Measuring ride height
Here's another version of the picture, with the description for setting the factory ride height and the actual specs. The "V&L" line shows the A-body specs. Like the other picture it shows the measurement being taken at the bottom of the adjusting blade, which is on the round section, not out at the torsion bar adjusting bolt. So the angle of the blade being different for a different sized torsion bar shouldn't matter.
The other thing is, the factory ride height only provides the best suspension geometry if you use bias-ply tires. If you're using radial tires, the factory ride height specs will NOT give you the best geometry, camber curves, etc.
Just like the static alignment specifications are different for bias ply tires vs. radials, the camber curves, caster changes, etc, are different for radial tires. Think about it. Bias ply tires use specs that are almost opposite for what you want for radials- bias ply alignment specs use positive camber and negative caster. Radials use negative camber and positive caster for the best handling characteristics. The factory ride height takes that into account, it minimizes negative camber gain. Which is what you want for bias ply tires. But it's exactly the opposite of what you want for radials, you WANT negative camber gain on an ideal radial tire camber curve, it will provide the best handling.
Now, you don't have to set your car up for the best handling, that's totally up to you. And most people set their ride height based on the best appearance (in their opinion anyway), not necessarily the best performance or suspension geometry. And that's true at both ends of the ride height spectrum.
But, the idea that using the factory ride height is "best" because that's what the engineers designed for is totally mistaken. The minute you put radials on your car instead of bias ply's the factory design and settings being best goes out the window, because that's not what they were designing for, and not what the factory specs are set for. If you run radials, using the factory specs for alignment and ride height will not give you the best performance.
Here's another version of the picture, with the description for setting the factory ride height and the actual specs. The "V&L" line shows the A-body specs. Like the other picture it shows the measurement being taken at the bottom of the adjusting blade, which is on the round section, not out at the torsion bar adjusting bolt. So the angle of the blade being different for a different sized torsion bar shouldn't matter.
The other thing is, the factory ride height only provides the best suspension geometry if you use bias-ply tires. If you're using radial tires, the factory ride height specs will NOT give you the best geometry, camber curves, etc.
Just like the static alignment specifications are different for bias ply tires vs. radials, the camber curves, caster changes, etc, are different for radial tires. Think about it. Bias ply tires use specs that are almost opposite for what you want for radials- bias ply alignment specs use positive camber and negative caster. Radials use negative camber and positive caster for the best handling characteristics. The factory ride height takes that into account, it minimizes negative camber gain. Which is what you want for bias ply tires. But it's exactly the opposite of what you want for radials, you WANT negative camber gain on an ideal radial tire camber curve, it will provide the best handling.
Now, you don't have to set your car up for the best handling, that's totally up to you. And most people set their ride height based on the best appearance (in their opinion anyway), not necessarily the best performance or suspension geometry. And that's true at both ends of the ride height spectrum.
But, the idea that using the factory ride height is "best" because that's what the engineers designed for is totally mistaken. The minute you put radials on your car instead of bias ply's the factory design and settings being best goes out the window, because that's not what they were designing for, and not what the factory specs are set for. If you run radials, using the factory specs for alignment and ride height will not give you the best performance.
