Suspension Setup: Coil spring and optimal sag

Coil suspensions are suspensions with coil springs: helicoidal springs made of metal.

Coil springs have a specific spring rate each, the right one with the right stiffness must be chosen in relation to your weight, bike and practice.

Remember to take into account your gear's weight, like helmet, clothes, shoes and backpack.

Like with air spring, stiffness must be adjusted to achieve the right sag:

• Stiffness of the spring describes the ratio between a force acting on the spring and its deflection
• Sag is the distance your suspension compresses under your weight and gear

Stiffness is how elastic is a suspension when you apply a certain force (or weight) to it Stiffness directly impacts riding dynamics and indirectly affects all other adjustment options. Spring stiffness allows you to adjust the sag, which is crucial for riding dynamics.

Optimal sag enables the suspension to work efficiently in both compression and rebound, making sure your tires stay in contact with the ground when there are holes on the trail. Depending on the use and available travel, riders typically choose a sag between 23 and 33 percent. Generally, the more travel you have, the higher the sag values (DH and bike park riders will often target 28%).

For full-suspension bikes, ensure that the sag of the fork and shock do not differ too much. Otherwise, the bike’s handling might become too front- or rear-biased.

Coil spring rates can not be adjusted except if you use a spring meant to have different spring rates, like the Sprindex. To some extent, you can also pre-load the spring: coil springs can be pre-loaded, but it is not the same as a stiffer spring. Excessive pre-load can negatively affect the suspension’s response (topping-out), so we advise against using pre-load to adjust spring stiffness.