Table of Contents
Is Tire Size Really Important?
Simply put, the larger your tire, the better your vehicle's traction on the road will be. The width of a tire rises as it covers more road surface area.
The terms "wheels" and "tires" are not interchangeable. The wheel arrangement includes tires. For example, your vehicle's rims have a specific size, but you can purchase different tire sizes to match those rims as long as the middle of the tire is the correct size. A vehicle with larger rims, on the other hand, will typically be able to fit larger tires than other vehicles.
Larger Tires for Larger Rims
In general, larger tires and wheels are better for enhancing traction in your car. According to Consumer Reports, however, larger tires come at a higher price. Try to strike the right balance between size and price. If you choose larger wheels and tires when you buy your vehicle, you may not notice the price difference at first, but when you need to replace them, you will pay more than someone who drives a vehicle with smaller wheels.
When it comes to tire replacements, you might want to stick to the size you selected initially. This is because a different-size tire might cause your speedometer to malfunction and possibly compromise your vehicle's anti-lock brake systems and stability system calibrations. This applies to both smaller and larger tire sizes. Changing to larger tires with an inappropriate sidewall height can harm your vehicle's suspension system, wheels, and tires, and can result in inaccurate speedometer readings.
Tips for Choosing Tires for Rims
While the average motorist may not know exactly what they're looking for when shopping for new tires, replacing tires and rims is simple if you follow a few basic rules.
When searching for new tires, you may notice different size descriptions, such as 235/75R15 and P215/65R15. You should know how to read the labels in order to understand the sizes for specific rims.
The numbers show the width of the tires from sidewall to sidewall in millimeters. The larger this value, the more road the tire has contact with. The tire type is indicated by a letter on the left side.
The letter "P" stands for passenger vehicle tires. This document also informs you that the tire is manufactured in accordance with US standards. When there isn't a letter, it signifies it's made to European specifications. The load capabilities of the two types are different.
"LT" stands for "light truck." Tire sizes beginning with these letters are designed for light trucks. They'll have greater psi recommendations to handle trailers and large loads more effectively.
The abbreviation "ST" stands for "special trailer." Tire sizes beginning with these letters are only for trailer wheels.
Using this information, we know that a P215/65R15 tire is for a passenger vehicle and has a 215-millimeter width just by looking at it.
Two numbers, a letter, and two additional numbers can be found on the right side of the slash sign. The aspect ratio of the tire's height to its width is represented by the first set of figures. These figures are 65 in our P215/65R15 example, indicating that the tire's sidewall height is 65 percent that of the tire's width. The middle letter on the right side of the slash indicates the tire's construction method, which is usually "R," which stands for radial. This indicates that the tire's layers run radially across it. The last number is crucial since it indicates which rim size the tire will fit. This number in our case is 15, indicating that the tire will fit a 15-inch diameter rim.
Having different sized tires and rims for the front and back wheels, known as staggered tires, is sometimes acceptable. This is especially common on muscle cars like the Mustang, Challenger, and Camaro. This works because the back wheels do not have to turn as much as the front wheels.
The larger your rim, the more difficult and costly it will be to replace your tires. Thinner tires are usually associated with larger wheels. The tires must be small enough to fit within the wheel well. The thinner your tire is, the less it can handle rougher roads and potholes, resulting in blowouts.
Your vehicle's wheels and tires are critical components. Though it may seem self-evident, many drivers don't pay much attention to the tires they purchase for their vehicles, which can lead to a variety of issues.
How Much Rubber Will You Require?
The contact patch—specifically, how much of the tire meets the ground at any given time—is one of the reasons why people choose larger wheels and tires. Perhaps you've upgraded your engine for more power, and now your tires are bursting at the seams. Therefore, you'll need greater contact with the ground (and hence more grip).
You could also want to increase the diameter of your wheels while you're adding width. Then, for improved handling, you can install a tire with a wider tread and a lower profile. Because of the reduced profile, the overall diameter of your wheel and tire combination remains relatively constant. A Plus 1 upgrade is when the wheel diameter is increased by an inch while the sidewall of the tire is reduced by the same amount. On most vehicles, we can even go further lower in profile with a Plus 2 (for example, going from 16 to 18-inch wheels) or Plus 3 (16 to 19-inch) upgrade without any issues.
Downsizing your wheels works on the same premise as changing the diameter of your wheels by an inch while adjusting for the inch difference in the height of the tire's sidewall. You won't notice any changes in your speedometer if you keep the overall diameter of your tires the same—the frequency at which your wheels spin is commonly used by speedometers to calculate your car's speed. Your speedometer will not give you an accurate speed if you have a considerably different tire diameter that causes your wheels to turn more or less frequently than they used to.
Geometry Is Everything
When searching for new wheels and tires for rims, there's one more item to consider: how does everything fit together?
A centering hub is a raised component that aligns with a matching recessed element of the wheel in many autos. Its purpose is to keep the wheel centered on the hub more precisely than simply tightening the lug bolts. Some wheels may not fit well in this hub, necessitating the use of a spacer or even a new wheel.
In addition, the replacement wheel must have the proper offset in order to clear the suspension and brakes. The offset is the distance between the centerline of the wheel and the hub mounting surface, the point where the rims meet in the middle. It determines how far the tire extends laterally from the wheel hub.
Tire Quality Grading
The Uniform Tire Quality Grading, or UTQG, is another important factor to consider. For passenger car tires (i.e. P-metric and Euro-metric) in the all-season and summer categories, this grading and stamping are necessary. This rule, however, does not apply to dedicated winter tires, light trucks (LT-Metric, Euro-Metric Commercial, Flotation), or motorcycle tires.
The purpose of quality grading is to make your tire purchase selection easier. The system's goal is to provide easy, comparable facts so you can make an informed purchasing decision. On the other hand, the ratings are based on test findings obtained under unusual circumstances. This means that the comparable data could be misinterpreted as it applies to your own driving patterns, situations, and so on. You should still seek assistance from your service or tire professional.
How Do I Know What Size Tire I need?
It's important to understand how tire sizing works if you want to be sure what size will fit the rims. When selecting new tires for rims, there are three factors to consider: size, speed rating, and load index. To ensure optimal performance, safety, and fuel efficiency, it's critical to make the right choice.
Selecting a different size for winter tires is common among many drivers. Without increasing the overall tire diameter, retailers frequently advocate switching to a smaller wheel and utilizing a tire with a taller sidewall. This results in a larger contact patch, or the area where the tire touches the ground. Snow traction can be improved by having a larger contact patch. (However, a wider tire reduces winter traction by plowing through snow or even floating on top of it, similar to hydroplaning)
Alternatively, you might go with a larger wheel and a tire with a shorter sidewall. This can be done for a variety of reasons, including fashion and improved three-season handling (a short sidewall has less roll, while lower-profile tires are often suited for grip).
A set of custom rims with the right style and finish can completely transform the look of your car or truck. Start shopping right now or visit a Wheel Discovery Center at your local Les Schwab. You may browse exact sets of custom wheels based on your vehicle's make, model, year, and color. This is a terrific approach to sort through all of your possibilities and narrow down your selections before making a decision.
It is crucial to select tires that properly align and fit well with the rims. You must consider the following safety factors:
The rim and tire blend should always clear the vehicle's body, suspension components, and braking components. This is vital whether you want your wheels to be larger for a more street-worthy appearance or smaller for more tire sidewall and greater off-road performance.
Offset and Backspace
Knowing how far inside and outside the complete wheel and tire package will lie in the wheel well is crucial for optimum clearance. Improper backspace or offset can create interference with body and steering components, as well as a reduction in turning radius.
Many modern automobiles come with wheels that fit perfectly around the hub right out of the factory. This is known as hub-centric fitting, and it aids in the consistent centering of the rim and tire combination when installed on the vehicle. This reduces the risk of vibrations in the seat or the steering wheel while driving by lowering the imbalance. When it comes to aftermarket wheels, our crew understands the importance of maintaining a hub-centric fit.
How to Choose the Correct Size
When acquiring new wheels, there are a variety of sizes to consider. Plus sizing increases the width of your wheels while lowering the profile of the tire sidewall to match the manufacturer's recommended total tire diameter. Minus sizing allows for a taller sidewall by working in the opposite direction.
Bolt Pattern Is Important
There are many different bolt patterns, and your new custom wheels must match to fit your car properly. There's no guarantee that every five-hole wheel will fit your car, even if it has five lugs.
Examine the Technology
Compatibility with TPMS (Tire Pressure Monitoring System) is also critical. The TPMS in your car should be reset after installing new wheels, as it is in most new vehicles.
Keep in mind that your options will be limited to your vehicle's make and model. Many drivers consider the sizes of their wheels and tires primarily for aesthetic reasons. However, wheel size — and the size of the tires you place on them — are important considerations. Using the wrong tires for rims can be expensive and even dangerous.
About The Author
I've spent many years selling cars, working with auto detailers, mechanics, dealership service teams, quoting and researching car insurance, modding my own cars, and much more.Read More About Charles Redding