Rack and Pinion vs Steering Box SystemsLast Updated June 13, 2023 | Meghan Drummond
Your vehicle’s steering system converts your steering wheel inputs into left or right wheel movement. But it’s not as simple as it sounds. Over the decades, dozens of different steering systems have emerged, each attempting to be more efficient and durable while still improving handling.
There are two primary styles of steering system: Rack and pinion systems and steering box systems. Each system has variations, and some work better than others. We’ll go over the most common types of steering systems and their pros and cons to help you decide what’s best for your vehicle.
Steering Box Types
While most modern vehicles have adopted a rack and pinion style steering system, larger modern trucks frequently have steering boxes. They can also still be found on most classic vehicles and are preferred by some drivers.
Different types of steering boxes have been used through the years, each with its own inner workings. These are some of the most popular steering box styles and how they function.
Worm and Sector
In a worm and sector setup, the steering wheel shaft has a worm screw on the end. As the gear turns, the sector gear is moved up and down. When the sector gear moves, a pitman arm moves up and down to turn the wheels.
Worm and Roller
In a worm and roller steering box, when you turn the steering wheel the worm screw rotates and turns the rollers. Then the cross shaft twists, which moves the pitman arm.
Cam and Lever
In a cam and lever design, the worm gear rotates and activates studs on the end of the pitman shaft. This moves the pitman arm.
The recirculating ball steering box is the most reliable and tends to be what’s used in modern applications.
In this setup, the steering shaft has a worm gear at the end that’s contained within a block filled with ball bearings. The ball bearings circulate in a spiral bath along the steering shaft. This connects to a pitman arm which goes up and down, moving the track rod left and right, thus turning the wheels.
Rack and Pinion
In a rack and pinion steering box, the pinion gear turns along with the steering wheel. The rotation of the pinion gear then pushes the rack in a linear motion, directing the wheels left or right.
Though this system has been around since the 1930s, it didn’t make its way to the United States until much later. Ford introduced this steering system on the Mustang II and Pinto in 1974.(²)
The simplicity of the rack and pinion system has made it increasingly popular, and most modern vehicles use it. For classic vehicles, rack and pinion conversions are a popular modification.
Major advantages to rack and pinion systems:
- Fewer parts resulting in fewer breaks and repairs.
- Creates less friction so fewer items wear down.
- Lighter weight than most steering gear boxes.
- More compact, leaving more space for headers, a larger engine, or whatever else you plan to shove under your hood.
Both rack and pinion and steering box systems have a steering ratio. This measures how many degrees you’ll have to turn the steering wheel for the front wheels to move one degree. So, for a 14:1 ratio, the steering wheel will need to turn 14 degrees to move the wheels one.
Smaller steering ratios feel a little bit quicker. If you’re looking to convert your system, the steering ratio is a good thing to keep in mind. Buying a system with a ratio that’s a good fit for you will help you enjoy your ride’s handling more.
Changing Steering Ratios
Given how simple the inner workings of steering systems are, you may be wondering if you can change your steering ratio. In theory? Sure. But it can be more challenging in practice. There are other ways of creating more responsive steering.
Many racing and performance builds do benefit from a closer steering ratio (changing to a 12:1 has a huge effect), but that’s done by swapping the entire box. If there’s a performance spec version of your vehicle, opting for that vehicle’s steering equipment may be an easier swap.
Rack and Pinion vs Steering Gear Boxes
Despite the many advantages of rack and pinion systems, recirculating ball gear boxes still are widely used. That’s because there are some advantages to traditional steering boxes.
|Steering gear box||Inexpensive
Can adjust steering travel
|More pieces that can wear
Harder to turn
|Rack and Pinion||Simpler system
Reasons to Upgrade Your Existing Steering Gear Box
When you’re looking at new steering systems for a classic vehicle, upgrading to a recirculating ball steering box is easier than converting to rack and pinion.
Not only is it easier to install, but it will save you money and preserve your car’s vintage look. You can also adjust the pitman arm length, which gives you more freedom to control your steering travel.
Reasons to Upgrade to a Rack and Pinion
Steering gear boxes typically have more components, which makes them heavier. They’re also more difficult to handle. If you want a steering system that’s durable, straightforward, and lightweight, rack and pinion is the way to go. You’ll get better handling and fuel economy. Not to mention all the added space you’ll have for more engine mods.
Make Your Steering More Responsive
Steering is an important, and often overlooked, part of the driving experience. Getting responsive steering is a worthwhile endeavor. It’s important to note that power steering can be added to either of these systems. With power steering, turning requires even less effort.
If there’s too much play in your existing steering system, sometimes replacing your joints and bushings can make a big difference! Tie rod ends are another component that can wear down over time, creating too much play. Checking over your steering system for small but easy improvements can give you the responsiveness you’re looking for.
Sources: Steering Gear Box vs Rack and Pinion, RX Mechanic | Rack and Pinion Steering: Everything You Need to Know, Car and Driver | What is Rack and Pinion Steering, Moog | Steering Systems 101: Rack-and-Pinion vs Recirculating-Ball, MotorTrend