How to measure spring rates?
 

Just wondering how could I measure the spring rates of the coil springs of my touring cars...Do I need to buy special equipment or there is an easy way to do so? Thanks

You can squeeze them against one another to see what is stiffer. You can measure the wire diameter, internal diameter and number of coils to try and calculate the rate. To actually measure the rate is hard with the equipment you might have available at home although I think some people have fabricated a jig using a drill press and a kitchen scale.

Idea, trying to convey in words.

Place spring over a hole in a board. Put long screw with fender washer through the spring and hole. Hang weights off the screw (don't forget to account for the weight of the screw/washer) and measure the deflection of the fender washer relative to the board.

Spring rate, k = weight/deflection

It's a good idea to place both springs over a screwdriver, nutdriver, socket wrench extension, etc, when doing this. Otherwise they can fly really far when they go BOING.

Here is a thread that shows my spring tester and has a spread sheet to calculate spring rates. http://www.hobbytalk.com/bbs1/showth...ghlight=spring

Looks great! Simple but effective.