Kiran N Poojary gave a technical seminar on slipper clutches to the Department of Mechanical Engineering at CMR Institute of Technology. The seminar discussed the components, working, advantages, and disadvantages of a slipper clutch. A slipper clutch is used in performance motorcycles to mitigate engine braking effects during deceleration by allowing some slippage between the engine and rear wheel. This helps prevent loss of traction and instability when downshifting rapidly.

1. Seminar by:
8th semester Mechanical
Kiran N Poojary - 1CR14ME037
Guided by:
Prof. Gopi S. M.Tech,(Ph. D)
Associate Professor
Dept. of Mechanical Engineering,
CMR Institute of Technology
Bangalore -560037
TECHNICAL SEMINAR
ON
Assist and Slipper clutch
Department of Mechanical Engineering
CMR Institute of Technology, Bengaluru 1

2. TABLE OF CONTENT
 Introduction to Slipper Clutch
 Components in a Slipper Clutch
 Working of a Slipper Clutch
 Case study of a Slipper Clutch
 Advantage & disadvantage of a Slipper Clutch
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3. Introduction to Slipper Clutch
A slipper clutch (back-torque limiter) is a specialized clutch with an integrated
freewheel mechanism, developed for performance oriented motorcycles to mitigate
the effects of engine braking when riders decelerate.
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4. Components in a Slipper Clutch
Slipper clutches are of various types and designs, but the most common and popular is
the Ramp Slipper Clutch. This works more or less on the principle of a freewheel.
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5. Slipper Clutch – How Does it Work?
• In normal operation, when the engine is trying to turn the rear wheel, the
flat engagement dogs push on each other, and the clutch drives the
motorcycle forward like a normal clutch operation.
• During massive deceleration or hard breaking the torque forces the ramps
together. To absorb engine braking force the ramps slide up on each other.
This action lifts the hub up from the base, in the direction of pressure plate.
It slides until the entire braking force is absorbed and then act like a normal
clutch.
• This mechanism is called spring loaded ball sliding up ramp aka Ramp
Slipper Clutch. The above process absorbs the engine braking force and
partially disengages the clutch from the engine.
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6. Case study of Slipper Clutch
Equipped Motorcycle
When you are riding at high speeds and suddenly you encounter a sharp corner – the
obvious reaction would be to slow down by applying the brakes and shifting in lower gear.
But what if you have lesser time and you want to shift 2-3 gears at a time? And when you do
this, you do it at the cost of damaging the gear box and putting your safety at risk which
arises due to engine braking force.
As a mechanism to reduce these issues, Slipper Clutch (also known as back torque limiter
clutch) was introduced. Slipper Clutch helps by allowing the clutch to partially slip until the
engine speed matches your own speed.
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7. How about normal clutches
In normal clutches, the engine braking force is transmitted to rear wheel via chain drive (or
shaft drive) which causes rear wheel to shake, jump or lose traction. This is the main
concept behind slipper clutch – to control rear wheel under hard braking and downshifting
that causes the rear wheel to lose traction. It is particularly helpful especially on higher
displacement bikes where the engine braking force is massive and may cause the
motorcycle to go out of control, resulting in a high-speed collision/accident!
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8. Slipper Clutch Advantages
• This slipper clutch ensures stability at corner entry as it will eliminate wheel hop
when downshifting and helps maintain rear wheel contact with the road surface.
• Slipper clutch reduces sudden forces on the inside of the transmission and hence,
reduces wear and tear on the transmission
• Reduces tyre wear
• It can prevent disastrous rear wheel lock up in case of engine seizure or
transmission failure.
• It also reduces work of suspension by absorbing engine braking force hence less
bumpy ride while cornering.
• The rider does not need to concentrate on clutch operation which allows him to
concentrate on other things such as body posture, braking etc while cornering.
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9. Slipper Clutch Disadvantages
• It’s mechanically complex.
• They are expensive compared to normal clutches.
• Sometimes you really need the engine braking force to slow down the
motorcycle.
• Slipper clutch can’t give desired results if not adjusted according to requirements.
• Sometimes engine braking is crucial, such as in steep downhill rides, and a slipper
clutch dilutes the engine braking effect, causing the rider to use the brake more
often
Practically there are no disadvantages of slipper clutch but hypothetically
there are a few as follows
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10. Conclusion
The Slipper clutch improves performance of the motorcycle by reducing the
stress on the gear box, rear wheel and also engine. It also reduces work of
suspension by absorbing engine braking force hence less bumpy ride while
cornering. Slipper clutch has a better lifespan compared to the conventional
clutch system. The main disadvantages of using this system is the cost and
complexity. If these disadvantages are overcome this system will be the most
preferred clutch system. In the near future automotive industry will implement
this technology.
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11. References
• https://patents.google.com/patent/US3072234
• Nilkanth G B and Patil S V 2015 Design and analysis of auto disengagement single
plate clutch in automatic transmission and its testing performance International
Engineering Research Journal 21366-1371
• MC Garage Video: How Motorcycle Slipper Clutches Work and Why They're
Awesome Motorcyclist. Retrieved 2018.
• Slipper Clutch; Working, Advantages & Disadvantages. bikeadvice.in.
Retrieved 2018.
• How Does A Slipper Clutch Work In Motorcycles?; zigwheels.com Retrieved 2018.
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