Originally Posted by Stretch

No I get that - but - you need to know how many turns of the coil you have for each spring.

When you have a spring that has say 10 free coils that are not touching each other you've got a stiffness that is equal to say X N/mm

Compress the spring to fit it in the car and you might find that you've only got 8 free coils that don't touch each other. The stiffness will be INCREASED to say XX N/mm

If you then want to change the height again for a race situation then you may only have 6 free coils that don't touch each other so you've then got a stiffness of XXX N/mm

The over all length of the spring and the number of turns and the gauge of the wire and the mean diameter are all important considerations (assuming you know what stiffness you want from a stability calculation)

[Also if you want a height change on the front springs you'll end up with some pretty messed steering geometry / camber / castor on a standard W123 front suspension design]

Originally Posted by DeliveryValve

Nice find on the spring. Can't comment on the Math, though I think it looks good.

Looking forward to seeing the progress...


BTW - looking at the picture of the spring I see it is flatten on the ends. This will work on the top, but if you plan to use it with the stock shape MB bottom perch/plate, you may have to cut a coil off to have it seated properly.


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Originally Posted by Secondaries

Well, linear springs have equal spacing and thickness between all active coils. They should compress equally and one shouldn't touch another until they are all touching. These aren't progressive springs.

Originally Posted by Stretch

True but a coil spring is only linear when the load is applied evenly along the length of the spring. That isn't the case in a W123. Have a look at your existing springs if they are still fitted to the car. It is quite common to see them bulging a bit. This isn't a problem for the W123 under normal circumstances but if you are putting in new springs then basic things such as counting the coils and working out how likely it is that coils will touch is important.

Originally Posted by Carlos Granados

Help , I need lower springs for my w 123 , H & R don't have them , I read some were the 116 coils will fit on a 123 ,, my car have a 560 engine and 5 speed box the made it lighter , thanks

Originally Posted by DeliveryValve

Personally I don't think going to 18-19mm in the rear sway bar will not be too drastic. Both R107 and w116 has about a 19mm rear sway bar and a 24mm front sway bar from the factory. The smaller r107 handles pretty good, but has a completely different front suspension setup - rear is the same as the w116, w123, and w126.
Since I bring up the w126 chassis, the offered swaybar setup is 24 mm up front and 13 mm out back with an optional 17 mm rear on some models.
Now the w116 has a similar front suspension setup and rear suspension as the w123 and w126, but I'll tell you, I'll take the factory w116 handling over the w126 any day. My experience, those factory w116 will out corner any factory w126.
In taking what Mercedes offered, I think an 18-19mm rear swaybar will help immensely on a w123. I don't even think oversteer would be an issue with this thicker bar.




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