Section 12 Wheels - ZONGSHEN ZS125-86 Service Manual

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Table Of Contents

Table of Contents

The front and rear wheels are the running parts of the motorcycle, which support the mass of the whole

vehicle and ensures a reliable adhesion to the road when driving to prevent slipping. The wheels can

mitigate and absorb vibrations and shocks for road reasons. The front wheel together with the steering part

of the motorcycle determines the driving direction. The rear wheel is powered by the engine and drives the

motorcycle. The wheels are mainly composed of cover tires, inner tubes, aluminum wheels, wheel hubs,

bearings, bushings, oil seals, wheel axles and other components.

1. Structure and Working Principles of Wheels

[1.]Tires

Motorcycle tires are an important part of the running system. Tires contact with the road directly, bear

the mass of the whole vehicle, ease the driving vibrations and shocks by virtue of the elasticity, and ensure

the driving balance. Tires are of reliable adhesion. Tires include cover tires, inner tubes and liner bands.

Cover tire

The cover tire consists of the tread, carcass, buffer layer and bead. The cover tire treads directly

contact with the road. Various tread patterns enable the motorcycle to get the appropriate adhesive forces

in different pavements. The carcass should be of a certain strength, but not too thick for purpose of heat

dissipation. The bead is made of the cord fabric edges, the bead ring and the wrapper, so that the tire

is firmly fixed on the rim. If the circumference of the bead is too short, it is difficult to disassemble and

assemble the tire. Too long circumference may make it easy for the tire to jump out. The cord fabric layer

is the skeleton of the cover tire, and the cord fabrics of the cover tire intersect with each other and forms

a corner with the tire cross section (crown angle). The cord fabric lines in a radial tire are arranged in the

radial distribution direction. The crown angle is 0 °. The radial tire has merits such as reduced power

loss, fuel savings, and long life, etc.

Inner tube and liner band

The inner tube is made of rubber and has a circular shape. It is equipped with a cycle valve, through

which the pressure inside the tube can be adjusted. The inflatable pressure in the inner tube is the main

factor affecting the use of wheels and tires. The main indicator of the inner tube is the air tightness.

The liner band is an annular rubber band, which separates the inner tube from the rim, protects the air

tightness of the inner tube, and prevents the inner tube from being punctured by the sharp protrusions.

[2.]Wheel rim

The wheel rim is a skeleton that supports and secures the tire. The wheel rim may be a die-cast rim

and a spoke-type rim. Die-cast the wheel rim and wheel hub into a whole by use of aluminum alloy and

then machine it, consequently forming a die-cast rim. Such a rim is high in strength, simple in process

and easy in assembly, but it is of poor elasticity and cannot be adjusted. If deformed or damaged, the rim

should be replaced completely. The spoke-type rim is made by rolling steel strips. There are a number of

hole seats in the circumference of the rim. Each hole seat is fitted with a spoke and spoke nut. The other

end of a spoke is connected to the hub. Such a rim has a good impact resistance, is adjustable and easy

for maintenance. In this section, take the die-cast rim as an example.

[3.]Wheel hub

Wheel hubs of a motorcycle are divided into front wheel hub and rear wheel hub. Front and rear wheel

hubs are basically similar in structure, but as the rear wheel is a driving wheel, a power transmission

structure is added to the rear wheel. For the benefit of normal movement of wheel hubs, front and rear

wheel hubs are equipped with bearings, bushings, oil seals and wheel axles, etc.

2. Demolition and Maintenance of Wheels

Check the front tire