Motorcycle Fork Rebound Top Out & Balance Springs

When your motorbike goes over a jump the front fork legs quickly extend to full length in the air - they reach the end of the rebound stroke & "topout". To stop those sudden jolting forces from damaging internals, some suspension manufacturers use rubber bumpstops, but most use one of these top out coil springs.

Oil damped forks only need short coils for the bumper, but lightweight modern air forks use a single, longer, thin wire compression spring because it does another job - although pneumatic pressure acts as the main "spring" - they still use one of these old fashioned steel spiral tubes as a "balance" spring.

Tuning balance spring performance is just like the old oils & coils - see our spring selection article info - stiffer rates & higher gas pressures for a heavier rider, softer rates & lower levels for lighter riders.

The "spring rate" you get using air alone is very progressive; imagine your fork is halfway through the stroke, there's now half the gas volume, and therefore double the pressure. At three quarters travel, it doubles again. Near the end of the stroke, you've got really firm resistance - good to stop bottoming out. But at the other end of the scale - a rider just sits on the seat & the initial rate is so soft the suspension looses most of its travel! To make the response more linear & predictable a balance spring firms up the starting force.

Reb topout springs can be replaced to adjust for tuning changes & racer weight - but to make sure you can tune your air fork equipped bike in the pits, please see our Air Fork Hand Pumps, Gauges & Adaptors.
But what if you're sick of the constant pump-up and air leaks out of short lived seals? What if ultra light weight exotic racing suspension isn't a big priority and you want something super predictable & reliable? Air forks just don't suit some people. If you want to keep that fancy new engine & chassis, but with comfy old proven damping, we have air to spring fork conversion kits.