Active Steering

[davidjpowell]

I have a courtesy car today (a BM 325d) with Active Steering.

It is the most bizarre driving experience. The service manager described it as 'variable geometry'. The amount that you have to turn the steering wheel changes with your speed. So at slow speeds, say a mini roundabout, you can navigate with less than a quarter turn on the wheel. On the motorway that same quarter turn sees a far smaller change of direction.

Total turn lock to lock is 1.9! I'm not sure if mercedes do this as an option - but it is worth a look if they do.

 

[stumpy1]

You do kinda get used to it though it can feel mighty weird at first. The problem I see is when you drive different cars you can forget which options are fitted, like parktronic for example.

 

[Dieselman]

Total turn lock to lock is 1.9! I'm not sure if mercedes do this as an option - but it is worth a look if they do.

Parameter steering is standard on more upmarket E class and S class and optional on lesser models.

I've never driven one but would love to try a Citroen SM with just under 1 turn lock to lock, CX and XM use 1.9 turns for their DIRAVI variable setup so are less Go Kart.

 

[davidjpowell]

You do kinda get used to it though it can feel mighty weird at first. The problem I see is when you drive different cars you can forget which options are fitted, like parktronic for example.

The dealer was carefull to make sure that they warned me about the system. I did look very carefully at the post next to the car!

 

[Mactech]

There are some strange ideas about steering and how it should be. I like, and am used to Mercedes 'Parameter' steering which gets a little heavier as the speed rises. Easy for parking, but 'weighted' at high speed.

I have spent quite some time with power steering systems on race cars which are mostly electronic and so you can 'map' them to do almost whatever you want. Having tried many different things we have always come back to these basic facts:

1. Humans are very adaptive and soon get used to the outcome of their inputs.
2. All racing drivers want the car to feel like there is no power steering, but they do not want to put in excessive effort!

We normally end up with an almost linear relationship of steering wheel torque to the amount of assistance. It is critical that the system allows the road wheel to 'talk' to the driver but the power assistance allows us to run more radical geometry and castor trail. This makes the car on wide tyres less upset by surface variations and ruts.

It is a rare system that isolates us from the bumps, ridges and noise of the road yet lets us read what the car is doing as if running our fingers gently over the tarmac……

 

[stumpy1]

The problem I had when using it was when turning right from a side road onto a main rd. It was easy to use too much lock and drive down the wrong lane.

 

[SportsCoupeRich]

It is a rare system that isolates us from the bumps, ridges and noise of the road yet lets us read what the car is doing as if running our fingers gently over the tarmac……

Just the GT Porsches then!?