Car + Alignment DIY

So I decided to align my car over the weekend after tinkering with the suspension to find an annoying vibration at highway speeds+. In turn I threw out my from wheel tow. I was considering taking the car into a shop for one of those $40-50 alignments but thought I would give it a try.

I did some theory and trials (both on my car and my wife's car). I came up with an idea of using the center of the rim as a pivot point and using a string to create a parallel line between each side. I'll use ascii to describe :)

[ignore the '.' - blogger thought my multiple spaces were invalid]
Wheels: .....-----..............-----
Measure: ......|..................|
String: -------------------------

As the crude drawing shows I measured 70mm from the center of each rim (alloys so no hubcap to worry about). The down side is that if the front or rear has been shoved in/out this would mess things up badly, to check I measured the rear wheel (since it has no tow) on both ends of the rim and if they match then the line is parallel with the car. The most I can determine is if i was off by ~ .3mm which would be an error of about .004 deg. The only thing this can't do is camber/caster alignments but unless you hit a massive pothole or slam into a curb this typically wont be thrown off.

The alignment process is the somewhat painful part. Since lifting the wheel off the ground would invalidate the line I needed to adjust it without moving the car, cardboard and long arms for a low-clearance car! Oh an make sure to have the steering wheel straight first :) Do the same procedure as the back tires (measure along line the front and tail of the rim, not tire) and make the measurements equal. It took me a few tries because the steering arm rotated on me when re-tightening the nut. Also use a metal ruler and a level bubble otherwise you could be off by +- 1mm which could be ~.14 deg. (seems small but at highway speed will cause a drift!)

Take it for a test drive -- go on a highway and on a straight let go and wave to everyone! My car went straight as an arrow and had no wondering (tow-out) [helps not having a wind or slant]. I brought it back to the garage and checked it again to make sure things stayed in place (and to double check the setup) and things looked good. Saved $50 :)

[Blah legal stuff, only takes one fool to mess up your life... Note: You take full responsibility for your own safety and car, don't blame me for your screw-up!]