gadget Posted June 24, 2007 Report Share Posted June 24, 2007 Hi I have a Gas Gas pampera Mark1, and wondered if any one knows if there is anywhere that i could get some stonger fork springs for it. They are the same as the ones in my 99TXT. I have tried thicker oil and spacers, but have ran out of ideas, "apart from loosing more weight!" Thanks Quote Link to comment Share on other sites More sharing options...
mcman56 Posted June 25, 2007 Report Share Posted June 25, 2007 If full compression is not near coil binding the springs, one option would be to cut your existing springs shorter. Basically a shorter spring is a stiffer spring. I have done this on a TY250 mono and a TLR200 with good results. Springs can be cut with a hot saw or small grinder. If necessary, the cut end can be made flatter by heating and bending flat or even a little grinding. You will then need longer spacers to set proper sag. Put a steel washer over the cut end because it will probably not be as flat as a spring manufacturer can make. The question then becomes how much to cut. If you can stand a little engineeringish, the formula for calculating spring force is: F = (G d**4)/( 8 D**3 n) where ** is for exponent..that is d**4 = d x d xd x d G = shear modulus = 11.5 x 10**6 PSI for steel d = wire diameter of the spring D = mean coil diameter of the spring or (coil ID + Coil OD)/ 2 n = number of active coils Since the number of coils is in the denominator, you can see that more coils makes for a lower spring force. So.... calculate the rate for the existing springs. Estimate how much stiffer they should be...(10%...20%?) Then run the calculation backwards to see how many coils to cut off. Verify that they will not coil bind with that many coils and then cut away. Quote Link to comment Share on other sites More sharing options...
mcman56 Posted June 25, 2007 Report Share Posted June 25, 2007 After pressing POST, I realized the equation can be made much simpler. For your calcuations G, D, and d are constants so: F2/F1= n1/ n2 or % increase in stiffness = (n1/ n2) x 100 or n2 = (n1 x 100)/ % increase in stiffness Quote Link to comment Share on other sites More sharing options...
scorpa3 Posted June 25, 2007 Report Share Posted June 25, 2007 After pressing POST, I realized the equation can be made much simpler. For your calcuations G, D, and d are constants so:F2/F1= n1/ n2 or % increase in stiffness = (n1/ n2) x 100 or n2 = (n1 x 100)/ % increase in stiffness Crikey!!! Quote Link to comment Share on other sites More sharing options...
mcman56 Posted June 25, 2007 Report Share Posted June 25, 2007 Crikey!!! Well, his name is Gadget Quote Link to comment Share on other sites More sharing options...
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