XRAY - Model racing cars

Guys,

I did the tests and here is what i found:
- the "C" rating is the spring rate in N/mm (as previously posted by David Ehrbar)
- the springs are linear rate (not progressive)

Here's the results:

C=2.2 measured 2.14
C=2.4 measured 2.40
C=2.6 measured 2.55
C=2.8 measured 2.75
C=3.0 measured 2.94
C=3.2 measured 3.13
C=3.4 measured 3.42

I put an old shock with collar into the chuck of my CNC mill and compressed the springs onto a 2kg scale with claimed accuracy of 1g. I don't know if my setup measurement error is 0.01 but that's what i measured it to (my CNC mill is very accurate and the scales claim 1g).

I measured 2 springs of each type (results were pretty much identical for each of same type).

For 2.2 and 2.4 springs i took measurements every 0.2mm, i checked the data and found it was linear so i did the rest at 1mm intervals to save time. I compressed them from 0mm to 7mm, except for the 3.0, 3.2 and 3.4 springs which went over 2kg above 5 or 6mm.

So to convert to lb/in you can just multiply the "C" rating by 5.71

C=2.2 => 12.5 lb/in
C=2.4 => 13.7 lb/in
C=2.6 => 14.8 lb/in
C=2.8 => 16.0 lb/in
C=3.0 => 17.1 lb/in
C=3.2 => 18.3 lb/in
C=3.4 => 19.4 lb/in

Hope that helps!

Chris...

Its interesting that some drivers can tell the difference between the more linear and progressive springs, when the amount of movement in a race is a few mm at most.

Skiddins