There is a cheap and easy way... from my build thread:
Originally Posted by Dominik
So last night i decided to build my own alignment tool.
It started with a design:
Which turned into a little DIY construction:
If anyone else is interested in doing their own alignments, this is what i used:
4x angle brackets (usually used for shelving)
6x 90cm lengths of 19x42mm pine (tested for straightness
2x 3m/10ft tape measures
2x small angle brackets to hold tape measures
1x plastic card (or sheet plastic or anything to put under the tape measures to calibrate/measure against)
Some screws to hold it all together
All available at bunnings for under $30 total.
Calibrate the twin tape measures so they both measure the same distance against the edge of an old BIC Camera points card
Now put it up against the car and see what my toe settings are!
(Disregard the temporary front bumper which is all but falling off, and the general dirtyness of the car!)
That's pretty well done! How accurate did you find your measurements against a laser alignment? Also would it be possible to work out the actual toe, or does all depend on how straight your wheels are facing? (I suck at maths )
Havent had a laser alignment but the tyre wear says i am doing ok (at my camber settings any toe results in very fast tyre wear).
This method does not measure thrust angle (if your front wheels are facing the same direction as the rears), but that can be measured with pieces of string.
The maths involved is as simple as take the measurement of the front tape measure and compare it to the rear one. If front is bigger than the rear you have toe out, the opposite means toe in. Then get under and adjust toe and remeasure.
Anyway, something i forgot to mention, is that with all their fancy laser alignment tools and computer read-outs accurate to 0.01mm; its all pointless since most cars have rubber bushings in the suspension that allow 2-3mm movement in the suspension settings (moreso when they are old and worn). Only exceptions to that are full blown race cars that have replaced every suspension bushing with pillow-ball arms (i have replaced most on my car)
When researching this alignment rig, i spoke to people who work at alignment shops, who said that they can spend an hour aligning a car perfectly; take it around the block and put it back on the hoist and it will be out by a few mm every time. Apparently Mercedes service centres actually put Sandbags in the car to simulate driver weight and put braces under the car to take up the free play in the rubber bushings; I can guarantee BobJane aint gonna do that for ya!
And last point; i had my car 'laser aligned' at a dodgy shop and when measuring on this rig i found it to be out by almost a cm. Laser aligners are only as accurate if they are properly calibrated!
My advice: Get it done properly ONCE by a reputable aligner, and then maintain it with DIY alignments!