Why Replace the Stock Front Forks
Almost all suspension feels good on smooth surfaces, but only some carries on feeling good over bumps.Designing damper pistons that flow fluid inside forks and shocks, and the shim stacks to control them, takes time and money. It also costs money to keep internal friction at bay. That's why a set of Ohlins superbike forks will cost so much more than OEM replacement. You're paying for the precision of the machining, the accuracy of the damper cartridge bore, and trick coatings on moving parts. That matters if you're trying to outbrake Valentino Rossi…
But sometimes you wonder if suspension feel is also about company philosophy. For many years in the '90s and early 2000s a good amount of motorcycle manufacturers, just didn't appear to think good high-speed control was particularly important. And maybe for some customers it isn't.
But say you're a motorcycle manufacturer who wants to build in good ride quality for today's crappy roads, but your accountant retains a grip on production costs. One cunning plan is to split the job of controlling compression and rebound between the two forks.
By convention, a normal fork leg handles damping in both directions, via separate rebound and compression pistons. So add two forks together and you have four expensive pistons in all, plus their awkward-to-assemble shim stacks.
Giving the job of compression to the left and rebound to the right means you can use the same forks but with just one piston in each leg. You don't need compression adjusters by the spindle either.
The catch is you're halving the working piston area. So each fork dive or extension is controlled by fluid through a single piston, rather than two sharing the load.
In isolation, motorcycles with these internals, like the original Triumph Tiger Sport, ride pretty well, even on the hideously bumpy roads. But it will never be as good as a motorcycle with damping pistons in both fork legs. So it's again compromise...
