Hi all,

W221, S550 2007 pre facelift model. 150,000kms. Sports package.
Suspension feels a bit stiff. I investigated and received conflicting answers. Some say that there is nothing that can be done (other than chaning rims to 18" from 19" and softer tires), while others claim that Airmatic can, and indeed should, be calibrated as over time suspension becomes stiffer. No detectable air leaks, no other issues with the car. So the question - does calibration change suspension stiffness, or is it a hype? Chaning modes from Comfort to Sport does impact transmission (shifts at higher rpm) but not ride quality, or at least I cannot tell the difference. Thanks

 

Suspension does not become stiff because of air suspension issues. Suspension would become harder if the air spring volume was made smaller. The only thing doing that could be water collecting into the spring (assuming car height is kept standard). Never heard of that happen. Cars like the W211 had dual volume air springs (controlled dynamically by a valve), the W221 does not. Note that the air pressure in the air springs does not change significantly even if the car is raised, the springs are just filled with more air. Air pressure is defined by the weight of the car and the cross-sectional area of the air spring and both are quite independent of the car height.

Suspension becoming stiff should be from the shocks that anyway mainly define the suspension stiffness. The car does have adjustable shocks, valves within the shocks are electrically controlled. The new owner of my past W221 was complaining suspension stiffness at some point. I did not feel any difference myself and the valves seemed to operate fine (solenoids worked fine, impossible to say if the actual hydraulic valve moved correctly).

 

the roads are becoming truly disgusting in the UK - now and then I find a bit of road that almost meets that description and its a very different car

tyre brands and tyre pressures, make a huge difference, as does the C or S button - one is a disgusting mess and the other wallows a bit, in trade of for 200% reduction in crashing over bumps and jumping about the road

after 5 years I moved from my original 17" wheels to the OEM 18" option (at the time) it has taken the car from having ride comfort and some grip and control - to behaving like a wayward tank with a miss fire on a cobbled street

 

Thanks for you replies!

 

actually I did remember a weird episode doing my suspension levels - the car did lock out the dampers and had NO movement at all - very odd - I got worried - and drove on the drive with no suspension somehow hoping it would get over itself in the morning BUT it hadn't. I started again and it seemed to go normal

forth attempt I did get it all level and oddly it feel soft and squidgy to bounce each corner - but drives like it isn't - BUT its close to how it was before I did that and I put the shocks and shudders down to the rear left now an 1" back where its supposed to sit

the change from 17" to 18" wheel size was MUCH more than the difference between Sport and Comfort... the bigger wheels look much better - and visually I can't see how they ever sold the car on 17" wheels - but when you drive it the smaller wheels are light and day better and the comfort and noise change suites the car - and you can drive it MUCH faster MUCH more safely on the roads I'm subjected too


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