Brake Lock Differentials

Brake Lock Differentials (BLDs) are part of the ESP® base algorithm and tuned for on-road activity. Brake Lock differentials improve vehicle mobility by applying braking force to a driven wheel that is spinning faster than the mate on the same axle to provide an equal amount of torque for each wheel, thereby providing torque to the wheel with the most traction. The on-road BLD is calibrated for on-road conditions such as when one wheel is on ice or gravel and the other is on dry pavement, this type of condition is called a split-friction surface.

Vehicles equipped with the Off-Road Group (sales code AWL) include a separate set of BLD calibrations that are designed for Off-Road mode use while crawling over obstacles, during heavy articulation activity, split-friction surfaces and other conditions. Off-Road BLDs direct torque from the wheel that slips to the wheel with more grip on a given axle helping maintain forward mobility over all types of off-road terrain.

Off-Road BLD calibrations are activated when the vehicle is in the Off-Road mode. The Off-road calibration applies much more aggressive and longer duration brake caliper clamping than the calibration for on-road BLDs to achieve the desired performance over off-road events.