Performed an alignment this morning and thought I'd share my DIY alignment kit and method that I use to set toe-in on my TJ.
I was never happy with the "scribe a line", "bungee to the outside of the wheel",
or "measure from one tire seam or lug to another"
The kit contains:
2 - 48" Steel Square Tubes (marked at the center points and at tire diameter)
4 - Large Pony Clamps
2 - Small Pony Clamps
2 - Tape Measures
6 - 1/2"-20 Nuts with Washers
2 - Bullet Levels
1 - Place on jack stands close to ride height and remove front tires.
2 - Use nuts and washers to secure rotors to unit bearings. <-- IMPORTANT!!!
If you don't, you can't achieve any accuracy.
3 - Center steel tubes on the lower side of each rotor and clamp with large pony clamps.
4 - Use bullet levels to place bars into same horizontal plane.
5 - Run two tape measures from one set of steel tubes to the other at the marks representing the tire diameter, clamp one end of the tapes with small pony clamps making sure to not affect the tapes ability to record an outside measurement, and let the other end hang suspended above the ground.
6 - Compare the measurements of the two tapes. In my case, I've targeted the front to be 3/16" smaller than the rear for my 35's (toe-in). The actual measurement does not matter, just the difference between the front and back tapes.
Front = 57-10/16"
Rear = 57-13/16"
7 - To adjust, loosen the clamps on, and rotate the tie-rod until you reach your desired setting. You'll see the tapes slide on the tubes as the tie-rod is turned. I use the inside edge of the tubes for my measurements so that I'm not fooled by the curvature of the tape outside the tube.
8 - Once you're happy with the delta of the front and rear tapes, tighten the clamps on the tie-rod, keeping in mind the clamp positioning relative to any moving parts that may come into contact with them.
9 - Then, you can center the steering wheel by loosening the drag link clamps and rotating the link until your wheel is centered. Once it's centered to your liking, tighten the clamps on the drag link, keeping in mind the clamp positioning relative to any moving parts that may come into contact with them. You may need to repeat this step a couple of times after test driving the Jeep to get it just right.
Easy as pie...