With a rate of 1kg/mm and the spring now compressed by 10mm, you would need to exert more than 10kg of force down on the fork in order to begin compressing it.įor example, if you applied 11kg of force on top of the fork it would only compress by 1mm (not 11mm) because the first 10kg of force you applied was merely overcoming what was being exerted by the spring inside the fork (as a result of it being compressed to fit inside).īy turning the preload adjuster on the top of the fork and adding another 5mm of mechanical compression, the spring would then be exerting 15kg of force back out, meaning you would need to then apply more than 15kg of force in order to begin to compress it. That means that you would need to compress the spring by 10mm for it to fit inside your fork tube. The spring that you want to put inside the fork actually measures 330mm. It is a measurement of how much the spring is mechanically compressed in both the forks and shock when they are fully extended.Īs an example, let’s assume you have a front fork out of the motorcycle, and inside that fork you have a space for a spring that measures 320mm. The second option you have to change the spring’s characteristics is to alter the amount of preload that is placed on the spring. Likewise if you apply 10kg of force, it will compress by 10mm. The first is change it for a different spring with a different rate.Ī spring’s rate is the 1kg/mm figure we spoke about before, and how if you apply 1kg of force to the top of the spring it will compress 1mm.

In order to change the characteristics of the spring so that it better deals with bumps with a rider on board you have two options. If you remember in part 1 we spoke about springs and the role they play.Ī spring’s job (both front and rear) is to support the bike’s weight and allow the wheels to move over bumps while the bike remains in the same position relative to the road. In this part we are specifically going to be talking about preload, what it does, and why we would adjust it.Īfter we have covered all of that, in part 4 we will be going more into using preload to set rider sag.īut first, a quick recap… A Quick Recap on Springs

Setting pre load on softail shocks