CEMB USA DWA 1000XLB - Manual (Page 25)

I 0645 26 GB
The runout phase allows correcting the wheel clamp mounting error.
This error is caused by imprecise positioning of the claws or by deformation of the rim or the wheel clamp
and is diffi cult to avoid. Even though there are wheel clamps on the market that are claimed to be "without
runout", there is actually no certainty that they suffi ciently reduce the error.
It is advisable to always execute runout.
The runout phase consists of executing various measurements at various wheel rotation angles.
A comparison of these values allows the software to correct the wheel clamp mounting error.
There are four runout methods: in two of these the wheels are turned by pushing the vehicle on the
ground, and in the other two by lifting the vehicle and turning the wheels by hand.
Each method is suitable for a certain condition; there is no best method for any one condition.
Method Execution speed Characteristics
180° on the
ground Fast If the conditions to execute this method are given, it is the
preferable one to use as it is fast and accurate. Since the vehicle
is moved on the ground, the suspension settlement is not altered
with respect to driving on the road and hence the measurements
are more realistic than the methods where the vehicle is lifted.
This method requires a fl at ground surface without steps (for
example, on sides of turn plates), little steering play and posi-
tioning of the steering lock to prevent the wheels from steering
when the vehicle moves (the instrument will signal an error if
this occurs). The surface must also be suffi ciently long to allow
the wheels to turn 180° and the vehicle must be light enough to
be easily moved.
90° on the
ground Fast Like the 180° runout on the ground, this method is fast and does not
alter the suspension settlement.
The requirements are identical, except that this method can also be
used with shorter surfaces (car lifts) as the vehicle needs to be pushed
only 90° to turn the wheels. An argument against this method is that
it is slightly less accurate than the 180° method and you are more
frequently asked to level the measuring heads because of the tighter
tolerance. It would be a second choice instead of the 180° runout on
the ground in case of short car lifts. It also requires that the ground or
lift be level.
180° lifted This method is not as
fast as on the ground If the conditions for the methods on the ground are not given,
the methods with the vehicle lifted must be used, among
which this one is preferable as it is slightly faster and more
accurate than the 3x90° method. It is as accurate as the 180°
runout on the ground but is slower because the vehicle must
be lifted and the wheels turned manually one at a time.
Since the vehicle is lifted the suspension settlement is altered
with respect to driving on the road and hence the measu-
rements are slightly less realistic than the methods on the
ground. Some car makers specify that the methods with the
vehicle lifted must not be used. To reduce this effect, the
suspension must be settled after lowering the vehicle.
3x90° lifted This method is not as
fast as on the ground Unlike the other three methods, it allows executing the
runout of one wheel without having fi tted the measuring
heads on the others.
This may come in handy because you can execute the runout
immediately after fi tting one measuring head without fi rst
having to fi t the others. It is obligatory to use this method
when the alignment sensors have been darkened by parts of
the lift or when using the mode with 2 measuring heads.
6 - RUNOUT