The case for Air Suspension Option
#28
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#30
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In Australia, non Airmatic cars have adjustable dampers on the agility select.
Similar to the w204 sports mode.
Similar to the w204 sports mode.
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2015 C300 RWD
W205 suspensions cause some confusion. if I'm incorrect, please correct me, but I understand no matter where car built it has 4 total options, 3 steel non-adjustable and one air adjustable, though they are marketed under different names or packages.
The 3 steel non-adjustable "Agility Control" suspensions which, you cannot 'control'. They're variable dampening shocks to stiffen up based on road surface and driving style. They can (and do) work well on curvy roads when you're leaning to stiffen up, but can (and do) unfortunately stiffen up more on cruddy roads when you want them to be their most forgiving too. The technology is the same as Koni FSD shocks, which have been around a while and pretty cheap to replace.
They come in luxury/comfort, standard sport, and "sport package" or AMG-style. The later in the US being least compliant and lowered about 15mm and every country seems to package these 3 variations a little differently.
The airmatic is the same globally. It has 3 different air suspension tuning levels, which all are active and based on where driver puts agility control. One of them being 15mm lower and it is adaptive via computer based on road/driving and speed, and has further option to 'raise' when touch button to clear small obstructions. What varies on this system is the tire size depending on model/country. Some reviewers, especially those on the larger wheels with airmatic are little less favorable, but most reviewers and owners on this board see it as a must have IF you can afford it short and long term. They're pricy to replace, though they can be replaced by the standard steel shocks down the road. (Videos below not specific to C class but give an idea)
The 3 steel non-adjustable "Agility Control" suspensions which, you cannot 'control'. They're variable dampening shocks to stiffen up based on road surface and driving style. They can (and do) work well on curvy roads when you're leaning to stiffen up, but can (and do) unfortunately stiffen up more on cruddy roads when you want them to be their most forgiving too. The technology is the same as Koni FSD shocks, which have been around a while and pretty cheap to replace.
They come in luxury/comfort, standard sport, and "sport package" or AMG-style. The later in the US being least compliant and lowered about 15mm and every country seems to package these 3 variations a little differently.
The airmatic is the same globally. It has 3 different air suspension tuning levels, which all are active and based on where driver puts agility control. One of them being 15mm lower and it is adaptive via computer based on road/driving and speed, and has further option to 'raise' when touch button to clear small obstructions. What varies on this system is the tire size depending on model/country. Some reviewers, especially those on the larger wheels with airmatic are little less favorable, but most reviewers and owners on this board see it as a must have IF you can afford it short and long term. They're pricy to replace, though they can be replaced by the standard steel shocks down the road. (Videos below not specific to C class but give an idea)
Last edited by floridadriver; 09-28-2014 at 09:41 AM.
#33
As far as i was able to source, (i stand corrected if someone has a better source) overall, the steel suspension, uses same* dampers for all models, but two* different types of springs.
Avantgarde+Exclusive exterior packages uses the same* springs
AMG exterior package comes with option of same springs as above, or 15mm lower stand (shorter coil springs) at no extra cost.
* dampers and springs for a given car model, often differentiate between several vehicle specifics. some examples are:
- Wagon and Sedan type.
- Models with heavier or lighter engine.
- RWD or 4WD.
Overall the difference in damping and spring rates, are often designed to level out these differences. This means you should end out with more or less the same corresponding car in terms of suspension dynamics, irregardless of the model specific choices.
Example an AMG package 6 cyl C400 sedan should in theory (in terms of suspension dynamics) drive the same as an AMG package 4 cyl C180 Wagon
Avantgarde+Exclusive exterior packages uses the same* springs
AMG exterior package comes with option of same springs as above, or 15mm lower stand (shorter coil springs) at no extra cost.
* dampers and springs for a given car model, often differentiate between several vehicle specifics. some examples are:
- Wagon and Sedan type.
- Models with heavier or lighter engine.
- RWD or 4WD.
Overall the difference in damping and spring rates, are often designed to level out these differences. This means you should end out with more or less the same corresponding car in terms of suspension dynamics, irregardless of the model specific choices.
Example an AMG package 6 cyl C400 sedan should in theory (in terms of suspension dynamics) drive the same as an AMG package 4 cyl C180 Wagon
Last edited by Pete1968; 09-28-2014 at 11:52 AM.
#34
If we assume that the same dampers are used, (again this is an assumption since i do not have access to the Mercedes Spare parts system) then we can do an example to explain why the suspension comfort is compromised with the 15mm shorter coil springs.
The Dampers "Adapt" via the two way valve system Floridadriver explained earlier.
Lowering the car with shorter springs, Pre-loads the damper, (compresses it) thereby reducing the available Compression working area. In terms of dynamics, you still get the reduced body roll. But you also reduce the dampers abillity to work at the optimum rate, which means the dampers does not absorb pot holes as well as it was intended for, and might bottom out too easily. On these types of dampers, the reduced working area, does not necessarily mean less comfort over the average road bumps. But it does limit the available lenght the suspension can travel until you hit the Bump Stops. If you load up the car with f.ex passengers, you will of course reinforce the above mentioned effects.
When driving in anger on a Track, you can often feel the failure of a system like the Koni FSDs (with too short springs) if you ride the Kerbs in corners, or do quick S-turns. The dampers are not able to sustain optimal road contact, so the car does not grip well, and feels less planted.
Of course as always the above does not apply to every suspension system. Some dampers might have more then enough available compression working area to compensate for the pre-load of a shorter spring. Some manufacturers simply supply shorter dampers with shorter springs. In this case i doubt this is the case though. 15mm does not usually warrant a shorter damper.
The Dampers "Adapt" via the two way valve system Floridadriver explained earlier.
Lowering the car with shorter springs, Pre-loads the damper, (compresses it) thereby reducing the available Compression working area. In terms of dynamics, you still get the reduced body roll. But you also reduce the dampers abillity to work at the optimum rate, which means the dampers does not absorb pot holes as well as it was intended for, and might bottom out too easily. On these types of dampers, the reduced working area, does not necessarily mean less comfort over the average road bumps. But it does limit the available lenght the suspension can travel until you hit the Bump Stops. If you load up the car with f.ex passengers, you will of course reinforce the above mentioned effects.
When driving in anger on a Track, you can often feel the failure of a system like the Koni FSDs (with too short springs) if you ride the Kerbs in corners, or do quick S-turns. The dampers are not able to sustain optimal road contact, so the car does not grip well, and feels less planted.
Of course as always the above does not apply to every suspension system. Some dampers might have more then enough available compression working area to compensate for the pre-load of a shorter spring. Some manufacturers simply supply shorter dampers with shorter springs. In this case i doubt this is the case though. 15mm does not usually warrant a shorter damper.
Last edited by Pete1968; 09-28-2014 at 12:45 PM.
#35
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2015 C300 RWD
New Australian review reference this topic. Some clear pics of the car as well...
http://www.caradvice.com.au/302466/2...z-c250-review/
http://www.caradvice.com.au/302466/2...z-c250-review/