Active Front Steering (AFS): Notes

The Active Front Steering (AFS) system varies the steering gear ratio from direct to indirect and vice versa as a function of the vehicle's speed. Active Steering offers the following advantages:

• Direct steering (reduced gear ratio) with no more than minimal movements of the steering wheel at the low end of the speed range.
• More indirect steering (increased gear ratio) at higher speeds in conjunction with enhanced driving stability.

It would not be possible to provide the benefits offered by AFS with a conventional steering system, as there would inevitably be a need to compromise:

• Steering cannot be too direct as otherwise it would be overly sensitive when the vehicle is travelling at high speed, however direct steering is significantly more desirable for low speeds or when parking.

With AFS there is no need to compromise since the steering directness varies with speed, which results in three major benefits/enhancements:

• Agility
• Comfort
• Safety

With the introduction of the E90, Active Front Steering (AFS) becomes available as an option for the 3 Series.