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+--- Thread: Spring rates (/showthread.php?tid=262)
Spring rates - Gasoline Fumes - 03-02-2009
Using this calculator, I determined the front spring rate of my 1985 300D to be 384 lbs/in. Does that sound about right? I want it a lot stiffer, but I don't know how much is a lot. Maybe something around 500-700 lbs/in? I guess the actual wheel rate ends up being about half the spring rate because of where the springs are. Anybody think it's possible to move the shock to the spring location and convert to coilovers? It would have to be a short shock to fit there.
I haven't measured the rear springs yet.
RE: Spring rates - winmutt - 03-08-2009
IIRC the vogtlands were 70kg. Check the FSM, there were 8 different spring configs up front. 22 for the rear.
RE: Spring rates - Gasoline Fumes - 03-08-2009
70kg per what? 70kg/cm would be 392 lbs/in, if I'm doing the conversion right. 70kg/mm would be 3920lbs/in!
I don't know if any of the factory springs would be what I'm looking for.
RE: Spring rates - winmutt - 03-08-2009
http://www.mercedesshop.com/shopforum/showpost.php?p=1388801&postcount=59
Quote:Essentials of today's email.. Vogtland in italics, my response back. All productive feedback appreciated.
We presently have the 4 cyl. application designed. 200 - 230 model. I believe that these would only be Grey Market cars.
Designed for the Diesels? 114 chassis Gasoline, 115 chassis Diesels.
The 115 chassis covers models 200/220D through '73, 240D through '75, and 300D through '76.
These springs would definitely work for the 123 240D (4 cylinder 616), with minor modification.
The front rate is 47 N/mm (268 lb/in) and the Rear is 62 N/mm (354 lb/in)
Many thanks for the hard numbers, will definitely be posting these on the forum. Let you know about any feedback.
Most US models were either 6 cyl. or Diesel. We figured that these would be pretty close as far as front load. The big difference would the 4 dr. vs. Coupe. I assume that spring pads could take care of the difference in ride height. We have preliminary design data as well for these. We were targeting 49 - 51 N/mm (285 lb/in) and 64 N/mm (365 lb/in) front and rear respectively.
Some 124 Diesel folks tried using your 6cyl Gasoline application with poor results because of lowered ride height.
It was concluded that this was due to the increased weight of the Diesel engine (5cylinder 602, 6cylinder 603).
There are three different spring pads to change ride height in the rear. Most were interested in a moderate 30-35mm drop.