Geely EC718, EC718RV, EC715, EC715RV. Manual part — 282

FE04-1011b

Parallel

transposition,

Diagonal

transportation

refer

to

1.4.2.5

Tire Rotation Description

Transposition Method.

Suspension System

Wheels and Tires

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4.4.3 System Working Principle
4.4.3.1 Wheel Alignment

Driver turning the steering wheel turn the vehicle to the desired
direction. However, if driving on the straight road, driver must
adjust the steering wheel from time to time in order to maintain
the vehicle straight-line driving, or turning at a corner, driver
makes a lot of effort, the driver will be under physical and
mental stress. To address this problem and to prevent
premature tire wear, according to certain requirements, wheels
are installed on a vehicle body (or chassis) at a certain angle.
These angles are called as "Wheel Alignment". It is a
comprehensive term referring to the front and rear axles,
wheels, steering components and suspension components
relative angles.

Correct wheel alignment makes the steering easy. On the
straight road, the driver only needs minor adjust to the steering
wheel to keep the vehicle move straight ahead, and only a little
effort to turn the vehicle. In other words, if various angles
constitutes the "wheel alignment" are adjusted correctly, the
turning will be easy. But even if one of them is adjusted
improperly, it may have the following problems: steering
problems; poor steering stability; poor steering wheel return;
reduced tires life.

Vehicle positioning angles include: front toe, camber, caster,
kingpin inclination angle, steering angle, tolerance angle,
forward angle, grinding tire radius. These angles and size
depend on the vehicles suspension systems, drive system
(Front-engine front-wheel drive or front-engine rear-wheel
drive, two-wheel drive or four-wheel drive), and the steering
system (manual or power steering shift). Adjusting these
elements will optimize the driving performance and steering
stability and prolong the service life of components.
Maintenance is usually recommended only for front toe
adjustment.

1. Front Toe

Front

Positive Front Toe
(Wheel Inward)

Rear

Zero Front Toe
(Wheel Parallel)

Front

Rear

Negative Front Toe
(Wheel Outward)

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Front toe is used to measure wheel rotation, or deviation from
the vehicle centerline. Another way to understand the front toe
is that two front wheels distance relative to the same vehicle
rear wheels distance. If all the wheels are completely parallel,
then these two measurements should be equal and the front
toe should be zero. If the front wheels tilt inward, the front toe
is positive. When the front wheels tilt outward, the front toe is
negative. Positive and the negative front toes are usually
referred to as the front wheel toe-in and front wheel toe-out.

Front toe function is to compensate for tire drag due to camber
and road surface resistance caused the inward or outward
rolling trend to keep the vehicle straight ahead.

2. Camber

Positive Camber

Vertical
Reference Line

Positive
Camber

Zero
Camber

Concave

Negative Camber

Vertical Reference Line

Convex

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Wheels and Tires

Suspension System

Camber is the vertical reference line of tires relative angle,
when a wheel is tilted outward at the top, the camber is positive.
When a wheel is tilted inward at the top, the camber is negative.
Camber settings can affect the vehicle direction control and tire
wear.

A variety of suspension and steering devices are designed to
keep the wheels perpendicular to the ground and move along
the straight road to minimize the tire tread wear and deliver the
traction, when starting the vehicle.

Improper camber settings will cause excessive tire wear or
uneven wear. Excessive positive camber will cause the outer
tire tread wear, when the load is higher at the outer tread side,
it will cause such uneven wear.

Excessive negative camber will cause the inner tire tread wear,
when the load is higher at the inner tread side, it will cause
uneven wear.

3. Caster

Front

Caster

Caster Offset

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Caster is the kingpin axis forward or backward tilt angle. Caster
is observed from the side when measure the angle between
the steering axis and the vertical line.

Backward tilt from the vertical line, is called as positive caster.
Forward tilt is called the negative caster. The steering axis
center line intersects with the ground, tire contacts the road
surface at a central point. The distance between these two
points is called the caster. Caster can provide straight road
driving stability: if the vehicle has a positive caster, when
turning, the left journal will have a tendency to move downward.
(This is due to the journal rotation along the tilted axis.).
However, because the journal is fixed to the wheel assembly,
besides the ground prevents it from moving down, the journal
will not actually move down, the left steering knuckle will be
forced to move up and down. This allows the body to rise

slightly. After turning, the steering wheel is release, the raised
body weight will force the steering knuckle move down, and
make the journal back to the original straight ahead position.

Suspension System

Wheels and Tires

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4.4.4 Diagnostic Information and Procedures
4.4.4.1 Diagnosis Description

Refer to

4.4.2

Description and Operation

get familiar with the system functions and operation before start system diagnostics, so that

it will help to determine the correct diagnostic steps, more importantly, it will also help to determine whether the customer described
situation is normal.

4.4.4.2 Visual Inspection

1. Check installed after market equipment that may affect the wheels and tires.

2. Check the easy to access system components to identify whether there is a damage or a potential malfunction.

3. Check the existence of the following conditions:

A. Obvious tire and wheel run out.

B. Apparent drive axle bounce.

C. Incorrect tire pressure.

D. Incorrect vehicle front end height.

E. Wheel bent or damage.

F. Debris on the tires or wheels.

G. Abnormal or excessive tire wear.

H. Tire defects include tire deformation caused by collision, tread separation or muster - slight tire sidewalls indentation is normal

and does not affect the driving ability.

4.4.4.3 Initial Inspection Before Tire Positioning

Note

Before the tire positioning, carry out the following inspection steps, otherwise, it may lead to incorrect positioning and
other fault.

Step 1

Check whether the tire inflation pressure is abnormal and the tire wear is abnormal?

Yes

Adjust the tire pressure to the specified value.
If necessary, replace the tire.

No

Step 2

Check whether the wheel bearings is loose?

Yes

Check whether the wheel bearing is loose. If
necessary, replace the wheel bearing. Refer
to

4.2.7.9

Front Wheel Hub Replacement

No

Step 3

Check whether the lower control arm ball joint and steering tie rod ball joint is loose?

Yes

Tighten the nuts. if necessary, replace the
lower control arm ball joint and steering tie rod
ball joint.

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Wheels and Tires

Suspension System