lift can also delay toeside turn entry by complicating heelside turn exit.