Should I upgrade to air suspension?




I currently have H&R springs on my W212 to remove some of the wheel gap, as I have S Class wheels on my car. Without the springs it looks absolutely horrendous. Being almost 40 years old, gone are the days of sports modding my cars. now im looking only for comfort really. That being said, the lowering springs are quite harsh when driving on bumpy roads. Especially in Connecticut where the roads are really bad in some areas. My question is: would it be worth getting air suspension and then ordering lowering links to remove some of the gap? I understand that with the lowering links I can actually lower the car as much as I want, so I don't have to be as slammed to the ground as I currently am. I can just lower it half an inch or so.
Any opinion will be greatly appreciated.
If you can sacrifice the looks, you can switch back to stock springs. And I would highly recommend you pair them with Koni Special Active shocks. These shocks are amazingly smooth over bad roads. They also firm up pretty well during cornering, so your handling isn’t as boaty as stock.
While you can use the Special Actives with lowering springs, it’s not recommended at all. The shocks firm up when contacting the bump stops, and the lowering springs reduce your available shock travel, engaging the bump stops sooner. You can trim your bump stops to restore some travel, but you must be careful to ensure you have adequate material remaining so that you don’t bottom out and damage your suspension.
Some other things you can do to improve comfort is to downgrade your sway bars and get taller side walled tires.




If you can sacrifice the looks, you can switch back to stock springs. And I would highly recommend you pair them with Koni Special Active shocks. These shocks are amazingly smooth over bad roads. They also firm up pretty well during cornering, so your handling isn’t as boaty as stock.
While you can use the Special Actives with lowering springs, it’s not recommended at all. The shocks firm up when contacting the bump stops, and the lowering springs reduce your available shock travel, engaging the bump stops sooner. You can trim your bump stops to restore some travel, but you must be careful to ensure you have adequate material remaining so that you don’t bottom out and damage your suspension.
Some other things you can do to improve comfort is to downgrade your sway bars and get taller side walled tires.




Right now, as your car currently sits, I’d want you to take some measurements (front and rear) from the center of the wheel (hub) to the fender directly above. Record these measurements because it’s your reference point for this spring.
When you have the shocks and springs off, I want you to reinstall a used shock (without dust boot, springs and bump stops) and use a floor jack to compress the shock by lifting at the control arm. Compress it until you achieve the measurements you recorded. This simulates your car when it’s on the ground wearing those springs.
Then look at the shock and take a measurement of the amount of shock shaft travel remaining. Your bump stop needs to be shorter than this length, or else it’ll be making contact at ride height.
Depending on the stiffness of the bump stop used, you can trim it more or less to delay when it gets activated. The stiffer the bump stop, the more sudden and noticeable they are when they begin to compress (and vice versa). On the flip side, the softer bump stop will easily reach its incompressible height and possibly shorten the lifespan of the shock, or make tire and fender contact. Trimming a bump stop will increase its spring rate, btw.
I use the bump stops from this page on this website:
https://www.resuspension.com/bump-st...ot-series.html
Dont bother checking their other bump stops that aren’t in the COT series, they’re all tailored towards the racing crowd. The COT stuff works with OEM street rates.
I assume your 212 is a MacPherson strut up front, so you’ll need the 22mm inner diameter RE stop there. I don’t know what your rear shock’s shaft diameter is, but I assume the other stops will fit.
Here is a link to the load and travel graphs of their COT bump stops
https:/www.resuspension.com/media/wysiwyg/tech_info/bump_stops/graphs/OEM/OEM_ALL.pdf
The method I typed above is really only a quick and dirty way. The proper way involves getting corner weights and motion ratios of the spring and shock. Then you can calculate your approximate height and load requirements of your bump stops.




Right now, as your car currently sits, I’d want you to take some measurements (front and rear) from the center of the wheel (hub) to the fender directly above. Record these measurements because it’s your reference point for this spring.
When you have the shocks and springs off, I want you to reinstall a used shock (without dust boot, springs and bump stops) and use a floor jack to compress the shock by lifting at the control arm. Compress it until you achieve the measurements you recorded. This simulates your car when it’s on the ground wearing those springs.
Then look at the shock and take a measurement of the amount of shock shaft travel remaining. Your bump stop needs to be shorter than this length, or else it’ll be making contact at ride height.
Depending on the stiffness of the bump stop used, you can trim it more or less to delay when it gets activated. The stiffer the bump stop, the more sudden and noticeable they are when they begin to compress (and vice versa). On the flip side, the softer bump stop will easily reach its incompressible height and possibly shorten the lifespan of the shock, or make tire and fender contact. Trimming a bump stop will increase its spring rate, btw.
I use the bump stops from this page on this website:
https://www.resuspension.com/bump-st...ot-series.html
Dont bother checking their other bump stops that aren’t in the COT series, they’re all tailored towards the racing crowd. The COT stuff works with OEM street rates.
I assume your 212 is a MacPherson strut up front, so you’ll need the 22mm inner diameter RE stop there. I don’t know what your rear shock’s shaft diameter is, but I assume the other stops will fit.
Here is a link to the load and travel graphs of their COT bump stops
https:/www.resuspension.com/media/wysiwyg/tech_info/bump_stops/graphs/OEM/OEM_ALL.pdf
The method I typed above is really only a quick and dirty way. The proper way involves getting corner weights and motion ratios of the spring and shock. Then you can calculate your approximate height and load requirements of your bump stops.
Trending Topics
I tend to forget some things… such as this: ideally you’d want to have the front and rear bump stops make contact at the same time, so that one end doesn’t become wildly stiff and change the handling characteristic.
I’d like to share a YouTube channel that’s been instrumental in helping me learn a lot of this stuff:
https://m.youtube.com/@SuspensionTruth/
Bump stop tuning has long been misunderstood, and it still kind of is, but my eyes have been opened to the possibilities with this stuff.
On my other car, I have the Koni Special Actives with stock springs. I’ve tuned the bump stops to engage after 0.75” of wheel travel. Even with a monoball rear suspension and 35 aspect ratio 18” tires, the car handles extremely well and its behavior is very predictable. The car is strictly a street car and the roads are atrocious: lots of rippled surfaces, broken pavement, potholes, expansion joints, etc. Yet the comfort is better than when it was on Bilsteins and rubber bushings.
The Best of Mercedes & AMG




I tend to forget some things… such as this: ideally you’d want to have the front and rear bump stops make contact at the same time, so that one end doesn’t become wildly stiff and change the handling characteristic.
I’d like to share a YouTube channel that’s been instrumental in helping me learn a lot of this stuff:
https://m.youtube.com/@SuspensionTruth/
Bump stop tuning has long been misunderstood, and it still kind of is, but my eyes have been opened to the possibilities with this stuff.
On my other car, I have the Koni Special Actives with stock springs. I’ve tuned the bump stops to engage after 0.75” of wheel travel. Even with a monoball rear suspension and 35 aspect ratio 18” tires, the car handles extremely well and its behavior is very predictable. The car is strictly a street car and the roads are atrocious: lots of rippled surfaces, broken pavement, potholes, expansion joints, etc. Yet the comfort is better than when it was on Bilsteins and rubber bushings.
Also just checked if they make shocks for my W213 4Matic. Unfortunately they don't
It's actually very hard to find W213 4Matic lowering springs or aftermarket shocks for that car specifically. I was hoping Koni would at least have something for options.








Went from a 212 on stock spring suspension to a W205 with airmatic.
Nothing has gone wrong yet, but no.









I’ve ordered some shocks that another user recommended in this thread. I’ll see how they stack up to the Bilstein ones I have currently.


