If you’re shopping for a motorcycle, you’ve probably seen the same phrase pop up again and again: “Slipper clutch.” It’s in reviews, in ads, and it probably doesn’t sound all that great — isn’t a slipping clutch a bad thing? It is, but a slipper clutch isn’t slipping in the way you’re thinking. It’s simpler than it sounds, and I’m here to make sure you get it.
A slipper clutch does slip, yes, but only in one direction. You generally think of your clutch as “slipping” when it allows the engine to spin faster than the gearbox — you get all the revs your right foot can ask for, but none of the associated speed. Slipper clutches, by contrast, do the opposite: They allow the transmission to spin faster than the engine. This means that dumping the clutch at low revs and high speed will never lock up your rear wheel, but instead allow the clutch to slip until your drivetrain’s speed matches that of your crankshaft.
Making things faster and easier
How a slipper clutch works is just a bit of clever engineering. Ramps in the clutch basket separate the pressure plates from each other when the rear end is moving faster than the engine, preventing the gearbox from spinning up the engine or getting caught up in its friction. It’s not a phenomenon you’ll really think about from the seat, but it can help you out when you flub a downshift — tech that goes unnoticed except when it’s saving your ass is the best kind of engineering out there.
Slipper clutches come from the racing world, where they help with the high-intensity shifting required for track work, but they’re now getting to be extremely common. Sportbikes have slipper clutches, but so do street bikes — even beginner bikes are increasingly getting slipper clutches, in order to be less exacting in their usage while new motorcyclists learn their way around a manual gearbox.