The Stovebolt Site Forums The Shop Area Driveline Camber, Toe in/out, and caster on a stock 3600

OP, you say you are running radial tires. Is that on the original wheels? Probably not I'm guessing. So determine the wheel offset as compared with stock. Stock setup should have the imaginary line through the kingpin hit the ground at the center of the tire. On these trucks that will require a positive offset, more so with wider wheels. I have found that a 6 inch, zero offset wheel is acceptable in terms of steering. The problem you describe is one I had running 7-inch zero offset wheels and even worse with 8-inch wheels, even with narrow tires. With original wheels and bias ply tires it steered just fine.

Too much caster will make the truck steer heavy and follow the ruts and tar strips in the road. Caster is usually set with more on one side so the steering will pull toward the crown of the road. I have changed the tapered shims in mine years ago to get it to steer like I wanted but I don't remember the angle of shims I used. I set it to the factory spec and to pull toward the crown. FWIW I have also used them on the rear axle to get the u-joint angles to match. For no vibration they need to be withing 1/2 a degree of each other.

As for camber, radial tires like just about 0 for camber and toe. if the outside of the tire is wearing it usually indicated too much tow-in. Shops used to add toe in to compensate for loose king pins. Then when you put new king pins in there's too much toe in. I use about 1/16" and it might be too much. On bias ply tires outside-shoulder wear usually indicates too much camber but it doesn't affect radials much. As you know, changing camber requires a big-truck shop that can bend axles. I once worked in such a shop and spent too much time at the chiropractor. It was heavy work. Big wrenched and big port-a-powers.