Given the expense of alignment on a professional rack, as well as the frequency with which it has to be done, I figured I would have a go at designing an alignment rig for my home garage.

Here's what it looks like - an aluminum extrusion frame at front and rear of car, with strings running front to rear.

   

I cut grooves into the extrusion to enforce the distance between strings be as close to identical as possible in the front and the rear. This makes the setup square.

   

The frame is then adjusted to make the string equidistant to the front and rear hubs, left to right, respectively.

   

You can read the toe directly off of this contraption that I designed, which is basically some rulers glued together and a 3D printed part to attach it to the wheel. The 3D printed part locates the cross-wheel beam (larger ruler) to be on the wheel's centerline, and also keeps the face of the cross-wheel beam perpendicular to the wheel face. The cross-wheel beam registers on the rim edge.

   

Here's another look at the 3D printed contraption:

   

To measure Caster, I used turn-plates and added a 3D printed pointer. It's difficult to get the angle reading without it.

   

To measure camber, I found some surprisingly-flat square stock and used these digital levels. At first, I used two in order to ensure the perpendicularity of the stock itself, with respect to gravity, before taking the camber measurement itself. The camber measurement doesnt seem to be very sensitive to the perpendicularity of the stock. The digital levels themselves have poor repeatability, and are kind of the wrong tool for the job, given they probably only need to acutally measure +/- 5 deg of range and have 180 deg of range. The Savage brand level has better resolution (.05 deg) than any of the small square carpentry ones (which all seem to be the same exact range and accuracy). Repeatability is where these suffer, though.

   


Here's the bill of materials:

Frame Extrusion
Savage Level
Turn Plates
String
Small squares used for toe measurement
Cross-wheel beam

3D Printed designs attached as well. Note the wheel attachment is designed to fit my wheels, which are Enkei PF01.

Enjoy!

Attached Files

  Alignment Tools.zip (Size: 571.04 KB / Downloads: 0)

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