Real world benefits of the slipper assist clutch

[Ulvetanna_imp]

The principle purpose of a slipper clutch is to reduce engine braking and increase rear tire control, especially if that engine braking is done abruptly and while heavily applying the front brake.

An easier pull is a side benefit.

Canyon running with my Sportster 1200 Sport would chirp the rear tire when I got lazy (not lightly blipping the throttle) on downshifting before a turn.

A slipper clutch would reduce that, but I've not had that issue with the 2014 CB1100. Nevada does not have the canyons that I enjoyed in SoCal, but Deer Creek Road (NV highway 158 in the Spring Mountains) is a smooth run on the CB1100.

Think of a slipper clutch as partially pulling the clutch lever when abruptly backing off the throttle.

In the broadest sense, yes.

But in the specific technical aspects of performance, engine braking is something that is determined by the tuning of the ECU through fueling adjustments.

Motorcycles today, especially high-performance racing engines, can be very precisely tuned for a variety of engine braking performance parameters.

For example, a WSBK bike can be tuned to increase or reduce engine braking for every turn on the racetrack. And that braking is adjusted automatically in real time by GPS location provided by satellite tracking.

Nicky Hayden crashed once because the GPS signal failed at a critical moment and his bike didn't have the engine braking he expected.

I just bring this up because it's an important point; engine braking can only occur if the engine is actually connected to the drivetrain.

A slipper clutch disconnects the engine and drivetrain until equilibrium is restored. Experienced riders proficient at shifting will likely never have the slip feature activate. If it does activate, even for a really bad shift, it'll only be for a few milliseconds, just long enough for the RPMs to again match up.

But as the post above indicates, the slip feature can partially disengage, provide some engine braking while still preventing serious rear skid.

But to be clear, the slip feature is like an invisible hand on the clutch; its purpose is the pull in the clutch a bit if you don't.

The principle purpose of a slipper clutch is to reduce engine braking and increase rear tire control, especially if that engine braking is done abruptly and while heavily applying the front brake.

An easier pull is a side benefit.

Canyon running with my Sportster 1200 Sport would chirp the rear tire when I got lazy (not lightly blipping the throttle) on downshifting before a turn.

A slipper clutch would reduce that, but I've not had that issue with the 2014 CB1100. Nevada does not have the canyons that I enjoyed in SoCal, but Deer Creek Road (NV highway 158 in the Spring Mountains) is a smooth run on the CB1100.

Think of a slipper clutch as partially pulling the clutch lever when abruptly backing off the throttle.

That is not the case, as Henning explains in the video.

"The whole idea behind a slipper clutch is that it prevents engine over rev and rear-wheel chatter, and helps keep the rear suspension working properly during hard engine braking caused by aggressive downshifts."

A slipper clutch will never, ever activate if the throttle is merely backed off. The deceleration force is nowhere near sufficient enough to separate the clutch plates. This would be a serious control issue because the clutch would suddenly re-engage if the throttle was applied, leading to a lurch. Its design function is to limit rear skidding during a bad, mismatched downshift only.

Henning misrepresents the function of these clutches when he says "no rev-matching required". A slip-n-grip clutch by no means can seamlessly match the revs for a rider in a transparent way. It doesn't remove the responsibility for riding well from the rider. You will darn well know when the clutch is being released by that "invisible hand" and it functions more like a light switch. Certainly, the slip-n-grip is nothing like a seamless, "no-brainer" kind of feature. It's like a crude version of ABS, it'll pull in the clutch for you if you screw up. It's not an "intelligent" feature, it's mechanical, and subject to very significant hysteresis and is not anything like "predictable".

Compare with intelligent ABS systems, which can seem "seamless" and transparent. Not the same thing at all.

I emphasize this point because, just as with ABS, if a rider thinks he or she can get away with not learning to shift, and the the slip-n-grip is just gonna save his/her bacon, they're gonna be very shocked and appalled when they crash because they think the system will prevent all possible losses of control due to poor downshifting technique. Think about what happens if you suddenly pull in the clutch just after chopping the throttle in a turn.

You lose engine braking and will run wide. A huge botch in a downshift will result in just this kind of reaction from a slip-n-grip clutch until it stabilizes.