Laser Wheel Alignment: Chassis Mounted Vs Wheel Mounted

Laser Wheel Alignment
Systems are a modern
approach to wheel alignment.
Wheel alignment certainly is
one of the most significant
setup parameters for racing cars. You would ask why...
Because even things like
moment center location and
setup balance lose their
importance, compared to
wheel alignment. The alignment package has a
massive amount of influence
on the way that a race car
behaves and performs. One of the most common
questions asked is which is
best - wheel mounted or
chassis mounted lasers?
Answering such a query is not
easy: a more precise question would be which laser wheel
alignment method is better for
accuracy. Then, we would
have to say that the chassis
mounted laser is the right
answer. As to why it is so, please find below... The Wheel Mounted Laser The wheel mounted laser is
very much likely to give
mounting inaccuracies. Even if
the hub or spindle adapter is
flawless, it's still extremely
probable to have a burr on the hub or spindle face. Consider
the following scenario: a
simple piece of silicone 0.010"
thick left on the rear hub face
will throw the laser off by
0.332" by the time it reaches the leading edge of the front
tire. Moreover, once we mount
the laser to the wheel, that
wheel now becomes the
"master" reference point. In
order to apply this method with accuracy, you will have to
first check axle tube
straightness, and then test rear
end placement or wheel
alignment. This rule is valid for
all wheel mounted systems. On the other hand, what is also
true for wheel mounted lasers
is that the further you project
the laser, the more accuracy
you will gain. Still, in case that
your mounting surface and adapters are not absolutely
perfect, you will observe more
inaccuracy again.