For an appropriate reproduction and precise chassis measurement and alignment
a vehicle measuring place must meet certain standards.
It is very important to have a plane level. The points where the wheels of the
vehicle are standing must be on the same level to each other. This is usually
checked with an optical leveling instrument, whereby the admissible difference
in height between left to right is max.1 mm, between front and rear and diagonally
may affect a max. of 2 mm.
For the highly precise chassis measurement at most modern multi-wishbone front axles, as MGF and other like e.g. BMW E36 or Audi A8 is only half of the differences in height stated above admissible!
With measuring lifting platforms it is to be noted additionally that the max.
admissible differences in height must be guaranteed in lowered position (for
initially and output of the measurement) and also in the raised working position
(for the alignment works).
Independently of a stage or pit measuring place the rotating and sliding supports
must be fixed by bolts or in retaining hollows, so that slipping away can be
avoided surely when driving the vehicle up or driving off.
During the chassis measurement the front and rear wheels should be as good
as possible centered on the rotating and sliding supports. All wheel suspensions
must remain free and free of spannings during the steering routines and alignement
works. So it is necessary that the rotating and sliding supports must be transferred
and adjusted to the respective wheel bases and track widths depending on the
vehicle that should be be measured .
At
the measuring place the road-contact areas must be set on same level by using
rotating and sliding supports to avoid measuring errors in camber, caster and
king pin angle.