车轮和轮胎基本知识

Wheels

Demands of the wheels

∙Low weight,

∙Large inner diameter for large brake discs,

∙High form stability and elasticity,

∙Good heat dissipation (frictional heat),

∙Simple change of the wheels and tyres with tyre damages.

Assembly of a wheel

The wheel consists of the wheel and the wheel disc with central boring and bolt holes. Instead of the wheel disc, a wheel star is present or wheels or a wheel where steel spokes are connected with the hub.

The wheel is connected on the flange of the wheel hub which is pivoted pivot able with the steering knuckle adaptor end, with wheel nuts or wheel bolts. Other than that, the brake discs or the brake drums are mounted firm using bolts to the flange of the wheel hub.

With open lying bearings, the hub cover takes over the task of protecting the bearing and is a fat storage fort he fat reserves at the same time. Rims

There are rims which are fitted firm with the wheel disc and those which can be removed. Other than that, undivided rims are differed through rims (drop centre rims) and multiple part rims (Trilex), which find their use with Light and Heavy Goods Vehicles.

Drop base rims

For passenger vehicles, generally undivided drop centre rims are used. They are riveted or welded fest with the wheel disc or are casted or forged from alloy metals with the wheel disc as one piece.

The cross section of the rim can be symmetrical or unsymmetrical.

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1.Rim flange

2.Rim opening

3.Rim diameter

4.Drop centre rim

5.Rim bed seat

6.Hump

2

3

5

4

1

6

Hump rims

When using tubeless belted tyres, drop centre ring rims have to be used of which the rim shoulder, near to the drop centre rim, has a circulating round increment = Hump (H).

If the increment is not round and is flattened then one terms this as a

Flat-Hump (FH). Both of these should prevent that the tyre bulges when driving with higher speeds in curves that the rim shoulder is not pressed into the drop centre rim through the high lateral forces. With tubeless tyres, the air can escape quickly so that an accident could be the result.

Measurements and terms on the rims

These details are Normed. The rim terms are stamped in each wheel by the manufacturer. They consist principally from 2 dimensions, the rim opening (a) in inches and the rim diameter (D) in inches. Both dimensions are separated with an ”x” in drop centre rims.

Coded letters after the rim diameter give information about the type of rim. Press-in depth

This is the dimension from the middle of the rim to the inner contact surface of the wheel disc.

Through welding the rim and wheel disc, the press-in depth can be chosen. Therefore, the rim is determined for a certain chassis as the press-in depth relate direct with the kingpin offset.

Positive press-in depth

The inner contact surface, based on the middle of the rim, is displaced to the outer side of the rim.

Negative press-in depth

The inner contact surface is displaced to the inner side of the rim. Through using the rim with smaller positive or negative press-in depths, the spur width

of the vehicle can be widened.

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Example 6 ½ J x 13 H

6 ½ = Rim opening in Inches

J = Code letter for the measurements of the rim flange X = undivided drop centre rim

13= Rim diameter in inches

H = one Hump on the outer shoulder