ANTI-DIVE front forks have been this mythical type of motorcycle technology, that both never seems to fully go away yet never makes it into mainstream bikes either.
The idea is fairly simple; remove some of the dive that occurs in heavy braking without preventing the suspension from absorbing bumps in the process. The thought is that without the weight transition from braking to turning and then accelerating, the bike can remain more level and stable throughout the corner.
With so many hit and miss examples of the perfect anti-dive solution over the years, you’d be forgiven we’d have seen them all already. Although glancing at these patent drawings from some of the boffins at Aprilia and it’s clear there is still fresh ground being broken in this little area of bike design.
How does the Aprilia anti-dive front fork work?
The new system uses a linkage that attaches to the fork stanchion and it attached to the caliper mounting plate which itself is designed so it can pivot a few degrees around the axle of the bike. As the brake is applied, the mounting plate tries to turn in the same direction as the front wheel. This turning force exerts itself through the linkage that attaches to the fork stanchion and effectively pushes the bike back into an upright position. Once the braking event is completed, a spring forces the caliper mounting plate back into its neutral position.
To help control the system and tune the amount of anti-dive, the rotating plate is locked into a grooved slot on an aluminium rocker. The chosen arc of the groove denotes when and by how much the forks will or won’t dive. This system means the anti-dive action will be progressive, working move in the initial and more ferocious part of the braking event, with the effect steadily tailing off as the forks compress more.
The system should work in such a way that in that first braking phase, normally the hardest, the forks won’t dive too steeply, but as more and more compression goes through the fork after then, the anti-dive effect will lessen. As it reduces the forks should then be better able to deal with bumps and undulations as the rider turns the bike into the corner.
The Aprilia system is trying to get around some of the issues other anti-dive systems have, in that the feel of a normal front end is lost and can become vague feeling.
Interestingly, the bike shown in the patent drawings is Aprilia’s RS-GP MotoGP machine. Had Coronavirus not stopped play, we might have already seen the system lining up on the MotoGP grid already!
