Originally posted by NiMo
not sure about lbs, but the part numbers indicate the pressures.
1st 2 the winds, 2nd 2 the pressure.
3517 = 3½ turns and 1.7 pressure.
1st number is the the # of turns, 2nd number is actually the diameter of the wire that makes the spring (i.e., bigger diameter and less turn is stiffer than smaller diameter and more turn).
So 3517 = 3.5 turn of 1.7mm wire.
Unfortunately it does not give you the lb/in.