Common Tire Sizes for 2026

Published: August 17, 2026

Walk into any tire shop, and you'll hear numbers like 225/65R17, 275/70R18, or 245/40R19 thrown around like everyone in the room instinctively knows what they mean. The reality is that most drivers don't, and that's fine. A tire size looks like a random jumble of letters and digits until you know what to look for.

Underneath the confusion is a standardized code that tells you almost everything about a tire's dimensions, construction, and intended fitment. Once you can read it, shopping for replacement tires gets a lot simpler.

This guide breaks down what those numbers mean, includes a tire size chart by vehicle type, and shows you exactly where to find the correct size for your vehicle.

How To Read a Tire Size

Take a tire labeled 225/65R17 102H. Every part of that code is telling you something.

Once you understand the format, comparing tire sizes side by side becomes much easier.

Understanding Width, Aspect Ratio, and Wheel Diameter

These three measurements together determine a tire's overall dimensions.

Tire Width

The first number is the tire's width in millimeters, measured from sidewall to sidewall. Generally, wider tires have a shorter, wider contact patch, and the narrower tires have a narrower, longer contact patch. The wider contact patch can provide better steering response and lateral grip, while the narrower contact patch generally provides increases in acceleration and braking traction. Wider tires can also come with trade-offs in ride quality, fuel economy, and hydroplaning resistance, depending on the vehicle and conditions.

Aspect Ratio

The second number isn't a measurement at all; it's actually a percentage. A 65-series tire has a sidewall height equal to 65% of its width. Lower aspect ratios mean shorter sidewalls, which usually translates to quicker steering response and a sportier feel. Higher aspect ratios tend to smooth out the ride and offer more cushion against potholes.

Wheel Diameter

The last number is the wheel diameter in inches. A tire marked 225/65R17 is designed for a 17-inch wheel, and that size must match the wheel you're mounting it on.

What About Speed Ratings and Load Index?

Right after the tire size, you'll usually see two more characters, something like "102H".

The load index tells you how much weight each tire can safely carry when it's properly inflated, while the speed rating indicates the tire's maximum tested speed under controlled conditions. Neither should ever be lower than what your vehicle requires.

These ratings are standardized by organizations, including the Tire and Rim Association (TRA) and the European Tyre and Rim Technical Organization (ETRTO), ensuring consistent sizing and performance classifications across tire manufacturers.

Common Speed Ratings

Common Load Index Ratings

Can You Change Tire Sizes?

Plenty of enthusiasts size up to a larger wheel paired with a lower-profile tire, or fit slightly larger all-terrain tires on a truck or SUV for more clearance and a tougher stance.

The catch is that any change in overall tire diameter alters the number of wheel revolutions per mile, which throws off your speedometer and odometer, since both are calibrated to the factory tire size. A larger diameter reads slower than your actual speed, and a smaller one reads faster.

That same diameter change also affects your ABS, traction control, and stability control systems, since they all depend on wheel speed sensor data and assume a specific rolling diameter to function correctly. Most manufacturers and tire shops recommend staying within about 3% of the factory overall diameter to keep these systems accurate and avoid throwing false codes. Beyond that, you're also changing the tire's contact patch, sidewall stiffness, and rotating mass, all of which affect handling, ride quality, braking distance, and fuel economy.

Before making a change, confirm the new tire keeps the overall diameter within that safe range and still meets your vehicle's required load capacity. Our Tire Decision Guide makes it easy to find replacement sizes that fit your vehicle correctly.

Tire Size Chart by Vehicle Type

Every vehicle has manufacturer-approved sizes, but these are some of the most common ones you'll run into today.

Important: These are examples only. Always confirm the correct tire size for your specific vehicle before making a purchase.

Tire Size Frequently Asked Questions

How do you read tire size?

In short, a tire size like 225/65R17 tells you the tire's width, aspect ratio, construction type, and wheel diameter. The numbers and letters that follow indicate load index and speed rating.

Tire Size Reference Chart

Where do you find tire size?

Most vehicles list the factory tire size on a sticker inside the driver's door opening, or look for the string of letters and numbers printed on the sidewall, something like 235/55R19. That format identifies the tire's dimensions, construction, load index, and speed rating.

Our Tire Decision Guide also helps you search by year, make, and model to pull up the correct fitment.

Find the Right Tire with Confidence

Knowing your tire size is the first step, but picking the right tire for how you actually drive matters just as much.

Tire Rack provides independent tire testing, thousands of consumer reviews, and our Tire Decision Guide that combine to help you narrow your new tire search.

New tire installation is also easy with Tire Rack thanks to our network of 10,000-plus trusted tire installers nationwide, mobile tire installation service, and free two-year road hazard protection on all new tire purchases. We also offer buy now, pay later options through Affirm and regularly have some of the best tire deals to help make your new tire purchase stress free.