You can't go a single day on the road without seeing semi-trucks. They're an integral part in the world of logistics, so they're certainly a common sight. One thing you can't help but notice about these vehicles is their tires. Exactly how big are they? We have researched semi-truck tires and have the answers for you.
There are several standard sizes of semi-truck tires currently used, but some of the most popular sizes include:
- 295/75R22.5
- 275/70R22.5
- 225/70R19.5
These are tires with widths of 225 mm-295 mm. They also have a height to width ratio, also known as an aspect ratio of 70-75, and a rim diameter of 19.5-22.5 inches.
This article will discuss how big semi-truck tires are and how to read a semi-truck tire's size. We will also learn about other semi-truck tires related questions. Keep reading to learn more.
How Big Are Semi-Truck Tires?
Semi-truck tires are a bit larger than standard car tires. A typical size for a car tire would be a size like 235/40R18, which has a tire width of 235 mm. A semi-truck tire typically has a size around 225/70R19.5 and 295/75R22.5, which has a tire width between 225-295 mm.
Also, the car tire has an aspect ratio of 40, which means that the tire, from the rim to the tread, is 40 percent the length of the tire's width. The larger aspect ratio on a semi-truck tire makes it taller. A semi-truck tire's rim diameter is larger than the 18-inch diameter on the car's tire.
Overall this makes semi-truck tires bigger than standard car tires. This makes sense when you think about how much more weight a semi-truck tire has to carry. Also, semi-trucks drive for longer hours than a typical residential vehicle. The additional weight the truck has to carry in addition to the long driving hours puts a lot more wear on the tires, so they need to withstand that.
How Do You Read A Semi-Truck Tire Size?
When you read the tire size on a semi-truck tire, you will see some numbers and letters arranged like this: 225/70R19.5.
On GCR Tires, they break down the four main parts of a semi-truck tire's size.
Width Of Tire
The first number from our example is '225.' This is the tire's width in millimeters. This is the number that the next section references to understand tire height.
Hight of Tire
The height of the tire isn't just listed like the width. Instead, it is written as a ratio of the width of the tire. So in the example, after the slash is '70.' This means that the tire's height, from the rim to the edge of the treads, is 70 percent of the tire's width.
Tire Type
The letter after the number '70' in our example is 'R.' This lets us know that the type of tire is radial. This means that the tire is supported with steel belts that run radial inside the tire. There are other types, but radial is the most common for truck tires.
Rim Diameter
The rim diameter is the diameter of the center of the tire. This lets you know what size rim wheels fit inside this tire. In the example, it would be the '19.5' at the end. This indicates that the rim diameter is 19.5 inches across.
Why Are Semi-Truck Tires So Big?
Semi-truck tires are big to allow for more traction and stability while driving. Semi-trucks can move thousands of pounds of cargo across thousands of miles. It can be crucial that the tires on them are up for such a long job.
Wider tires help to distribute the weight across more surface area, while taller tires mean the tires can rotate less and cover more distance. Also, with more rubber between the road and the truck, there is more material to use up over time. This will improve the time between tire replacements.
How Do I Choose A Semi Truck Tire?
When you are choosing tires for your semi-truck, it is good to know what your options are. You will want to read your truck's owner manual to see what tires it recommends in different situations. In some cases, your vehicle may need different tires than in another situation.
- Start by making sure that the tire's width and aspect ratio work for your vehicle.
- Then check the tire type. In most situations, you want 'R' for radial.
- Now be sure that the rim diameter matches your vehicle's rim diameter.
- If all of the tire's specs meet the requirements of your vehicle's owner's manual, then you know that the tire will work.
Be sure to choose the right tire for the right vehicle and situation. You will want larger treads for off-roading than a long drive across Kansas.
How Long Are Semi Truck Tires Good For?
Lube Zone says that semi-truck tires have a life span of three to six years. It is recommended that you change your tires no less often than every six years. If the tire has more wear or damage, then it may need to be replaced sooner, like three years.
One more thing to know when changing semi-truck tires is about changing them in pairs. When you change a semi-truck's tires, you want to change the opposite side tire as well.
When the treads on two adjacent tires are uneven, it can cause issues when you drive. This is why it is recommended to change all of your semi-truck tires in pairs.
What Is A Steer Tire?
Steer tires are the tires in the front of a vehicle that are used to steer. They are designed a little differently than other tires to optimize their position on the vehicle. Since they are in the front and used to steer, they are designed to have lots of traction to control the vehicle better.
These tires also tend to be built stronger than other tires since turning your vehicle wears them out. By having higher endurance, they can help the tires in the front and back wear more evenly.
On a semi-truck, there are two other tires we will also talk about.
What Is A Drive Tire?
A drive tire is usually located just behind the steer tire on a semi-truck. These are the tires that are hooked to the drive train and push the vehicle forwards.
To help increase traction with the road, these tires have stronger treads. Since the truck's power is based on how hard the truck can push off the road, the tires have to have a lot of traction.
If you tried to use a different tire where the drive tire was supposed to go, your vehicle wouldn't be able to grip the road. This would result in less available power for the semi-truck. Drive tires can be essential to maintaining efficient trucks.
What Is A Trailer Tire?
A trailer tire is a tire that is usually located at the back of a semi truck's trailer. These tires don't receive power from the drive train and also don't help in steering. For this reason, they don't need to have as strong of treads. The forces on these tires are greatly lower than their counterparts.
Do Steer Tires Have To Match?
When you are installing steer tires, it is a good practice to make sure that they match. When your vehicle has different size steer tires, then the vehicle will handle incorrectly. You may notice that you slide when you shouldn't or don't turn correctly. So make sure that your steer tires match.
Now, what if you are in a situation where you have no choice but to use mismatched steers tires temporarily. How much damage will this cause to your vehicle? Overall this won't do any severe damage to the vehicle but, it does reduce the vehicle's handling. If you must drive without matching steer tires, go slower to help keep yourself safe.
What Are Semi-Truck Tires Made Of?
Semi-truck tires, like most tires, are made from a blend of natural and synthetic rubber. This rubber is layered in different configurations depending on the specific tire.
Semi-truck tires are built with lots of hard rubber layers to make the tires extra resilient. On the other hand, standard car tires are also made with layers of rubber, but the rubber they use is not nearly as dense. They also don't use as many layers.
There are also other special layers they can add to a semi-truck's tires to improve performance. One of these things is a polyester layer that helps to prevent the tire from overheating. It also adds a layer of rigidity to help the tire hold its shape.
Final Thoughts
In this article, we learned how big semi-truck tires are and how to read their size. We also learned that semi-truck tires are big to increase traction and stability. Also, larger tires last longer since they have more rubber.
Next, we covered the different types of tires and how it's essential to keep your drive tires and steer tires in the correct location. Finally, we learned that tires are made from different rubber layers of varying densities. The density affects how well the tire will endure. Semi-truck tires are usually denser.
We hope you enjoyed this article. If you would like to learn more, check out these other posts.
How Many Miles Does A Semi Truck Last?
Should Good Tires be On Front Or Back?
Has a semi Tire 295/75R22.5 ever been fitted on a typical pick up truck for Height and aesthetic looks