Miata Mailing List: October 1998, Message #121

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It's very easy to do your own 4 wheel miata alignment and you don't need
lots of expensive tools.  All you need is a bubble level, some string, a
tape measure, and post-its.

An alignment consists of camber (front & rear), caster (front), and toe
(front & rear).  This procedure counts on the car being parked in a flat
location.

Camber is how much each tire differs from being vertical.  You can make a
camber gauge with a bubble level and post-its.  I have stock 14" alloys and
I measure referenced to the rim of the wheel which is 15" in diameter.  One
degree of camber is .261" over 15" (15*sin(1)).  Each .1 degree will be
another .026 inches.  So if you want 1 degree of negative camber, place a
post-it 15" above the bottom of the level, so that it extends .261" toward
the wheel.  When the level reads vertical, and the bottom of the level & the
post-it touch the wheel you're done.  The center caps of my wheels prevent
the level from contacting the wheel rim.  You can make spacers so your level
sits outside the obstruction - different sized spacers are even better than
using a post-it.

Practicalities: center the steering wheel, and after any adjustment, roll
the car back and forth a bit so there's no tire stress bending the
suspension, tightening the adjusters sometimes causes changes, so re-check.

Caster can't easily be measured, but you want all you can get.  So the aft
set of the front adjusters are set to push the A arm out as far as
possible - the front adjusters then tweak in the camber.

Toe is set using the method from last month's GRM.  You run a string around
the car 3 inches from the center of each wheel.  You tie the string to axle
stands or antifreeze bottles or...  Then you adjust the rear string anchors
equally so that the string width is the same both in front of and behind the
car.  Then for each wheel, measure how much closer the front of the tire is
to the string versus the rear of the tire.

This is a very easy, quick, and if you're at all careful accurate process.

Good luck
Mike Marzalek
mikem@sr.hp.com
'96 red aerodyne
Sonoma County, Ca.