Rear coil spring callculation

[MORGANpl]

Can someone here check by the VIN WDB2110222B025225 what springs i need for my car E320cdi? I mean the colour markings? I know that you have to add for all extras some points and than you will know which spring but i dont have clue how to do it.

 

[grober]

There appear to be 2 possibles
A211 324 06 04 1BLUE 1 GREEN STRIPE COIL WIRE DIAM 14.5 LENGTH 329
AND
A211 324 07 04 2GREEN 1 BLUE STRIPE COIL WIRE DIAM 14.9 LENGTH 333 [ HEAVIER DUTY?]
if you cant see any colour codes on the xisting spring try measuring the coil WIRE OD

According to EPC your car chassis with sports suspension w211022 starts off with 195 plus 25 extra =220 indicating that A211 324 0704 would be your spring -- just
significant loading would be -- thro loading 5 fully glazed sliding roof 6 emergency spare tyre 4 larger fuel tank 3


but check the xisting colour code if at all possible

 

[MORGANpl]

There appear to be 2 possibles
A211 324 06 04 1BLUE 1 GREEN STRIPE COIL WIRE DIAM 14.5 LENGTH 329
AND
A211 324 07 04 2GREEN 1 BLUE STRIPE COIL WIRE DIAM 14.9 LENGTH 333 [ HEAVIER DUTY?]
if you cant see any colour codes on the xisting spring try measuring the coil WIRE OD

According to EPC your car chassis with sports suspension w211022 starts off with 195 plus 25 extra =220 indicating that A211 324 0704 would be your spring -- just
significant loading would be -- thro loading 5 fully glazed sliding roof 6 emergency spare tyre 4 larger fuel tank 3


but check the xisting colour code if at all possible

I can't really check the rear ones. The problem i have is that I need to get springs for Saturday as the car goes to mechanic so I won't have time to swap them if the will be wrong. I wanted to get them from MB but they are £160 for both. For that price I could have Sachs ones and new glow plug relay.
If that could help the front springs I got from MB and they are A2113210504 1x green 3x yellow

 

[grober]

That would appear to tie in altho the xtra added points calculation differs front to back. Front points are 223+12 which corresponds to your mb spring Best I can do the Sachs colour codes are the same as MB

 

[MORGANpl]

That would appear to tie in altho the xtra added points calculation differs front to back. Front points are 223+12 which corresponds to your mb spring Best I can do the Sachs colour codes are the same as MB

So the rear one A2113240704 is slightly longer(333mm) than the other option(329mm). Would that mean that the rear of the car would be sitting slightly higher with those 333mm?

 

[grober]

It also has a greater coil wire cross section 14.9 instead of 14.5- however these are static unloaded dimensions. When loaded any spring will compress somewhat due to the load on it. Because the thicker longer spring will resist this compression more [ higher rated] it will take a greater weight to compress it to the same loaded height. Thats what the points system is about ----greater weight- meaning you need a slightly higher rated spring to end up with the same ride height and bump characteristics

 

[190]

That small difference of less than 3% between 14.5 and 14.9 makes a surprisingly big difference to the spring rate of something like 27%.

The reason why is evident in the formulae for calculating spring rate note the wire diameter is raised to the power of 4:

Rate formulae = (wire Diameter to power 4 * 1470000)/(coil diameter to power 3 * number of coils)

 

[BlackC55]

I can't really check the rear ones. The problem i have is that I need to get springs for Saturday as the car goes to mechanic so I won't have time to swap them if the will be wrong. I wanted to get them from MB but they are £160 for both. For that price I could have Sachs ones and new glow plug relay.
If that could help the front springs I got from MB and they are A2113210504 1x green 3x yellow

That part number cross references to Euro's number 627221330. Don't take that as gospel though, the system doesn't always get it right!

Natacha