Miata Mailing List: October 1998, Message #626

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Fletch,

Thanks for your note - I just figured out how to measure caster - or at
least get it the same on both sides...

I do expect that there will be caster variation from side to side due to
manufacturing tolerances.  Caster is the angle of the wheel steering axis as
inclined fore & aft.  As you turn, the caster will cause a slight change in
the wheel's camber.  This is a second order affect.  You can check that the
caster is the same at both wheels by first setting the camber, then cranking
in full left lock and measuring the camber of the right front (the outside
tire does the brunt of the cornering work), then crank in full right lock
and measure the camber of the left front - they should match.  Remember to
rock the car before measuring.

Now I'm curious to see how much the camber changes at full lock.  Gotta find
out.

Thanks again
Mike Marzalek
mikem@sr.hp.com


Fletch wrote:

I know from when I've had my alignment done on a machine that the maximum
caster acheivable frome one side of the car to the other is vastly
different. (4.5 deg versus 3.5 deg) I'm not sure if this is because of
previous crash dammage, worn bushes, or just manufacturing tolerances.

The guys who have aligned my wheels in the past have elected to crank the
passenger side back to match the maximum acheivable on the drivers
side...

Thanks,

Fletch.