Thursday, 27 September 2007

A blast from the past

Going through the day’s press releases (it is a tough, dirty job but someone has to do it) I saw a name that I hadn’t heard in years. The name was ZF-Nivomat which is a self-levelling suspension strut which works using the movement of the suspension to maintain a constant ride height. I first heard about it in connection with early Porsche 911s (where it was the Boge Nivomat) but I suspect the first use was either on the Range Rover or the Ferrari 365GT 2+2.

The advantages of self-levelling suspension include more consistent handling and ride because the suspension is not bouncing along on the bump-stops. Tyres sit properly on the road, which helps road holding and reduces the danger of uneven tyre wear. Even a slight change in a vehicle’s angle of attack can upset the aerodynamic performance of the body; i.e. a heavy load in the back forces the back of the car down and the front up, increasing aerodynamic drag. Even the headlamps work more effectively because their aim is not upset.

ZF were keen to stress the advantage of a self-contained unit in terms of simplicity and economy. In my experience pneumatic suspension and Citroën-style oleo-pneumatic suspension offer advantages that the Nivomat strut cannot match. What cannot be done is to easily incorporate pneumatic suspension into vehicles not designed for it.

1 comment:

David Wilkins said...

I think Boge Nivomat was on the original 3500 SD1 as well but may have been dropped from the more basic SD1 variants that came along later such as the 2300 2000.

Self-leveling is a great feature but can sometimes leave a car feeling a bit slow because it doesn't squat at the rear under acceleration or dive so much under braking.