Steering Gear Box vs Rack And Pinion

Over the years, steering systems have evolved and have come a long way from what obtained with the first vehicles. Most folks do not know the kind of steering systems their vehicles operate. That is why they have not optimized the benefits which come with their vehicle’s steering systems. So this article will focus on steering gear box vs rack and pinion so that the workings of steering systems are better understood.

Why is it important to understand the workings of your vehicle’s steering system? Simple.

A vehicle is nothing without a steering system that enables the driver to control its movement. The thing is, the effectiveness of automotive steering systems mostly affects passengers’ safety and the smoothness of the driving experience. You will get the most from your steering system and ultimately have a better driving experience when you understand how your car is steered.

Steering Gear Box 

The steering gear box is one of the oldest steering systems, and it is still found in the larger vehicles that we see around, for example, big body SUVs and heavy-duty trucks. To better understand how this system works, we need to understand what a steering gear is. The steering gear is a mechanical component that translates the steering wheel’s revolutions into the straight motion of the vehicle’s steering linkage.

rack and pinion vs power steering

Steering gears are often enclosed in a box hence the name “steering gearbox”. This steering gearbox holds the gears that enable transmission of the steering inputs into the linkage and other components that make the wheels turn and run properly. It essentially increases the steering changes so that the front wheels move faster than the steering wheel. Depending on the steering gearbox type, this is achieved by multiplying the turning force and transferring that force to the steering linkage.

So how does the steering gearbox work? One of the gears in the steering gearbox is the worm gear which has a block of metal with a threaded hole. The threads in this hole have many ball bearings that reduce friction while reducing play in the gear. The block is designed with gear teeth on the outside, which engages a gear that moves the pitman’s arm back and forth. The thread hole is home to a threaded rod which is in turn connected to and turned by the steering wheel. This threaded rod is designed in such a manner (it is fixed) that it rotates when the steering wheel moves. This, in turn, drives the gear that moves the vehicle’s wheels.

The steering gearbox comes with different ratios, which determine the number of times the driver turns the steering wheel to get the front wheels to turn. There is the wide-ratio box where the driver is required to turn the steering wheel for 4.5 revolutions before the front wheels turn lock-to-lock. On the other hand, the close-ratio steering box takes only 3 revolutions for the steering wheel to go lock-to-lock. Obviously, with wide-ratios, the driver has to do more work to get the wheels to turn, while the close-ratio option makes it easier to maneuver the vehicle.

The ring, which generates the steering gearbox’s resistance, can also be modified to suit your needs once the right mechanic does it. When the opposition is not correctly attuned, you get the wrong feedback from the steering, and the driving experience gets adversely affected.

So how does a power steering gear box work? With this type of steering gear box, hydraulics support the steering wheel’s movement by applying pressure to the steering system. A hydraulic pump that is attached to the engine generates fluid pressure which is released when the driver turns the steering wheel, thus reducing the steering effort.

 Advantage and Disadvantage of Steering Gear Box

Steering gear box systems are quite old, and like all old things, a newer counterpart has all but phased them out. The fact that they are still in use is a pointer to some benefits that they offer to automotive manufacturers. On the flip side, they wouldn’t be less popular now if they didn’t have some drawbacks.

 That said, let’s have a look at the advantages and disadvantages of the steering gear box.

Advantages

You could easily change the amount of steering travel to suit your needs by modifying the pitman arm length. The steering gear box has a great mechanical advantage, which is why it is best for large vehicles. It is also relatively stable and feels more solid, given its rugged design. It is also relatively easy to adjust to eliminate any backlash. A steering gearbox is great for effortless driving where there is little or no need for turns, such as driving on the freeway. It is fitted in areas of the vehicle where it’s less likely to get damaged. In some scenarios, the vehicle will still have some sort of steering control despite damage to the linkages.  

Disadvantages

The steering gear box system is comprised of several moving parts, so there is an increased risk of friction as a result of a large number of wear points. This large number of components is the cause of most steering gear box problems as it also makes the steering system relatively heavy and less efficient. Owing to the high steering ratio that it offers, the steering gear box requires a lot of steering effort, as evidenced by the steering noise when turning. Another issue is that the steering gear box price is on the high side.

Rack and Pinion

Most modern vehicles use the rack and pinion gear system. Some rack and pinion examples include cars, buses, SUVs, and trucks. As its name suggests, it comprises a pinion and a rack. The rack and pinion system simply transforms spinning motion into straight, direct motion. This probably explains why it has become increasingly popular in the automotive industry over the years.

rack and pinion steering

This steering system is popular because of its convenience, which allows it to be used on front-wheel vehicles with a steering wheel suspension that is independent. The rack and pinion design are incredibly simple as it is basically a gear attached to a bar (toothed) which is linked to a group of tie rods. Rack and pinion systems can either be manual or variable-assist power systems, but most are power-assisted.

With the manual option, the end of the steering gear shaft holds a pinion gear that is interconnected to a long rack which is attached to the steering arms by adjustable tie rods.

Vehicles with a power steering rack and pinion options come with a different design. Here, two steel tubes that are fitted on the side of the power rack are designed to perform steering functions (turning right and left) while serving as pressure and return lines.

How then do rack-and-pinion systems work? With the manual system, there is a rack-and-pinion gear set encased in a metal tube so that both ends of the rack extend from the tube. This gear set is designed to do two things. It is built to change the revolving movement of the steering wheel into the direct motion that turns the front wheels. It is also designed to reduce the effort required to turn the wheels. It does this by providing gear reduction. Since the pinion gear is linked to the steering shaft, the pinion gear spins and moves the rack when the steering wheel is turned. This movement is then translated to the tie rods, which cause the steering knuckles to spin on their ball joints. Ultimately, the vehicle wheels move from one side to the other depending on the direction in which the vehicle is being steered. That is for the manual option.

With the power-assisted steering option, the system also comes with a cylinder that holds a piston that is connected to both sides of the power-assisted rack. In this case, the rack is powered by the action of the high-pressure steering fluid on the piston.

Regardless of the option, the rack and pinion steering system are incredibly simple and highly efficient. Although the rack and pinion system is largely used in the automotive industry, other racks and pinion applications include gates, railways, and elevators.

Here are some of the advantages and disadvantages of the rack and pinion system

Advantages and Disadvantages of Rack And Pinion

The rack and pinion are quite popular because you can find them in most modern vehicles. This is mostly because of the benefits that it has over the steering gear box system. However, like with all mechanical contraptions, it is not without its failings. This section of the article focuses on the advantages and disadvantages of using a rack and pinion steering system in your vehicle.

Advantages

The rack and pinion steering system have a simple design that is just as compact as its transmission efficiency is high. Since it consists of fewer parts, the wear points are fewer and so the risks of friction are reduced. The implication is that rack and pinion repair will be fewer and far between. The rack and pinion steering systems’ price is low because it has fewer parts with low manufacturing costs and is relatively easy to produce. Since the vehicle is lighter because of the rack and pinion steering system, its gas mileage is improved.

Rack and pinion steering systems offer lower steering ratios and more control over the vehicle since less effort is required to steer the vehicle. Besides, the direct motion of the inner tie rod is excellent for geometry too.

Disadvantages

One of the disadvantages of the rack and pinion steering system is that there is less travel available because the number of teeth that can be cut into the rack is limited. Another thing is that it might be a bit difficult to retrofit this steering system into any of the older cars. If this task is not handled properly, you run the risk of poor handling.

Steering Gear Box vs Rack and Pinion Differences

The steering gear box used to be the automotive steering system of choice before the rack and pinion system stole the show circa the 1980s. Although there are still some steering gear box systems around, almost every vehicle you see these days operates a rack and pinion system. And this is mostly because of the differences in both steering systems. Like with most products, the newer rack and pinion systems are a massive improvement on the older steering gear box. Comparing the steering gear box with the rack and pinion is similar to a rack and pinion vs recirculating ball comparism because the recirculating ball system is essentially a steering gear box. That said, let us look at the points of difference between the steering gear box and the rack and pinion systems.

First off, the steering gear box system makes use of way more steering parts than the rack and pinion steering system (center links, idler arms, tie rod sleeves, and Pitman’s arms, among others). Although this makes the steering gear box a lot stronger than its counterpart, these extra parts make it quite heavy. Then there is also the increased risk of friction from having so many components come in contact with each other.

What’s more? The steering gear box has a different linkage from that which works in the rack and pinion system so they have different operations. With the steering gear box, the steering wheel is linked to a threaded bolt which turns when the steering wheel is turned. It is different with the rack and pinion system where turning the steering wheel turns the pinion gear which causes the rack to move from left to right.

That is not where the differences end. Because of the relatively large number of moving parts involved in the steering gear box system, there is more displacement and a higher steering ratio. That is not the case with the rack and pinion system, which has an improved steering ratio and is thus more responsive when being steered. The rack and pinion steering system boasts a more straightforward design, making it more cost-effective for automotive manufacturers (all thanks to the ability to automate the production of its parts). When you factor in the number of components and the size of the rack and pinion system, it’s easy to see why more automobile manufacturers opt for the rack and pinion system, especially when it is much easier to build to meet specific vehicular needs.

The rack and pinion steering system has revolutionized the steering system as it has changed the ways vehicles are being made. Automotive manufacturers can now make more cost-effective cars that are easier to steer. This is impossible to pull off with the steering gear box steering system.

Frequently Asked Questions (FAQs)

What Is The Most Common Steering System?

The most common steering system is the rack-and-pinion system. It is a simple system wherein a rack-and-pinion gear set is encased in a metal tube. Each end of the rack sticks out of the tube and is connected to the tie rod. The pinion gear is also connected to the steering shaft, so when the steering wheel is turned, the gear spins, and the rack moves. This movement is translated to the tie rods, which cause the steering knuckles to spin on their ball joints. So the vehicle wheels move in line with the direction the vehicle is being steered. The rack and pinion system is commonly found on cars, small trucks, and SUVs.

Is Steering Gear Box The Same As Rack And Pinion?

No. They are different. They have different designs and, as such different operations. Steering gear box systems have more components, are heavier, and generally less easy to handle than the rack and pinion systems. The rack and pinion system has a simple design and is more compact.

What Are The Two Types Of Steering Boxes?

The two main types of steering boxes include:

Worm and Sector: This steering box consists of a steering wheel shaft that has a screw (called “worm”). It also comes with a section gear that moves up and down when the steering wheel turns. When the section gear moves, it activates a pitman arm which rotates the wheels.

Worm and Roller: With this steering box, a roller (which replaces the section gear) is linked to the cross shaft. So when the steering wheel turns, the worm screw revolves and makes the roller rotate. Consequently, the cross shaft twists and moves the pitman arm, which forces a change in the direction of the wheels.

Can I Drive With A Bad Rack And Pinion?

It is not recommended that you drive a vehicle with a bad rack and pinion. This is because a bad rack and pinion will prevent you from getting the right amount of control required to drive your vehicle safely. There will be so much free play that it will be difficult to steer the vehicle in a straight line, which can be dangerous for you and other road users.

Why Is Rack And Pinion Steering Better Than Recirculating Ball?

The rack and pinion steering are more straightforward than the recirculating ball steering system, which has more parts. So there is less friction with the rack and pinion, and the steering feels more responsive and compact, so you get a better driving experience. The rack and pinion system is also lighter and is more efficient than the recirculating ball system. Since the rack and pinion system uses fewer parts and is thus relatively light, it is a lot easier to fit in vehicles.

Final Words

 Having read this far in this expose’ on steering gear box vs rack and pinion, you ought to have a better understanding of how both steering systems work. Many folks who are about to get a car(heck, even those who currently have one) are often concerned about things like the type of transmission, fuel economy, mileage, aesthetics, and whatnot. Most folks care less about the vehicle’s steering system because they don’t fully appreciate its significance to their safety and the driving experience.

Hopefully, you will be able to make informed decisions after reading this article. Your steering system is an essential part of your vehicle and should be taken seriously. Get an inspection to know what’s under the hood and how to make the most of it.

Osuagwu Solomon

Osuagwu Solomon is a seasoned automotive technician for the past 9 years, and a technical writer. He loves writing about auto professional repair guides, DIY repair guides, and buyer’s guide. After spending six years in the automotive workshop, he decided to impact his knowledge to people aside his domain, and he has achieved this by centering his Automotive writing skills on REPAIRS.

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