drakon

I just picked up my SLK55 yesterday, and i'd like the ride to be lower, and a little stiffer. Would it be okay to cut a coil off, and change to thicker spring pads?

it works on older cars, any reason it won't work on this car? I know renntech and lorinser used to do this with several cars (including my 1990 560 SEC, full AMG hydro system, but renntech cut a coil off).

Tommy_s4

any more pictures of you 560?

ClayJ

DO NOT DO IT!!!!!!!!!!!!!!!!!!!!



On a car like an SLK55 you either change your wheel and tire sizes, or you buy CORRECT FITMENT 'lowering' springs to achieve the desired effect without RUINING YOUR CAR AND ITS RIDE.

OnyxCLK

are you crazy??? it's dangerous to cut the springs... the car will become unstable.. I have a couple of friends who are had serious accidents after losing the control of the car because of the springs, they were all cut...

benzmodz

The spring will get softer with fewer coils. It will be less compressed in position. Not only that the camber will be out so there is a risk of popping the spring out at higher speed.

Get it done properly and live to tell the story.

drakon

Hmm...with normal springs, they get STIFFER with fewer coils...Do SLKs have special springs? Why would the camber be out? i would use the factory spring pads to bring the height back up a little bit.

Why would it be dangerous to cut springs? I KNOW this can be done with older cars, does the SLK have some sort of special situation? Are the springs progressive rate springs on both ends?

Anyway, i'll take your guys' word for it...but i'm still curious as to why this doesn't work for modern cars. I'm googling it right now...

Bigdot

idk on the SLK, but on my R129, there is acually a line on the spring where the machanic CUTS the spring for the "Sport Package" but teh SLK might be diffrent.

Mark

drakon

Thanks red mongoose.

anyhow done some googling, and apparently, springs CAN be cut to be lowered under certain conditions:

1.) the end you cut ISN'T progressive (tighter and tighter coils)
2.) you don't cut too much off (depends on car, for most cars too much would be more than an inch of compressed spring, or more than one coil)
3.) the end you are cutting isn't flattened by a factory.

reasons:

1.) cutting a progressive spring WILL ruin the characteristics of the spring
2.) cut too much and stock shocks and camber is hurt, and the spring will be too stiff
3.) if the end was flattened and you cut it off, then it will pop out of the mount.

so i guess the next thing to do is to take one of my spring out and look at it....

Easty

A lot more goes into these springs than you think. There analysed as a volume of material and process at the end for rigidity and interfacing wear. and softer in the middle to deal with the harmonics.. The fact you can just chop them to achieve the same performance as a specifically designed spring is very unlikely.

ClayJ

I will repeat:

Cutting the springs on an SLK55 is lunacy.

On some other cars, and with experience? Maybe.

On a racecar and with alot of experience? Sure.

On an SLK55? No way in Hell!

SLK55R

you just bought a SLK55 ... spend a little bit of money and get real springs or a coilover system.

JamE55

Your car ain't no rice.

drakon

Okay Okay, you guys have convinced me....

Bigdot

yea u are better off just spending the 300ish on new springs, the only reson that i went custome, is that the ones that are made for the 129, hardly even lower it, and i wanted it much more agressive.

Mark

benzmodz

Look at it this way. The displacement of the control arm to the body remains a constant. What you are suggesting is that you will install a shorter spring into the same distance. Therefore the spring will be under less load - even with the spring pad you refer to.

What people often mistake as a stiffer ride is in fact a rougher ride with decreased suspension performance. The spring relies on suspension travel to provide its function. With fewer turns the rebound is lower (basic law of physics) and the harmonics / vibrations of road travel are transferred back into the chassis more directly.

This does not mean that the wheel is holding the road but does mean that the chassis is now absorbing more stress. The dynamic of the chassis is then affected so that it can affect the performance of the other 3 wheels.

Taken as an extreme ......



There have been some problems with ABS and ESP cause by

1/ decreased contact patch / increased camber

Remember that the contact patch is meant to be a stable pattern in order for it to work. If it is normal at low loads and decreased at high loads then you will get unstable handling.

2/ Braking issues

The ABS system gets extremely confused when grip is lost in the wet and the car wont stop even with ABS and ESP fully active. This is because the tyres are not performing correctly according to the onboard control system parameters.

3/ Bump stops

AS you experience higher loads the spring will be more easily compressed (since it has fewer turns for the same car load) and the shock may hit the top of the suspension. This not only damages the strut but also means that you have run out of shock adbsorbing capacity.

I did it once on my W203 when my shocks hit their limit the car was completely smashed under the engine. This was caused by a dangerous road not cut springs. With cut springs you have less chance.