Motorcycle Suspension Adjustments

At the end of the first day of the superbike round we had a little time to film another video. We asked Konstantin to tell us about racing suspension.

Fork

An upside-down fork has 3 adjustments: preload (the initial «zero» compression of the spring at rest), compression (the resistance that occurs when the fork compresses, that is, the speed at which it compresses) and rebound (the resistance that occurs when the fork returns to its zero position after compression, that is, the speed at which it extends).

Every fork has initial (zero) settings set by the manufacturer for a specific motorcycle. Spring rate matters a lot: it is also an adjustment, but not a quick one. To replace the spring you have to partially disassemble the fork leg. Professional mechanics do this very quickly (see the diaries) and have a dozen springs of different rates. Rivamoto motorcycles use a modified racing fork in which one leg handles compression and the other rebound. This makes the fork lighter, since each leg has only two adjustments. Adjustment also becomes simpler, since rebound and compression are set once each rather than twice. Reliability increases thanks to fewer components in each leg. Tests and the near-universal use of this fork in racing have shown that it gives better front wheel feel and works more effectively under acceleration and braking.

Rear shock

The rear shock has the same adjustments as the fork. The main feature of a racing shock is the convenience of its adjustments. On stock shocks you need a special wrench to change the preload, the nut is very awkward to reach, and rebound and compression are sometimes in hard-to-reach places. On a racing shock all adjustments are placed as conveniently as possible for mechanics, which allows settings to be changed instantly. Just like with the fork, spring length matters a lot!

Suspension is set up relative to the zero values during practice sessions and qualifying. For this the whole range of ride data is analyzed, with particular attention to data from the potentiometers (directly on the fork and shock), as well as from the front and rear brake sensors (suspension behavior under braking matters a lot) and the speed sensors (suspension behavior under acceleration).

In the diaries you can watch a report on spring changes and suspension setup in the Rivamoto pit box during practice and qualifying.