Slipper clutch vs. Center differential, explained! (RC Basics #2)

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Ever wondered what a slipper clutch does and how it's different than a center differential? In this video I explain these two options, and when you would want to use one or the other.

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[jubuttib]

6:48 Best way to think about it, an (ideal) open differential will always have the same amount of torque going to both axles, always being a 50:50 torque distribution. If e.g. the fronts can only take 10 Nm of torque before slipping, then the rear will also only get 10 Nm of torque, any extra you try to send will just go to spinning the wheels faster (increasing their rotational energy) rather than pushing the car forward.

Any kind of locking effect will allow the side with more grip to receive extra torque vs. the side with less grip via the slipping. With RC diffs using varying weights of fluids, it's most similar to a viscous differential in cars, the axle that slips kinda tries to drag the non-slipping axle up to its speed, or conversely the axle with more grip is trying to hold the slipping axle back.

The amount of extra torque transferred to the non-slipping axle should* be a function of the "weight" rating of the fluid and the RPM difference between the axles, i.e. with a heavier fluid and higher and higher RPM difference the higher grip axle should receive more and more extra torque. With something like a 20 million weight fluid, where you can barely get the diff to rotate at all, you can get nearly 100:0 torque distribution when doing a wheelie.

*It is in traditional viscous diffs with plate stacks, but I haven't extensively studied the effect in RC diffs, nor the heat response with added slip.

[DOFIXERR]

The more I'm getting into RC, the more I'm using your videos as a resource! Great vid my man. Having issues with the slipper on my Outcast 4S and had to research the basic understanding of how that works. 👍

[falcondragonslayer]

My brother recently replaced the slipper clutch in his Slash with a center diff. A slipper clutch works well for a racer or on-road car, but it doesn’t work that great for bashing or general joining around off-road. His Slash handles much better with the center differential than it ever did with the slipper clutch. An extra plus is the steel spur gear. You can’t have a metal spur gear on most slipper clutches, because there’s too much heat generated by the friction. Therefore, you need to use a plastic spur gear, which strips teeth extremely easily in something like a Slash. My brother’s Slash is 3 months old and he’s stripped 4 of the plastic spur gears in that time.

[NeoIsrafil]

If you jump, slipper is so helpful! When the tires stop because you suddenly hit the ground whole you're gassing it she'll save your gearing from stripping as well as the other soft parts.

[enricomiceli]

Remeber the most important thing, a slipper cluch it consjmes itself, it is going to go bad over time, a well kept diff (obviously if not abuse or used costantly to race and put under lot of stress) may last very long and every part may be swapped to repair

[subietech]

My Kraton 6s has 1 mil in the center diff and feels great

[wungee]

I always look at it this way.

Slipper/center spool for low-traction surfaces (dirt, clay)
Center diff for high-traction surfaces (pavement, carpet)

Locked slipper/spool is basically full-time 4wd. Center differential is AWD. AWD is fantastic when the traction is good, but not so much when it isn't. Full-time 4WD is fantastic when the traction is low, but will bind up the drivetrain when traction is high.

This is why in full-scale vehicles like the Jeep Wrangler that have full-time 4wd and no center differential, when you're driving on the road, your 4wd is disengaged. You only engage the 4wd when traction is low. But in a vehicle like a modern crossover SUV or Subaru, AWD is active all the time and rarely is there an option to lock the center diff to create a full-time 4wd drivetrain.

Some newer vehicles are starting to include this feature, like the new Landrover Defender. It can lock it's center diff which changes it from an AWD vehicle to a 4wd vehicle.

If you're running your buggy on carpet, go center diff. If you're running your buggy on clay or dirt, run the slipper.

[dcrook]

One of the best technical descriptive RC vids I've seen in years. 👍

How about "Cush Drives" in Traxxas RCs and XMAXX?

[nithishj]

i just love your content man. you got a fan from india...

[mulberry]

Great video buddy, because I need to adjust my slipper to save my wheel hex. my wheel hex is getting rounded off! Nylon wheels!

[scotnoco]

Glad I found this video! Fantastic explanation on both. really helpful thank you!

[kennethjeffries]

For me on my 4wd mod buggy outdoor its a center diff for sure with about 60k or less slippers are to touchy to drive on inconstant surfaces . Indoor on Turf or carpet gota say trying both the slipper clutch is much better smoother more forward drive /traction.

[AlxisAE]

Running a center diff in high grip is bad for your transmission, also on power the steering becomes dependant on how much the diff is moving so the amount of steering you have varies massively. You can also cook the center diff oil and cook the front tyres

[TurnII]

Can you review installing electronics and camber, toe setups on your B74! Nice video content on the B74, I just picked one up....

[yonicozac]

Nice comparison! But what about some words about dual slipper clutch systems like the Arrma 3s ones, where they can slip either side individually, so it acts more like a clutch

[RC_guy]

Sounds like this would be good for my 4x4 pede..I wanna chill on the wheelies

[erikdewane]

Thank you for taking the time to make this video! It was extremely helpful!

Your thumbnails look trashed: are you a mechanic?

[popwall]

Good video we need more stuff like this

[TrichbeeT]

can a center diff help prevent stripping pinion/ring gears when braking hard?

[ivanluhi]

Really nice explanation!
Thank you very much!