Shocks and struts measurements

[Duh_Vinci]

Cheers all!

Since R129 and W124 share many suspension components, I don't think I could find any better place to ask. I want to "upgrade" shocks/struts on my 1995 R129 SL500 to a "sport" shortened version, but there are NO options for R129 (other than a full special order B12 kit)

I'm willing to do an unorthodox experiment with W124 shocks/struts on this car, but need some preliminary measurements...

Does anyone here have some original W124 shocks and struts in the garage and could possibly offer me the measurements of these units fully extended A and fully compressed B? Front and rear if possible (rear off the non self leveling I'm assuming)?

Here is my thought process, after doing some numbers searching, Koni for example, for the front, does not differentiate between any W124 from 1985-1995, be it 260E or E500, so valving is not my concern, and physically, struts will bolt right up. Shaft lengths is the unknown for me...

Regards,
D

 

[gsxr]

D, every 124 strut I've seen when fully compressed goes ALL the way in. So there really isn't a "B" measurements.

"A" varies depending if the strut has internal rebound/extension limiting springs, which are only used on the E500E in the 124, but I think most (all?) 129's have this.

I would highly recommend you avoid KONI, unless you enjoy warranty replacement work. Oh, and if you are looking for struts on a 129 chassis, I'd go with the OE units... dunno if any aftermarket will have the internal springs.

 

[Duh_Vinci]

Thanks for the info Dave, appreciate the education! What started this, I recently replaced stock shocks on W202 C280 with B8 units+H&R springs. It is such a nimble, precise and sure footed car now, neither one of my R129's handle as such, both H&R but stock shocks/struts... Bilstein told me that they can build B6 on special order, but B8 can only be purchased with B12 kit, where I really don't need the springs. Deep inside, I was hoping for Koni or Bilstein W124 units to work on R129.

So since most W124 front struts use no limiting springs, are limitations then relied upon bump stops like the W201 (I remember I had to order burgundy/red colored one looooong time ago on my old 2.6 when I used B8's with Voigtland springs)?

Regards,
D

 

[gsxr]

So since most W124 front struts use no limiting springs, are limitations then relied upon bump stops like the W201

The external foam stop buffer (bump stops) on the shafts limit compression. The internal springs control extension, and also reduce total extension. These are opposite ends of the damper movement.

The internal springs are designed for use at a specific ride height; if the car is lowered significantly it reduces the effectiveness of the internal springs. This is likely why the AMG E60 received different struts/hydrolegs; not only are they probably valved differently, the springs may be a different length as well to match the ~10mm lower ride height. Nobody has ever cut open one of each to compare so we may never know for sure.

The internal springs may have been phased in a couple years into 129 production, as I don't see it mentioned in the 1990 Model 129 Introduction manual. But my one 500E came with R129 struts installed that had the internal springs, so I know they exist. It was an OE MB 129 strut made by Bilstein. The internal springs are shown in more detail in the 036 Intro manual, see attached.

 

[Duh_Vinci]

...The internal springs may have been phased in a couple years into 129 production, as I don't see it mentioned in the 1990 Model 129 Introduction manual. But my one 500E came with R129 struts installed that had the internal springs, so I know they exist. It was an OE MB 129 strut made by Bilstein. The internal springs are shown in more detail in the 036 Intro manual, see attached...

Thank you Dave, very interesting piece of information!

This internal springs design as in the illustration you've shared would also account for the premium $$ for later R129 Bilstein units when compared to a basic W124 (non .036 units) that do not use such design. I know that the very early R129 factory right height setting was considerably lower from the factory when compared later cars...

Regards,
D