Parameter v Direct steering

[eng622]

I understand the difference from the previous post and in reviews of the facelift SLK 350 it is referred to as direct steer. But if you look at the latest MB option list it is still called parameter, so I am now confused as to what is what.

 

[st13phil]

The current (i.e. MY09 onwards) R171 SLK comes as standard with Parameter Steering. This is the normal, speed-sensitive power steering system;

As an option (see page 17 of the Jan 2011 Pricelist, available for download here), you can specify and pay for Option Code 213 which is described as Direct Steering. This is also a speed-sensitive power steering system but with the addition of variable rack ratio.

They are different things - as I explained in the other thread.

 

[eng622]

Thanks Phil,
I must have been looking at an old spec on the MB website (says 2004/10) as the info from your link is different. So I understand that face lift models started spring 2008 but the direct steer was not available until 2009

 

[Diesel Benz]

The current (i.e. MY09 onwards) R171 SLK comes as standard with Parameter Steering. This is the normal, speed-sensitive power steering system;

As an option (see page 17 of the Jan 2011 Pricelist, available for download here), you can specify and pay for Option Code 213 which is described as Direct Steering. This is also a speed-sensitive power steering system but with the addition of variable rack ratio.

They are different things - as I explained in the other thread.

This topic is a bit confusing when no other MB web site that I looked at lists parameter steering being standard for the new R171 except the UK site. Even more confusing when WIS explains this option code as "Speed sensitive power steering" for the new SLK too. Attached the front page only, could not attach the whole document (not much need either).

The MB UK site and st24phil must be right anyway, from EPC one can see that the speed sensitive power steering solenoid is standard for the new R171, not dependent on the option code 213.

The "standard 213 speed sensitive power steering" can have variable steering gear too without it being called direct steering, see the 221 description (had to zip the pdf to make it from 101 kB to less than 100 kB). Unfortunately WIS does not explain the standard steering for the R171, the difference could be as "minor" as the difference in the variability of the steering gear ratio as a function of the front wheel angle (perhaps the standard steering works at a fixed ratio only).

I find it quite confusing when power steering is standard and direct steering uses the same option codes as power steering used to have. Perhaps the engineering department designed "Direct steering" simply as "Parameter steering" or "Speed sensitive power steering" but the marketing department wanted to have an option to sell and the standard (speed sensitive) power steering got a fixed ratio steering gear?

 

[st13phil]

So I understand that face lift models started spring 2008 but the direct steer was not available until 2009

Direct Steering was certainly an option on MY09 cars, but I can't be certain about MY08 - the best way to verify that would be to find a MY08 pricelist (sorry, i don't have one).

 

[AndyMac36]

I have a 2006 R171 SLK250 that doesn't have option 213 - Speed-Sensitive Steering and was wondering if it's just a case of swapping the rack for one that does or are there any other elements needed that would make installing it a complete phaff?