Iveco Daily. Manual — part 272
50
WHEEL GEOMETRY
D
AILY
Base - May 2004
The king-pin camber angle (
β) is the angle formed by the axis
passing through the king-pin and the vertical to the ground,
looking at the vehicle from the front.
When the projection of the king-pin axis is near to the contact
point of the wheel with the ground (opposite tendency to the
wheel camber) the angle is positive, it is difficult to say that it
is impossible to have the king-pin camber angle negative.
The wheel camber angle (
α) and the king-pin camber angle (β)
enable wheel axis and the king-pin axis to come nearer as much
as possible to the contact centre of the tyre on the ground.
In this way, reduced tyre wear and lower steering torque are
obtained.
In order to have a good vehicle ground holding, a low
consumption of tyre and to enable the driving wheels to return
to straight running after steering, the front wheels are adjusted
at defined assembly angles:
- wheel camber angle;
- king-pin camber angle;
- caster angle;
- wheel toe-in.
These angles, accurately calculated, enable the correct balancing
of the forces created when the vehicle is moving, in the different
load conditions, tending to change the position of the wheels
on the ground.
Figure 1
Caster angle
Wheel camber angle
The camber angle (
α) is the angle formed by the axis passing
through the wheel centre line and the vertical to the ground,
looking at the vehicle from the front.
The camber angle is positive (A) when the upper part of the
wheel tends toward the outside; it is negative (B) when the
wheel upper part tend toward the inside.
32956
32957
32958
Figure 2
Figure 3
A
B
a
a
ß
The caster angle (
γ) is the angle formed by the king-pin axis with
the vertical to the ground, looking at the vehicle from one side.
If the projection formed by the king-pin axis falls in front of the
wheel contact point with the ground, in the direction of travel
of the vehicle, the caster angle is by convention positive (A); it
is negative (B) if it falls behind the wheel contact point with the
ground; it is equal to zero if it is perfectly vertical to the contact
point.
A
B
+
_
γ
γ
Camber angle
WHEEL GEOMETRY
51
D
AILY
DESCRIPTION
This angle makes it possible to keep the front wheels straight
when the vehicle is running straight and allows the wheels to
return spontaneously to running straight from the position
taken in the bend, as soon as the steering wheel is released by
the driver.
32359
32960
32961
Figure 4
Figure 5
Figure 6
The toe-in is negative if B is lower than A.
The toe-in is equal to zero if B is equal to A.
A
B
A
B
A
B
The wheel toe-in results from the difference between the
distances A and B (value expressed in mm) measured on the
horizontal axis of the rims, looking at the vehicle from the top.
In this way a light drive and a low tyre consumption is obtained.
The toe-in is positive if B is higher than A.
Wheel toe-in
52
WHEEL GEOMETRY
D
AILY
Base - May 2004
WHEEL GEOMETRY
53
D
AILY
WHEEL GEOMETRY
SPECIFICATIONS AND DATA
MODELS
29L - 35S
35
(1)
35
(2)
.40 - 45. - 50.
60C - 65C
WHEEL GEOMETRY
-
-
-
-
Wheel camber angle
(vehicle at static load) (
± 20’)
0
o
± 20’
0º 30’
± 20’
1º
± 20’
Wheel caster angle
(vehicle at static load)
3
o
± 20’
1º 35’
± 20’
2º 30’
± 20’
Wheel toe-in
(vehicle at static load)
mm
2
± 1
2.5
± 1
b
Steering angle:
a
b
Internal a
47
o
30’
± 30’
43º
37º 7’
External b
39
o
± 30’
36º 30’
45º 6’
a
Stub axle king-pin camber
α
13.38
°
7
°
(1) Front suspension with transverse leaf spring
(2) Front suspension with torsion bar
TIGHTENING TORQUES
PART
TORQUE
PART
Nm
kgm
Nut fixing king-pin to the side tie rod of the steering box
15
÷ 20
1.5
÷ 2
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