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I run the KW height adjustable springs and I think the car rides great.. Comfort is comfort and sport is sport and sport+ is sport+ just better handling all around.
The stiffer KW rear race springs [optional] are exactly what the car needed to eliminate any feeling of understeer in my opinion.
I ran the KW sleeves on my GTS, then switched to the Renntech ones and was much happier. I did a write up on it last year
AHI, couldn’t find that thread. Could you post impressions again please.
Here in atlanta, I’m running into installer issues and have reconsidered renntech sleeves from a Benz dealer as shim kit seems to be in order. I was told by renntech engineer that rears are sprung less and fronts more than stock.
And then then there’s the weistec sleeves which have progressive front springs in that the first few inches of travel up front have a smaller diameter spring.
Last edited by AMG 17GT; Jul 19, 2018 at 06:08 PM.
I run the KW height adjustable springs and I think the car rides great.. Comfort is comfort and sport is sport and sport+ is sport+ just better handling all around.
The stiffer KW rear race springs [optional] are exactly what the car needed to eliminate any feeling of understeer in my opinion.
no offense sir, but your running 50psi with race springs in rear. I’m not sure that’s where I want to go on ride quality lol.
I measured of the dimensions of my car's stock springs (with the P71 dynamic package) to estimate the OEM spring rates. It seems like it's in the 45-50N/mm range with the rates being the same front and rear.
@ronin_amg Do you know what spring rate or part number you went with for the "race" set of rear springs? From the looks of it, the standard setup for the KW HAS is already stiffer than stock in the rear with 50N/mm fronts and 60N/mm rears. How does it ride in Comfort mode? does the rear oscillate from the higher rate?
@AHI I read the other thread you started. About the KW's, you said it rode well at a higher ride height but it wasn't good at a lower setting. Do you think its possible that you were hitting your bump stops which caused some unpredictable behavior? Or do you think it's just that the dampers were under-damped for the higher spring rate of the KW's and causing oscillations?
I talked to renntech and they confirmed rears were softer and fronts stiffer.
After install and parts I’m looking at 3500$, for an inch lower. Under most circumstances I would pay that for another inch, just not now..... yeah yeah.
Yes, I called them too and that's all they were able to tell me. I had a look at their product photos and took some measurements. It seems like they're running 2.5" Eibach ERS springs with rates around 74 N/mm front and 44 N/mm rear. Part of the reason they went with softer rears is to allow the car to be lowered without having the more complicated setup with a helper spring like KW and Weistec.
I also looked at the Weistec setup and they're running VERY high spring rate rears. The fronts are maybe like 30% stiffer but the rears are more than double the rate of stock. I'm going to stay away from that setup. That's likely why 300blackout mentioned the shift in comfort.
KW uses 50N/mm front and 60N/mm rears which is quite close to stock. If I find I don't like the balance and want to run a softer rear, I can always swap the front and rear springs. The only effect that will have is it will limit how high or low my car can go but it's only a 10-20% height difference. There's no way you can swap the front and rear springs for the Renntech setup because of the lack of helper spring in the rear.
I think the best bet for me is the KW HAS, its more flexible (because I can swap front and rear springs) and it also can be had for ~$1200 shipped which is a good $300+ cheaper than the Renntech setup.
Yes, I called them too and that's all they were able to tell me. I had a look at their product photos and took some measurements. It seems like they're running 2.5" Eibach ERS springs with rates around 74 N/mm front and 44 N/mm rear. Part of the reason they went with softer rears is to allow the car to be lowered without having the more complicated setup with a helper spring like KW and Weistec.
I also looked at the Weistec setup and they're running VERY high spring rate rears. The fronts are maybe like 30% stiffer but the rears are more than double the rate of stock. I'm going to stay away from that setup. That's likely why 300blackout mentioned the shift in comfort.
KW uses 50N/mm front and 60N/mm rears which is quite close to stock. If I find I don't like the balance and want to run a softer rear, I can always swap the front and rear springs. The only effect that will have is it will limit how high or low my car can go but it's only a 10-20% height difference. There's no way you can swap the front and rear springs for the Renntech setup because of the lack of helper spring in the rear.
I think the best bet for me is the KW HAS, its more flexible (because I can swap front and rear springs) and it also can be had for ~$1200 shipped which is a good $300+ cheaper than the Renntech setup.
great info sir. But are springs progressive from KW. ?
No, they're not progressive on the KW. The pitch of the coil stays the same which is indicative of a linear spring rate. For the rear, it has a helper spring which is fully compressed when the weight of the car is on it. It's primarily there to keep the spring seated when the car is jacked up or if you happen to jump the car.
I measured of the dimensions of my car's stock springs (with the P71 dynamic package) to estimate the OEM spring rates. It seems like it's in the 45-50N/mm range with the rates being the same front and rear.
@ronin_amg Do you know what spring rate or part number you went with for the "race" set of rear springs? From the looks of it, the standard setup for the KW HAS is already stiffer than stock in the rear with 50N/mm fronts and 60N/mm rears. How does it ride in Comfort mode? does the rear oscillate from the higher rate?
@AHI I read the other thread you started. About the KW's, you said it rode well at a higher ride height but it wasn't good at a lower setting. Do you think its possible that you were hitting your bump stops which caused some unpredictable behavior? Or do you think it's just that the dampers were under-damped for the higher spring rate of the KW's and causing oscillations?
My rears are now 70N/mm, I think the ride is great and the dampers are fine in any setting. I have not hit the bump stops and have removed the rear helpers. I got a pair of lower spring seats used on the front and am using them in place of the helper spring seats...
Here are the KW rear springs, they are interchangeable with the fronts if you want to stiffen up the front end....
Last edited by ronin amg; Jul 28, 2018 at 01:58 AM.
My rears are now 70N/mm, I think the ride is great and the dampers are fine in any setting. I have not hit the bump stops and have removed the rear helpers. I got a pair of lower spring seats used on the front and am using them in place of the helper spring seats...
Here are the KW rear springs, they are interchangeable with the fronts if you want to stiffen up the front end....
just an FYI, I complete my Yellow Spring Racing coilover conversion about two weeks ago now. I ordered the 20kg spring rate for the rear coilovers but, I'm discovering that they are a little too stiff for what I'm looking for. I'll be replacing them with 14kg springs in a few days but thought I would see if someone on the forum would be interested in a set of 20kg springs. BTW, these are on a 03 s600. Please PM me if anyone is interested.
Thank you sir. I’m having this done at a Benz dealership by a very experienced AMG tech for this very reason. The extra dollars are worth it.
I had the alignment included in the final price, but what would you believe to be the ideal alignment specs with these coilovers ?
You did it right, AMG tech on their alignment rack with the correct software file for the car.....that’s what I did and results were A+.
Just verify the dealer has the shims on hand, as back in fall of 2017, there were only 3 or 4 boxes available in USA, so I had to have 1 set transferred in from west coast the other from East coast when we did my alignment.
As far as specs, via memory I don’t recall, think I may have print out packed away somewhere, but I believe we were in the higher side of the “green” box for camber....you’ll see what I mean when car on rack, there is “red” “yellow” and “green” to help with adjustments that are in the racks screen guiding tech towards acceptable specs.....assuming the GTS software is being used.
Alignment can be set to suit your needs: pure street alignment; aggressive street/light duty track alignment, or heavy duty track alignment.
If you go with a combo street/track alignment of around -2.3 to -2.5 camber all round, two boxes of shims should be enough especially if ride height is lowered. If you want to go more aggressive for primarily the track, then you’ll probably need four boxes of shims; (they aren’t cheap btw).
I’m running -2.5 camber at all four corners and am very happy with it for all purposes. Can’t remember my caster and toe settings but I didn’t want the car to be ‘nervous’ on the street so they aren’t too aggressive.
It is best to wait a couple months before completing the alignment, the springs need 300-400 miles or a couple months of sitting to settle in place. If you perform an alignment the same time as installing new springs you may have to go back for a new alignment. I just installed Renntech springs yesterday. I am waiting for spring to adjust the alignment. I started with a 1/2 inch drop. The photos below are after installation.
I haven’t noticed a difference on the road, but its only been a day. I am happy with the current stance though Im sure it will drop slightly, so I am trying to be conservative. After going back and forth on what spring/shock set up to buy I decided a single, progressive spring suits my balance between comfort and sport. The car is driven on the street but does see a fair amount of track time. I am anxious to see how the Renntechs perform at the limit. My goal was to reduce the amount of load transfer during heavy braking and corner transitions. My first track day of 2020 will be in April, we shall see, but I feel confident they will turn out great.
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