Ask any racer what steps to take when installing a steering system and they'll probably give you a squint-eyed, "What?" before you can say duh. That's because most racers treat the installation of the steering system the same way they treat installing a set of tires--just bolt them on and go. But the truly knowledgeable, and probably winning, racers know this question requires a very involved answer that is heavy in details. To learn more about this black art of getting your race-car steering system installed and ready to steer you to the front, Circle Track checked in with the knowledgeable and outspoken Randy Sweet, of Sweet Manufacturing in Kalamazoo, Michigan, and the chassis specialists at Craig Raudman's Victory Circle Chassis in Bakersfield, California. We doubt you've seen a lot of this steering technology before, but you can plan on seeing more details on this applied to other race cars in Circle Track. We think you'll find using the steering system to get around the racetrack quickly interesting.
The Facts
The purpose of the steering system on a circle-track car, whether it be pavement or dirt, is to transmit the steering inputs of the driver to the front wheels. The steering system should exhibit good Ackerman geometry while the wheels are being turned and minimal bumpsteer while the suspension is going up and down.
To make sure we're all on the same page, Ackerman is a steering design that causes the inside wheel in a turn to receive more steering angle than the outside tire. This is done because during a turn, the inside wheel travels in a tighter radius than the outside wheel, so to prevent dragging one of the front tires through the turn, they are turned at different angles. Bumpsteer describes the steering input the wheel sees, while the steering wheel is held steady, as the suspension moves up or down. This input is due to the different arcs being swept by the different-length lower suspension A-frame and tie rod. If this is just the least bit confusing, understand that people have dedicated their lives to understanding suspensions, and we still learn new information every day on how to make suspensions work.
Most racers are familiar with this technology and spend a lot of time getting the steering to do these tasks but, according to Sweet, they are missing one very important aspect of the steering system's job. The front wheels can never, ever, attain toe-in--front tires pointed in toward each other--especially when a car is entering a corner. While practically every circle-track racer known sets their front wheels with about 1/8 inch or more of toe-out, there are times on the race-track where the wheels will toe-in. This is bad as toe-out works best for the front suspension, steering geometry, tire deflection, and other components on circle-track cars to let the driver steer the car around the corners quickly.
Toe-in does everything to a race car you don't want to have happen. It makes the rear end want to come around the car just about every place on the track--entering the corner, exiting the corner, everywhere. This story will show you how to determine if you are getting toe-in (Sweet thinks there are plenty of racers with this problem) and how to get rid of it while you learn some other great tips on how to get your steering system doing its best.
