When installing an extended swingarm on your bike, you drastically alter the leverage ratio and load on your rear shock. In order to maintain the correct suspension action, a new spring is mandatory. At Trac we have a complete selection of springs for almost all sportbikes. For street bikes, a stiffer spring is almost always necessary to compensate for the longer wheelbase of an extended arm, For the serious drag racer however, sometimes a softer spring will allow for the maximum performance.
