Slipper clutch a gripper clutch?

[salishmoto]

I'm not finding anything on whether the 21 NC slipper clutch is also a gripper clutch? The light lever pull seems to imply it would be since the springs are weaker. Does anyone here know for certain? Thanks.

 

[670cc]

For what it's worth, on powersports.honda.com, Honda calls it only a slipper clutch, and boasts of a 20% lighter pull. Below is the text from Honda's web site for the '21 NC.

Honda says:

"NEW SLIPPER CLUTCH​

On our manual-transmission NC750X, for 2021 we’ve added a new slipper clutch that helps eliminate wheel hop under downshifting, and which also lightens clutch-lever pull by 20 percent. Plus, we’ve given the transmission new gear ratios for first, second, and third, for more lively response on the road."

 

[salishmoto]

Thanks. I meant to post this in the 750 technical. It's ambiguous with these clutches as some slippers are only slippers and some are grippers. The NC doesn't make too much power, but the only reason to have lighter springs is if the gripper function is present since upon acceleration the gripper pulls the plates closer together without the need for stronger springs. Doubt anyone has taken one apart yet. Maybe I'll look up a replacement part and that may tell me. I'm just curious.

 

[670cc]

Thanks. I meant to post this in the 750 technical. It's ambiguous with these clutches as some slippers are only slippers and some are grippers. The NC doesn't make too much power, but the only reason to have lighter springs is if the gripper function is present since upon acceleration the gripper pulls the plates closer together without the need for stronger springs. Doubt anyone has taken one apart yet. Maybe I'll look up a replacement part and that may tell me. I'm just curious.

I understand your curiosity. However, my 2012 NC has nothing but a simple multiplate wet clutch. It works 100% fine and I never thought it needed any more complexity.

Thread has been moved to the NC750 Technical section.

 

[salishmoto]

Thanks again. Aside from any performance benefits, which I agree may be minimal, the main benefit is that this is going to be my wife's bike and the lighter clutch pull really helps her. She gets tired hands and forearms easily. Even on my 1400cc sport bikes with regular clutches I never had a problem popping my rear tire loosed on down shifts. Who is that careless?

 

[TNHoosier]

The NC seems to target newer riders. The slipper clutch will help maintain rear traction under less than optimal road conditions and downshifting techniques. It also helps to keep the front wheel on the ground when starting from a stop with inexperienced riders.

 

[TheIronWarrior]

Based on the claim of reduced pull, I'd assume it's a slip/assist clutch. From a mechanics POV, the same thing that makes it a slipper makes it an assist as long as the design of the clutch lets it "slip" backwards too. There's basically a 3rd piece of the clutch that's ramped, and any movement would either increase or release some clamping force on the clutch plates. It's possible to have it be slip only or assist only by limiting which direction the parts are allowed to slide, but a slip only clutch wouldn't lighten the pull.

FWIW, my Ninja 300 has a slip/assist clutch and I find it works very well. The pull is extremely light, but still gives good feedback when feathering. I've never had it "slip" on me, but based on how I feel the assist feature working, I imagine it would also work very well if needed. I assume where the output of the NC is similar to that of the Ninja 300, the feel would be similar. I know the (non-slip) clutch on my 2012 NC700 is much much stiffer than on the Ninja.

Thanks again. Aside from any performance benefits, which I agree may be minimal, the main benefit is that this is going to be my wife's bike and the lighter clutch pull really helps her. She gets tired hands and forearms easily. Even on my 1400cc sport bikes with regular clutches I never had a problem popping my rear tire loosed on down shifts. Who is that careless?

Slippers were initially designed for the track, where you want to keep pushing things as hard as you can and a slight foul-up could be a major problem. I think mostly from there, engineers decided they could use lighter clutch springs if they put these slip/assist clutches on street bikes. I'm assuming it's mostly the "assist" and not the "slip" that makes them desirable for street use, though the "slip" feature would still provide a bit of an extra safety net for those people who think that getting a 1400cc sportbike as soon as they get their license is a smart choice...

 

[salishmoto]

Ari has a good video from his days with motorcycle.com. In it he points out that a slipper can be only a slipper, based on how the cogs are shaped. He shows an example. In any case, no doubt for the majority of people on an NC the only thing they would care about is the easier clutch pull. My mechanical mind is interested in the gripper function because it would seem to extend clutch life. With a mechanical pressure forcing the plates together firmly instead of mere springs, it would stand to reason that they would be held more firmly and resist slippage as they wear. It's a clever idea. The slipping aspect is pretty useless to me otherwise since it wouldn't even lighten the pull.

I looked up a parts diagram on one of those OEM sites and the photo doesn't show enough detail to see the cogs that Ari shows in his video. And no one has videos up on ustube about the 21 clutch replacement yet. Purely a curiosity. Appreciate you all sharing your ideas.

 

[TheIronWarrior]

My mechanical mind is interested in the gripper function because it would seem to extend clutch life. With a mechanical pressure forcing the plates together firmly instead of mere springs, it would stand to reason that they would be held more firmly and resist slippage as they wear.

I doubt you'd see increased life for two reasons:
1) In general, the assist feature is coupled with lighter springs for a lighter lever pull. I would anticipate that any increased clamp force from the mechanical workings is offset by the loss in clamping from the weaker springs.
2) Clutches see minimal wear when fully engaged or disengaged, most of the wear comes during the "in between" phases where the plates are sliding against each other. As long as things are properly designed, you would have no more or less slippage under acceleration whether you had a conventional or an assist/slip clutch. What you do have, however, is a clutch that will slip rather than lock up the rear wheel under excessive engine braking. Any time the slipper clutch does it's slipper thing, you're accelerating the wear on the plates, though this scenario is likely uncommon enough that it's negligible.

From the above, we can conclude that an A/S clutch is likely to have either no impact on clutch wear, or even accelerate clutch wear. You would be right that spring+assist would increase the clamp force and allow for more wear before clutch slip under acceleration, however it would be no different (with the exception of lever pull) than having had stiffer springs, and as far as I know, any bike that has an A/S clutch reduces the clutch springs accordingly.