Project Old School: Camber Correction

Ever wonder why those trucks you see sitting flat on their framerails have front wheels that lean inward at a 45-degree angle? The answer is camber. Camber is the measurement of tire lean in degrees. If the top of the tire tilts inward, the vehicle has negative camber. Typically, a truck at stock height is set with about a 1/2-degree of negative camber for optimum performance. When a truck is lowered by using coils, the suspension is now set higher in its arc of travel--thereby increasing the amount of negative camber. Oftentimes, the effects of simply installing a shorter coil can be corrected by installing shims or rotating a cam to push the upper control arm out. But once you lower the truck beyond what can be corrected by adjustment, you will be forced to "set the toe and let it go," which is what most alignment shop guys say when they see a lowered truck pulling in for service.

Fortunately for all of us '63-72 GM truck owners, Performance Online has come to our rescue. In addition to offering just about everything you need chassis and suspension wise for '47-72 Chevys, '48-56 Fords, and '55-72 GM cars, they recently developed tubular upper control arms that help to correct the geometry on moderate to severely lowered rides such as mine. Besides looking really cool, the arms are 3/8-inch longer than stock. This means you can align even the lowest of trucks. They also moved the location of the upper ball joint slightly rearward to add an extra 2 degrees of caster to the arm--helping the truck to drive straight and true. Finally, the angle of the ball joint was rotated slightly so it would meet the spindle at the correct angle. The tubular control arm kits come with brand-new factory cross shafts already installed. Performance Online also offers new bumpstops and all three of the possible ball joints for your application-- giving you truly one-stop shopping.

I rolled Old School into the Performance Online installation center at about 9:00 a.m. and was back on the road by 11:00 a.m., so needless to say, this is a simple installation. As always, contact Performance Online for more information on this or any other product they carry.

With the stock control arm up and out of the way, the two lock nuts that hold the cross shaft to the frame were removed. The arm was removed, and the plethora of thick shims fell to the floor.	In this comparison shot you can clearly see four things: the tubular control arm is slightly longer than the stocker; the angle that the ball joint mounts is corrected so it will be true to the spindle; the ball joint location is moved back on the arm slightly to add caster; and the tubular arms look a lot cooler than stamped steel ones.	A better angle of the stock control arm shows just how bad the ball-joint angle can get on an extremely lowered application (the hole in the spindle is vertical).
With the arm out of the way, the frame studs and mounting areas were cleaned and lubricated.	Performance Online also offers these shorter spacers (left) that fit between the cross shaft and the frame. Using them will add an extra 1/8-inch of adjustability to the arms if your truck is only slightly lowered or was running minimal shims to begin with.	Before the tubular arm was installed, the flange of the crossmember was trimmed back slightly for added clearance. Then the spacers were slid back into place.
New ball joints were then bolted to the arms with new hardware.	The new arm was then fit over the studs and double-checked for clearance against the frame.	Based on the shims that were on each stud with the stock arm, we subtracted significantly but kept the approximate ratio. In other words, this side started with about 1/4 and 3/8, and we ended up with 1/16 and 1/8. Then we set the vehicle down and held a level vertically to the outside edge of the wheel. This is a glorified version of "eyeballing it," but it will get you down the road and to your appointment at the alignment shop.
With our guestimate number of shims installed, we torqued down the new nuts to spec.	Now the ball joint could be dropped into the spindle and locked down with a new cotter pin.	Before dropping the vehicle down, we hit the three new fittings with the grease gun.
With the airbags completely deflated, I got this shot of the newly corrected ball-joint angle. Notice how true the arm and spindle are in relation to each other.	There it is: significantly better suspension geometry in a couple hours, and an airbagged truck that will align at ride height with no hassles. I'd say this was a morning well spent.