How can I find out my alignment specifications if I built my street rod?
When street rods are built, they often use parts from various vehicles. Many times, this is the case with the steering system and alignment components. It is not uncommon to have incorrect, or in some cases, no alignment specifications for your street rod. Standard specifications may not be correct because the size, weight, and components of the vehicle may have been changed. The vehicle that I built had the frame and steering manufactured and assembled by one company, while the other parts of the vehicle were made by another company. I was also under the assumption that the frame shop set the alignment correctly before I purchased the frame. After driving the vehicle a couple thousand miles, I began to notice some front tire wear.
I decided to take the vehicle to a computerized front end alignment shop. After I told them I had no specifications, they suggested that they could get the alignment numbers close for my type of vehicle, its weight, and the associated parts. The two photos below show the (Before Measurements) before making any changes, and after making changes (Current Measurements). All measurements are read in degrees. They checked the camber, caster, and toe, on both the left and right front tires. Take a look at the Before Measurement to see how far they were out of specifications from the Current Measurements. Any numbers in RED mean that the measurements are out of specifications. Any numbers in GREEN mean they were within specifications. Also, each measurement has a range (easier to see on the Current Measurements photo).
Left Front Right Front
Camber 0.0 to -0.6 Camber -0.6 to 0.0
Caster 4.0 to 3.0 Caster 3.0 to 4.0
Toe -0.05 to 0.05 Toe 0.05 to -0.05
With these two diagrams it is easy to understand alignment and to observe potential alignment problems. For example, there was a positive camber rather than a negative camber. Caster was close to the specifications. However, toe was way out of specifications. After adjusting the toe, each measurement is now within the specification range shown. For example, total toe should be between -0.10 to 0.10 and the toe was set at 0.02 on the left side and 0.01 on the right side. The total toe was originally set at 0.41, and now it is set at 0.03.