Prodrive - Vehicle dynamics that actively toe the line

Prodrive, is developing a vehicle dynamics system that actively adjusts toe angle to improve vehicle handling. Known as Active Toe Control, it works on the rear axle of front wheel drive cars to optimise the toe angle, depending on the speed of the vehicle.

This helps overcome the static toe compromise of either giving a vehicle agile handling at lower speeds or making it more stable and predictable at high speed. Advances in tyre technology and suspension, mean that the dynamic capability of modern cars is now so good, that it is rare for drivers to ever reach a vehicle’s limits.

To give a vehicle additional low speed agility, the wheels usually have up to a degree of toe‑out at the rear axle, while to make a car more stable at higher speeds, for emergency manoeuvres like a lane change, then toe-in is preferred. This makes any fixed toe setting a compromise and one that has contributed to the increasing use of complex multi-link rear suspensions in mid-size hatchbacks; a design previously reserved for high end vehicles. However, while they work extremely well, such rear axles are far more expensive than the traditional twist beams they replace.

Active Toe Control, fitted to an existing twist beam axle, can give many of the dynamic benefits of a multi-link system, but at less than half the cost. Cars with this tight lateral acceleration and yaw rate phasing tend to turn in well and it is a typical set up for competition cars.

Prodrive has identified a preferred mechanism design to adjust the toe angle and is looking for a hardware partner to take the project to a working prototype.