For most of the history of the automobile, there have been two major types of steering systems: "recirculating ball" setups found on older vehicles, and "rack-and-pinion" setups on newer ones. (This is a generalization, of course: some early 1950s British sports cars had rack & pinion, while some very late-model German luxury cars continued with recirculating ball.)
Rack-and-pinion steering racks gained popularity as a mainstream choice for a number of reasons. First, they're simpler in design and contain fewer parts. This reduces the overall amount of friction created during movement, and it means an entire steering rack only has two wear points on each side - as compared to a higher number on recirculating ball setups.
Because they don't have so many beefy parts, rack-and-pinion setups weigh significantly less. Fewer parts also means the whole system will fit in a smaller space, freeing up room for headers, big engine swaps, and other performance-enhancing upgrades. Additionally, because there's a direct, straight-line connection from the steering column to the wheels, rack-and-pinion setups provide a tighter, more responsive steering feel with less slop and numbness.
These are benefits you'll greatly enjoy on any vehicle, whether it's a classic vehicle used for cruising, a musclecar used for competition, or a 4x4 used off road.
In this article, we'll take a look at the difference between recirculating ball and rack & pinion steering setups. Then, we'll highlight some performance rack-and-pinion kits designed to let you upgrade from a recirculating ball setup (and even a few that upgrade your existing rack & pinion). Because they bolt easily in place of your OEM steering box, our performance steering kits make it possible to enjoy the benefits of modern rack-and-pion steering on an older ride - without having to perform major surgery such as welding or replacing a subframe.
Recirculating Ball Design
A typical recirculating ball steering box features a "worm" gear at the end of the steering column. This gear is contained within a block that's filled with ball bearings. As the steering wheel is turned and the worm gear rotates, the ball bearings recirculate and cause the position of the block to move. Linkage pieces known as Pitman arms, idler arms, and outer tie rod ends send that movement of the block to the front wheels, causing them to turn.
A rack-and-pinion assembly is encased within a metal housing shaped like a tube. Inside that tube, a pinion gear on the end of the steering column spins as you turn the wheel. That toothed round gear moves a long, flat toothed "rack" from side to side. Tie rods at both sides of that rack provide a direct connection to front wheels. Housings designed with power assist feature a piston (within a cylinder) that draws boost from the power steering pump via fluid lines positioned on each side of the cylinder. This pressurization moves the steering rack without great physical effort from the driver.
Definition Of Steering Ratio
One performance metric you're likely to come across when shopping for rack-and-pinion setups is a numerical steering ratio, expressed in a fashion such as "18:1". This 18-to-1 ratio means that for every 18 degrees of angle the steering wheel is turned, a steering rack will cause the front wheels of the vehicle (specifically the inner wheel) to rotate 1 degree.
A rack with a lower first number in the ratio figure, such as 13:1, means the steering wheel only needs to be turned 13 degrees for a 1 degree wheel rotation. Compared to the 18:1 rack, this one will have a more responsive steering feel. The 13:1 rack could also be described as having a "quicker" steering ratio. Naturally, fewer number of steering wheel rotations will be required to turn the rack from one extreme lock position to the other.
Bolt-On Conversion Kits
When it comes to performance rack-and-pinion ugrades, we've got power-assisted ones from Flaming River with a "custom cradle" bracket that bolts to factory holes used for the old steering box and idler arm. These are also available without cradle bracket for those that prefer to do their own fabricating. And if you want to cut maximum weight for straight-line drag racing applications, the Flaming River Manual Rack-And-Pinion provides a setup without power assist.
We've also got the Unisteer Rack-And-Pinion Conversion Kit, Rack-And-Pinion With Mounting Hardware, and quick-ratio Rack-And-Pinion Kit (check all three Unisteer kits for vehicle make and model compatibility.)
Rack & Pinion Upgrades
Got a 1979-93 Fox-body Ford Mustang? If so, you'll appreciate two AGR replacement rack-and-pinion setups that feature quicker-than-stock steering ratios. Choose a 20:1 ratio, or an even tighter 15:1 ratio to sharpen your cornering ability noticeably.
All of the kits mentioned in this article are vehicle-specific. That means these racks are designed to fit within the space available for specific makes and models they're built for. They are also equipped with mounting hardware or brackets sized and spaced for easy bolt-on installation using the mounting locations of your existing OEM system.
When you consider the gains you'll achieve in handling, safety, weight reduction, and pure driving enjoyment, a performance rack-and-pinion conversion kit is worth every penny. To help you with any inquiries you may have, our knowledgeable product reps are standing by seven days a week - so give us a call!