Ref.: MEL-WA(3D HCV) - OM Ver.1.7
21
5.10.
WHEEL RUNOUT
Fig. 16
RUNOUT
is one of the important factor which affects a good wheel alignment. Hence
Runout compensation is a critical parameter in wheel alignment.
Runout is the wobbling of wheel with respect to neutral axis ie., vertical axis of Camber
and the axis parallel to Geometric centre line in case of Toe. This wobbling affects the
Camber and Toe parameters. Runout exists even in new vehicles. But it will be more
in old vehicles due to wear and tear. Now let us see how Runout affects the Camber:
T
R
U
E
VER
T
IC
AL
1
0
'
(MI
N
IM
U
M)
3
0
'
(A
VER
AG
E
)
5
0
'
(MA
X
IM
U
M)
ROAD
Fig. 17
Assume that there is a wobbling of 10' to 50' in a wheel and Runout is 40' (max.
– min.
reading). This means, when the vehicle is in motion, the wheel will have a varying
Camber of 10' to 50' during every rotation. This is inevitable. Logically the average
point has to be taken as the real Camber (ie., 30' in this case).
If the specified Camber for a vehicle is 55', then adjustments must be made in the
shims / Cam mechanism suitably to affect a wobbling movement of 25' to achieve the
average Camber of 55' (ie., 30' + 25' = 55').
After the adjustment, Average Camber
= 55' (required)
Minimum Camber =
35‟
Maximum Camber =
75‟
T
R
U
E
VER
T
IC
AL
3
5
'
(MI
N
IM
U
M)
5
5
'
(A
VER
AG
E
)
7
5
'
(MA
X
IM
U
M)
ROAD
Fig. 18
