What is fork stiction?

What is fork stiction?

What is fork stiction?

Stiction: an abbreviation of “static friction” - the friction between stationary surfaces at rest, which resists them beginning to slide over one another.
Friction: the resistance that one surface encounters when sliding over another. Generally speaking with suspension this refers to “dynamic friction”, ie the frictional force while already in motion.

Higher stiction and friction is prevalent with any air sprung suspension, because they simply have more sliding seals. With as many as 6 sliding seals present in air sprung fork designs, more force is required to overcome each seal’s static friction to get the fork moving.

Air sprung fork - stiction comes from many seals that make up air spring + dust wiper seals + damper + bushings.
Coil sprung fork - stiction only comes from dust wiper seals + damper + bushings.

You wouldn’t think that it would be enough to notice, but fork stiction massively affects small-bump sensitivity and is commonly the leading cause of ‘harshness’ in a fork.

Servicing your fork regularly is absolutely necessary to keep stiction to a minimum. When it comes to friction, coil sprung forks offer the ultimate small-bump sensitivity and plushness.

How to improve small-bump sensitivity:

  1. Service your suspension. It goes without saying that well-greased seals make for a smoother, slipperier fork. Over time, seal wear, contamination and lack of lubrication contributes to stiction - which is why your fork goes from feeling ‘sticky’ to feeling amazing after a service.

  2. You can improve your small-bump sensitivity with a Luftkappe, or to a larger effect, the Secus. They reduce the total force required to initiate the travel by significantly altering the spring curve. 

  3. You can convert to a coil spring system with the Smashpot and eliminate the air spring seal friction altogether.

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