This works best for straight axle swapped (SAS) rigs. I have always had trouble and no confidence in tape measure alignments with larger aggressive lug tires. There are just too many variables. I saw this toe alignment tool and decided to give it a try as it was reasonably priced and should last forever.
www.ruffstuffspecialties.com
It didn't come with any instructions. It's solid and simple. Two laser cut and folded 1/8" plates. Ruff Stuff states they work for a wide range of bolt patterns, including 5x4.5 and 5x5.5.
Tools you will need for alignment:
-Alignment tools.
-2 identical measuring tapes.
-Level.
-2 jack stands.
-Floor jack.
-4 nuts and washers in your stud size (1/2x20).
-masking or similar tape.
Roughly measure the height of your axle with the tires still mounted. Remove front tires and use jack stands to set axle at the same height. Level the two lower wheel studs. Using the nuts and washers, bolt the alignment tool to the studs and get it level. Tighten the nuts. You can use the wheel nuts, but they are conical and allow the alignment tool to have a little wiggle. Repeat for other side. Lock the brakes. I used a piece of 2x4 wedged between the brake pedal and the driver seat. This will keep you from accidently turning a hub.
Use the notches in the alignment tool to set the measuring tapes in the same spots on both sides. I used masking tape to hold the end of the measuring tape in place. Pull the tapes straight with even pressure and measure to the edge of the fold of the alignment tool on both tapes. The front should be slightly less than the back measurement.
After I took this picture, I switched the wheel lug nuts to washers and nuts. It was much more solid.
Mine was a 1/4" toe in, which seems to be too much with this rig. Normal toe is 1/16-1/8" in at the front. I have rod end steering so I turned each tie rod end out 1/2 turn and checked again. Measured exactly 1/8" toe in, which is what I was shooting for. Got it back on its tires and torqued to spec.
I used a few zip ties to attach the nuts and washers to the tool, and secure the tools together for storage. The measuring tapes I bought for this have nifty magnets on them, which made it easy to attach to the tools.
Overall it was fairly simple and easy job. Took me about an hour total from tires on the ground to tires on the ground. I have much more confidence in this method than trying to measure tire edge to tire edge.

Toe Alignment Tool
Check out the deal on Toe Alignment Tool at RuffStuff Specialties

It didn't come with any instructions. It's solid and simple. Two laser cut and folded 1/8" plates. Ruff Stuff states they work for a wide range of bolt patterns, including 5x4.5 and 5x5.5.
Tools you will need for alignment:
-Alignment tools.
-2 identical measuring tapes.
-Level.
-2 jack stands.
-Floor jack.
-4 nuts and washers in your stud size (1/2x20).
-masking or similar tape.
Roughly measure the height of your axle with the tires still mounted. Remove front tires and use jack stands to set axle at the same height. Level the two lower wheel studs. Using the nuts and washers, bolt the alignment tool to the studs and get it level. Tighten the nuts. You can use the wheel nuts, but they are conical and allow the alignment tool to have a little wiggle. Repeat for other side. Lock the brakes. I used a piece of 2x4 wedged between the brake pedal and the driver seat. This will keep you from accidently turning a hub.
Use the notches in the alignment tool to set the measuring tapes in the same spots on both sides. I used masking tape to hold the end of the measuring tape in place. Pull the tapes straight with even pressure and measure to the edge of the fold of the alignment tool on both tapes. The front should be slightly less than the back measurement.
After I took this picture, I switched the wheel lug nuts to washers and nuts. It was much more solid.
Mine was a 1/4" toe in, which seems to be too much with this rig. Normal toe is 1/16-1/8" in at the front. I have rod end steering so I turned each tie rod end out 1/2 turn and checked again. Measured exactly 1/8" toe in, which is what I was shooting for. Got it back on its tires and torqued to spec.
I used a few zip ties to attach the nuts and washers to the tool, and secure the tools together for storage. The measuring tapes I bought for this have nifty magnets on them, which made it easy to attach to the tools.
Overall it was fairly simple and easy job. Took me about an hour total from tires on the ground to tires on the ground. I have much more confidence in this method than trying to measure tire edge to tire edge.