Steering Systems - Go Where You're PointedPosted in How To on October 1, 2010 Comment (0)
Aside from braking systems, there's nothing else that's more important than steering on your rig. Loss of steering control is annoying and inconvenient at the least and tragic and fatal at the worst. Did we mention that steering is important?
Stock steering systems are engineered for stock tires and stock suspensions, two things that usually go out the window when an off-road enthusiast gets a hold of a blank vehicular canvas. Whether your stock steering system will work properly with your modifications depends on several factors, which we'll address in this story. More than likely, you'll need to modify your steering system to match the other things you've changed.
What qualities make a safe steering system for a modified vehicle? To answer this question, we took a mini-tour to consult some experts.
Currie Enterprises was our first stop. Currie has been modifying Jeeps, trucks, and everything in between for decades. Five decades to be exact. Pitman arms, ball joints, track bars, drag links, and "death wobble" were subjects we discussed.
Howe Performance was next. Jeff Howe and crew have been rebuilding and modifying steering systems since 1984. You can find Howe steering products on a vast majority of the Baja racing field, and Howe steering systems and components are also a common sight on the backcountry trails. At Howe Performance, we had the chance to see what's inside a steering box and what's involved in a ram-assisted steering system.
Autofab is another longtime contender in the off-road world. John Ehmke launched Autofab in 1977, specializing in Ford trucks. John has also applied his expertise to fullsize Chevy trucks and SUVs and has some parts in his arsenal that no trail-going Chevy should be without.
Read on to learn more. If you can't go where you're pointed, you might as well stay home.
"'Death wobble' is actually a shimmy," John Currie informed. "It's a shimmy that's so violent it might make you think you're going to crash and die." We found out that there's no single cause of death wobble. As such, if someone tells you that they've got a sure cure for all death wobble, it's a sign that they don't have enough experience diagnosing and attempting to eliminate death wobble.
Got death wobble? Check your ball joints, track bar bushings, suspension bushings, and steering box mount. Often, one part starts wearing and in turn accelerates wear on adjacent components. Death wobble is done away with through the process of elimination. You might have to try several possible remedies before you get the front end to stop shaking. Tire balancing can play a part in death wobble, but John also told us that even though a tire might balance on a machine, it might not be round. "Newer-style tires that are made in a segmented mold run much more true," John commented.
Camber, Caster, Toe-In, And Kingpin Inclination
CAMBER: A descriptive term that refers to the front tire's angle as viewed from the front or rear. If the top of the tire is pulled in toward the vehicle, that's negative camber. If the top of the tire is pushed out away from the vehicle, that's positive camber.
CASTER: A term that refers to a line drawn through the knuckle's ball joints (or kingpins) as viewed from the side. If the upper ball joint leans back from vertical, that's positive caster. If the upper ball joint leans forward from vertical, that's negative caster.
TOE-IN: This refers to the relationship of the front wheels as viewed from directly overhead. If the tires point straight ahead, there's no toe-in or toe-out. If the fronts of the tires are closer together than the back edges, that's toe-in. If the fronts of the tires are further away from each other than the back edges, that's toe-out.
KINGPIN INCLINATION: This describes a line drawn through the knuckle ball joints (or kingpins) as viewed from the front or rear. Ideally, this kingpin inclination line will intersect the center of the tire's contact patch.
Bumpsteer refers to the amount that the steering system moves side-to-side, without driver input, as the suspension cycles up and down. The less bumpsteer you experience, the better. With a solid front axle, you want your drag link and track bar at the same angle and to be the same length to minimize bumpsteer. This isn't always possible, but it's the goal.