The rear shock on the full suspension model can be easily adjusted with a Park BB tool, or even easier to use your hand to turn it. Minimizing the spring length will increase the preload on the rear suspension. While lengthening the shock will decrease the preload.
We recommend you use the full length of the shock to get the comfort of the suspension throughout the stroke. The full suspension model the the most comfortable bike we offer, it is an ideal frame for a small collapsible bike.