63 Tiger Cub - Clutch

measlyincompetentUrban and Civil

Nov 29, 2013 (4 years and 7 months ago)


63 Tiger Cub


Will, Adam, Robert, and Jack

What is a clutch?

A clutch is a device used in machines to
transmit power from the engine to the

It can be engaged to allow the engine and
transmission to spin at the same speed or
disengaged to allow them to spin at different
speeds (thus allowing the rider to shift gears)

Wet vs. dry clutch?

Why do we need a clutch?

The clutch allows for a smoother shift from
gear to gear

Without a clutch the transmission would wear
down over time

Without a clutch, the only way to stop the
wheels from spinning would be to turn off the
engine (because otherwise whenever the
engine spins the wheels would too)

Clutch Parts

Clutch Parts

Backing Plate


plate, rebound rubber, drive rubber, spider, lock
washer, centre, centre driving cup, backing plate pin, sprocket
bearing ball, sprocket bearing ring

Sprocket and Housing

Double sprockets

Driven Plates


Lugs on inside

Engage with the

Driving Plates

Pads = cork

Lugs on outside

Engage with the

Pressure Plate

Presses plates together to engage clutch

Pushed up by clutch operating rod to
disengage clutch and allow rider to shift

Spring Cups

Pressure Springs

Press on pressure plate to engage clutch

Pressure Spring Nuts

Sprocket and Primary Chain

Why double chain?


double chain is more
durable, single chain
caused the sprockets
to wear down/break

Clutch Lever

Clutch Cable

Clutch Operating Rod

How It Works

When the clutch is engaged, the driven and
driving plates are pressed together by the
pressure plate and springs and spin at the
same speed

When the clutch lever is pulled, the clutch
operating rod pushes up on the pressure
plate, disengaging the clutch and allowing the
engine and transmission to spin at different
speeds, thus allowing the rider to shift gears


Why multiple plates?

Having multiple plates increases the friction,
thus reducing the slippage

The greater the friction, the greater the
torque that the clutch can handle without

How much force is applied by the

Gear ratio: 19/48

Length of spring: 1.53 in. = .1275 ft.

Length of spring after 20 lbs. applied = 1.324
in. = .1103 ft.

# of surfaces touching = 7

Coefficient of friction = 0.8 (cork on steel)

Diameter of clutch = 5.33 in. = .444 ft.

Clutch slips @ 50

How much force is applied by the

F =


F =


T =


Given a torque, we found compression in the

If we assume a certain amount of compression
in the spring, we can find any