Have been trying to find the right shock springs for my TY250. Have a couple sets of shocks with good dampening and am trying to find the spring that would go with my 160# weight. I have three sets of springs: The wire size seems to determine the spring rate: .280 wire in the spring give it to much rebound (bounce). .260 works o.k., .240 also seems to work o.k.

Does anyone know how they rate springs?

Also.....does it make any difference if you run the shocks inverted? This would clear the exhaust better.

Thanks in advance.

Alan

Alan springs are rated by the amount of force it takes to compress them a certain distance. Common units are pounds per inch or newtons per mm.

You should probably aim for two things with your TY250 springs:

Shockies approx 40% to 50% compressed with you aboard and balanced

With no-one on the bike, the rear suspension should sit almost topped out (about 5mm from the top)

The sequence to use is to set the preload to give the 5mm static sag and then see how far they compress with you on board. The ones that compress 40% to 50% with you on board are the best.

The rebound issue you mentioned is more likely to be a problem with a lack of rebound damping than with the spring rate.

About the relative stiffness of your springs, spring rate (stiffness) is proportional to the wire diameter, but it is also inversely proportional to the total length of the wire (coil diameter x pi times x number of coils).

Wire diameter up - stiffness up

Coil diameter up - stiffness down

Number of coils up - stiffness down

If you want to work out what rate your springs are, just google spring rate calculation and you will find a formula to use.

Some shockies damping works with the shockies either way. Some work only with the rod at the top, some only with the rod at the bottom. If you test them by hand with the springs off, you should be able to tell what is happening.

I went through an exercise of measuring or calculating spring rate on a number of twinshock and modern bikes.

The twinshock averaged around 19 to 20 lb/in and the modern are 22 lb/in.

I then got some made up by my local spring maker to put modern spring rate in my twinshock forks.