• With the vehicle on the ground, measure from center to center at the mounting points (bolts)on the shock. This will determine what is called static or ride height. Often times customers will call, with extended and collapsed lengths of current shocks on the car. I prefer ride height because this tells us where the suspension is working. What if, for example, the car has been lowered or raised by the previous owner. Now the current shock length could be the incorrect length causing bottoming or topping out of the shock. And you purchase the same length shock!
• NOTE- Vehicle should loaded as you would normally drive it, fuel etc. this may not seem that it would matter but on a lot of these vehicles we are dealing with a limited amount of travel. For instances a vehicle with very little fuel, no passenger and your tools removed could alter the ride height by 1/2" or more. Believe me, I have seen some hot rods with a lot of junk in the trunk!

After taking your ride height measurement start looking for any clearance problems.

• Take a very close look at all points at which the suspension could come in contact chassis, exhaust, body, fender wells, etc. Having 3" of shock travel won't do you any good if the center section hits the floor pan in 1"!
• Also check clearance at the spring hat on the top of the shock to the crossbar, keep in mind the shock angle can change as the suspension moves up and down.

• This is the reference angle from vertical An An angle of 20-25 degrees is generally acceptable, but the greater the angle spring rates and/or valving might need to altered as it puts more leverage on the shock & spring. Angle is not a bad thing because it will increase the amount of wheel travel to shock travel. How do you find the angle? An inexpensive angle finder can be purchased at most home improvement centers for around $10 and you can even tell the wife when she sees the receipt that is for the house!

• This is critical, misalignment of a coil-over can cause premature wear and even failure due to binding. Spacers or shims can sometimes be used to help correct this. Remember the coil-over is supporting the weight of the vehicle! Often heim end shocks are used to help correct this, because the ball will allow more flexibility at the mounting points. I am not a believer of this type shock on street applications and would prefer to fix the problem rather than trying to mask it. We will get into my issues more with heim ends a bit later.
• What you are looking for is shock angle in relationship to the mounting points from top to bottom.

This picture is showing us 2 problems....First, I found the four bar set up was misaligned causing the lower mount to lean forward, but could also be the mount was welded in the wrong position, the drivers side mount was correct. Second the spring is actually coming in contact with the axle tube.