Front Spring Length on finding the red car!

[getsmart]

Hi all,

In another older post on this forum I found this post re front spring length

230SL Front Spring
Part # 113 321 0404
Free Length: 387.5mm
Installed height: 253 +5, -2 mm
Normal Load: 611 kp
Max Load: 946 kp
Travel per 100 kp.: 21.9mm
Wire thickness: 15.6 mm
Winding dia.: 110 mm
Windings: 9 3/4

Source: Tech Data Book 1966 ed.

I'm rebuilding my entire front end but my existing springs are measuring around 410mm? And with the top and bottom rubber mounts around 450mm. This seems excessively tall especially considering the default free spring height of 387mm noted above. Also it looks like I've got around 11 windings on mine compared to the 9 3/4 specified above.

Am I measuring them wrong? Note that I bought the car in pieces so I've not seen the original ride height.

Never ceases to amaze me the things that I'm discovering about my car as I attempt to rebuild and refurbish as much of it as I can myself.

Looks like I need new springs and now another decision to make - standard or stiffer - I'm leaning towards stiffer.

Regards, Joe

[DaveB]

Hi Joe,
Just to check (seeing as you bought the car in pieces) are you sure that's a front spring and not a rear compensating spring?
There's some spring information in this video: https://www.youtube.com/watch?v=3CTavYP8-Qk
The number of windings may refer to the active windings, i.e. not including the top & bottom turns. The 230SL front spring Jim shows in his video also has 11 windings total. But so too does the compensating spring, based on online images - I'll take a look at mine and get back.

[DaveB]

Or maybe it is a W108 front spring. All those dimensions are in the small technical book, will see if I can find.

[getsmart]

Or maybe it is a W108 front spring. All those dimensions are in the small technical book, will see if I can find.

Dave, the front axle was fully in tact when I bought the car and I disassembled it myself. Definitely not the compensating spring! Possibly w108 springs! My free spring length is a good 20mm longer than the 387mm, thats why I wondered how the free spring length is measured. I'm leaning toward stiffer front springs anyway but would like the car to sit a cm or 2 lower if possible (no tyre wheel arch rub?) so I'll probably purchase the smaller size top and bottom rubber mounts. They appear to come in 6 sizes, 32.5mm, 30mm, 27,5, 25, 22.5 and 20mm. My current ones are 25mm - 1103250285.

Thanks for checking Dave Now to see if I can purchase them locally for a fair price!!! Though purchasing non-MB might be frought with danger if there is confusion over the spring specs as per this discussion...thats why I'd like to know if anyone has any real life spring measurements (my spring thickness is as per spec btw at 15.6mm).

Joe

[DaveB]

This diagram from the technical book shows how free spring length is measured - it's not total length. So your measured total length at 410 mm would seem about right.

The book also states "the part number of the spring is embossed in the last bottom winding of the spring as well as the DB trademark"

Front spring specifications are in the second attached diagram, including those for the heavy duty spring 113 321 05 04. Rear spring specs in the third diagram (standard version 113 324 04 04, HD version 113 324 02 04, and what appears to be a shorter standard rate spring 113 324 03 04).

[getsmart]

Brilliant Dave!!! Many thanks. All makes sense now. So my springs are probably original and stock standard. I measured "L" and yes exactly 387.5mm. I'll need to clean them to see if the part number is embossed in the lower part of the spring.

Best Regards, Joe

[cfm65@me.com]

Hi Joe,
I think the 113 front springs do not have rubber at the bottom. The spring fits into the lower wishbone without a rubber. Only the rear springs have rubbers top and bottom.
Regards
Chris

Does anyone know who makes upgraded front springs?

[stickandrudderman]

The correct way to measure springs is not by length but rather by spring rate. Motorsport workshops usually have the necessary tester.

[getsmart]

Hi Joe,
I think the 113 front springs do not have rubber at the bottom. The spring fits into the lower wishbone without a rubber. Only the rear springs have rubbers top and bottom.
Regards
Chris

Does anyone know who makes upgraded front springs?

Hi Chris,

Thats a good point re no lower rubber mounts. I have no idea why I have 2 sets, definitely there were none in the lower part of the spring except for the thin ones which I guess are to stop squeaking and premature wear. I'm even beginning to doubt that they were there too? Early onset alzheimers' perhaps?

Rgds, Joe

[getsmart]

The correct way to measure springs is not by length but rather by spring rate. Motorsport workshops usually have the necessary tester.

Thanks Stick always happy to ask questions and learn!!!......and get advice from those that have experience and done it before!

Rgds, Joe