Coil spring specifications

[Audiophile]

For those running firmer springs what specifications (both front and back) are you running in terms of:

Number of Active Coils
Wire Diameter
Outside Diameter of Spring
Free Length
Spring Rate

and are they progressive or linear.  Where did you buy them and did they require any trimming?

Thanks you.

[rjmarco]

Not sure if these are high performance but I just ordered and received two front coil springs from MB Classics.  The part number is:  108 321 03 04.

I'm currently having these installed in my 1965 230 SL.  Was tough removing the first one since some rust had fused the lower coil in place.

Regards,

Rich

[Audiophile]

Rich,

That part number is for a 280SE Cp so it is likely firmer.   How many coils does it have (start with the first full coil to the last full coil plus the partial coil at the end, so it could be 8 full coils plus 1/2)?  The specs on that spring is:

Thickness [mm]15,9
Length [mm]410
Outer Diameter 1 [mm]126

[Bob G ✝︎]

I was told I had the wrong coil springs in my 1968 280SL. I had my Mechanic get new spring but they are 108 sedan springs. How will that effect  the ride height and driving.
I have old pictures of the front of my dad's car which is now mine when it was new there was enough room to slide you hand in between the front tires and fender lip. I took out the originals in question. I put in John Olsens springs then brought the car to the classic center to have them put back what was originally in the car. It had a nice rear negative camber to it in the rear. I think the classic center mess up. The SL would drift at 60 MPH  did not do this before I put Oson's springs in I think I messed up ever thing. Hard to believe every one not sure of the correct springs car is in San Diego being worked on by Bob Onager. He told me the springs were wrong and that I need new springs to have the alignment done?
Bob Geco
sorry for babbling on with this conversation.

[stickandrudderman]

This is something I've just started looking at.
In motorsport one uses different springs for different tracks/drivers/conditions and the key difference is the spring rate.
Spring rate is defined as the amount a spring will compress when subjected to a given load.
I recently bought a spring rate tester with the intention of deducing the spring rate of any new springs that I fit in order to compile data. I'll get some springs from Mercedes and some from SLS and compare them. Once the data is accumulated I can appraoch a spring supplier with the correct specification to see if the correct springs can be had at a better price than the exorbitant Mercedes prices or indeed offer a different (but known) rate for those that require a different fitment.
It'll take some time though.

[JamesL]

Stick and others...

There's a load of old discussions on here about spring compression - in particular relating to progressive springs...
http://www.sl113.org/forums/index.php?topic=77.0

[mdsalemi]

Jim Villers (he posts here now and then) did a lot of work with springs some years ago, and came up with some relatively inexpensive solutions. There are many custom spring winders around, so if Stick comes up with some hard number specs, somebody is there to fabricate to them.

http://www.coilsprings.com
http://www.pohlsprings.com/coil_springs.html
http://www.bettsspring.com/automotive-aftermarket
http://www.springworks.com/auto-rare-coil-buy.html
http://www.eatonsprings.com

[Audiophile]

Of all the posts I have seen no one really posts any specs that a spring winder could manufacture to.  It seems it is all very general.  For example John Olson's springs are progressive but what are the specs?  I haven't seen any specs from Mercedes on the OEM springs either.  It would be nice to have the original specs and compare them to what is being tried by the different forum members and their impressions as well as ride height.  I have seen many cars that I believe are too high after suspension work.

[DaveB]

The technical data manual 1966 lists comprehensive spring specifications for 230sl. I'll post photos of the charts when I find my camera but for now here are those for front springs:

front spring standard 113 321 04 04, free length 387.5mm, installation height 253 +5/-2 mm, load "P" normal 611 kp, load "P" max 946 kp, spring travel per 100 kp load 21.9 mm, wire thickness 15.6 mm, mean winding diameter 110 mm, number of windings 9 3/4

front spring HD 113 321 05 04 , free length 366.1mm, installation height 255 +/- 9 mm, , load "P" normal 607 kp, load "P" max 1011 kp, spring travel per 100 kp load 18.21 mm, wire thickness 16.2 mm, mean winding diameter 110 mm, number of windings 9 1/2

[stickandrudderman]

I've seen the other discussions James but Dave's post above illustrates the kind of data we need and as Mflaten suggests, it is, so far, lacking.

[DaveB]

Spring specifications below:

[stickandrudderman]

Perfect, that's saved me a lot of time. Onya Mate!

[mdsalemi]

I believe that information from Dave, could go directly to a custom spring maker and it they had questions--go to another custom spring maker!  Seems to cover it all!

[stickandrudderman]

I've finally got around to compiling some data and the results are interesting!
I've bought new front and rear springs from SLS and Mercedes plus I had one new Mercedes one in stock.
The SLS ones are some 10% stiffer than the original ones (front and rear)
Now the interesting bit: All of the front springs I have measured (3 MB, 2 SLS and 2 removed from a car) have given consistent readings in that the old springs were exactly the same as the new MB ones but the SLS ones were 10% stiffer. However, of the rear ones I measured only the SLS ones gave consistent readings. The rear springs that I removed from the car gave different readings by about 10 pounds/inch. The SLS springs gave consistent readings but were 10% stiffer and the 1st pair of MB springs I measured were softer than the old ones I'd removed from a high mileage car and were 20 pounds/inch different to each other! I asked MB to send me another pair which arrived today and guess what? They too were not only different to each other but both were different to the other two! The difference between the softest NEW spring and the hardest NEW spring was 16% and the hardest spring was 10% softer than the SLS spring!!!
At the moment I'm faced with fitting one old spring and one new MB spring to get a balanced rear pair for my customer without stiffening the ride.
Further, if one searches the information held on this site, one finds that even the SLS springs are softer than the original MB spec!
I am a factory trained MB technician and have for 30 + years advocated fitting parts by chassis number/part number. I'm beginning to think that I might have to re-evaluate my thinking.

[ja17]

Yes, I heard that  the inconsistancy of the original springs is why the factory uses the color coding system. Each spring is measured and then color coded so it can be used with a similar mate to make a pair.

[stickandrudderman]

If only that were true! Of the four springs I've measured there are only two different colour codes, three with a single red spot and one with a blue spot but all are different!

[stickandrudderman]

An update.
I filed an official complaint with MB(UK) which they in turn forwarded to the Classic centre in Germany.
The response?
"Nothing wrong with them mate".
Unbelievable.

[Bob G ✝︎]

Glad some one took the time to look into this matter. I been plagued with bad luck for 5 years trying to figure out what coil springs were in my
1968 280SL.   If I had  not messed with it and took it to my fathers mechanic to put the John Olson springs spring in it work of bee fine . The car sat just right negative camber was right on in the rear and specification according to what I took when I purchased the Olsion springs . After that I took it to the classics center to have Jeff put the coil springs back and correct the ride height. When I got the car back it would have  an unsecured feeling at speeds of 60 MPH and I was constantly  making corrections to keep the car in my lane . The classic center said  and I quote from my conversation from Jeff " your king pins are worn out and need replacing " end  quote. not wanting to do this right away I drove the car but was very unhappy. no mention of what coil springs I handed to Jeff. The car sat too high and had positive camber in the rear. then at a Club  meeting I meet Bob Onager . Told him about the problem he suggested starting all over again checked my King Pins and said and I quote, they are fine I put grease into all the nipples and he recommended even pushing the envelope that at this time there is no need to switch them out for new ones. We purchased new MBZ 280SL Springs after a week of trying to figure out why one side in front was dipping he went to an alignment shop everything was a ok. no bent frame parts. The trick was funny switch col springs in front  the soled the problem and know the car sits correct to specification.
I still intend to research the spring that were  in the car when I got them they appeared to bee factory coils springs.
I when thought a night mare trying to figure out what was happening and why. I may substitute  Koni shocks fro the new Brillstein's u put in a year ago.
Glad some one took this subject seriously.
Bob Geco