HappyToe Measurement System

Are you still setting your front toe by eyeballing it? Happy Toe is for you! I set out to design an accurate toe measurement tool that is inexpensive and easy to use. Secondarily, I have always wanted to document my oval cars with an absolute measurement of the angle of each rear tire, and the Happy Toe System can do that too. Happy Toe is built for 10th scale buggy-based vehicles and similarly sized cars with 12mm hexes to mount wheels.

Happy Toe starts with the front measurement tool, which has a pair of wheel blocks and a matched set of rulers. It includes a couple of standard hair bands to gently hold the rulers in place, although these aren’t necessary unless you are making rear measurements. Unless making rear measurements, leave rear tires on your car and replace the front wheels with the two blocks. A flat smooth surface is ideal for accurate measurement. With the front tool in place, taking a measurement is simple: the difference on the rulers is the amount of toe in degrees, and that’s positive toe (wheels point out) if the front ruler is longer than the rear ruler. You’ll need to estimate fractions of a degree by eye.

Next, the thing that I believe only Happy Toe does. Happy Toe can measure the absolute angle of each rear axle relative to the car’s centerline. This measurement considers everything that can affect the axle angle: rear steer, C and D blocks, pills, staggered rear arms, and so forth. It provides a data point that can be reliably replicated on any other car. By measuring the angle of both rear axles, you can also calculate the rear toe of any car.

Using the rear measurement tool of Happy Toe is a bit more complex. Start by installing all four wheel blocks, then the two rulers between the front ones as described above, and hold the rulers in place with the provided hair bands or other elastic. Next, install the parallel bar, which runs parallel to the chassis centerline. Place rear ruler on top of the parallel bar and into the groove on the wide end of that piece. Install side bar by placing it under the chassis and over the parallel bar with the bar in the groove in the wide end over the parallel bar. Finally, adjust the parallel bar, side bar, and the angle plate until the straight edge of the angle plate runs along (or parallel to) the wheel block on the side being measured. Read the indicated angle.

Before shipping, I adjust the groove width on both bars of the rear measurement tool so that they are snug to the bars they ride on but move freely. The alignment and snugness of these grooves may be adjusted as required with a 2mm hex driver.