TRF 501 Springs

[werner1619]

I have 3 sets of tamiya springs, all of them are white, first I thought all of them are the same stifness, but on closer inspection I found that each of them are marked at the top with a little dab of paint, red, yellow and blue?
Ok, so looking closer once again, i found that the red has coils that are closer than the yellow and blue marked springs. It seems yellow has fewer coils and bue the least. I can't feel a stifness difference between the 3 and would like to know if these are indeed stifness different..?

thx