Wheel Insights

How to Read Tire Size Codes and Ratings: A Macon, GA Guide

By Peter Green

Tire size codes like P215/65R16 95H decode your vehicle’s fitment: the P means passenger tire, 215 is width in millimeters, 65 is the aspect ratio, R indicates radial construction, and 16 is wheel diameter in inches. The 95 is a load index, and H is a speed rating. The Magic Wheels store on Eisenhower Parkway in Macon installs tires same day, with installation included.

Key Takeaways

A tire size such as P215/65R16 95H gives the tire class, width, aspect ratio, construction, wheel diameter, load index and speed rating, in that order.
The first number is section width in millimeters; the number after the slash is sidewall height as a percentage of that width.
R means radial construction, and the number after it is the wheel diameter in inches the tire fits.
The load index sets the maximum weight each tire can carry, and the speed rating letter sets its maximum sustained speed.
Your vehicle’s correct size is on the driver’s doorjamb placard and in the owner’s manual; replacements should meet or exceed it.
The Macon store on Eisenhower Parkway serves Bibb County and nearby towns including Warner Robins, Byron and Gray.

What do tire size numbers mean?

Tire size numbers decode the exact dimensions and capabilities of a tire. A marking like P215/65R16 95H contains everything needed to match a tire to your vehicle.

Reading a tire size starts with the first letter. That letter identifies the tire class. P stands for passenger vehicle tire. The numbers that follow specify width, aspect ratio, and wheel diameter. The final characters indicate load capacity and speed limits.

How do I find my tire size?

Locate the correct tire size before shopping for replacements. Check inside the driver’s side doorjamb first. The owner’s manual also lists the factory tire size. Write the full code down before you shop, including the load index and speed rating at the end. Matching these specifications ensures the replacement tire fits your vehicle’s requirements.

What does each part of the tire size code mean?

Break down P215/65R16 95H into five components:

P identifies the tire as a passenger vehicle class.
215 represents the tire width in millimeters.
65 is the aspect ratio, the sidewall height as a percentage of width.
R16 indicates radial construction and a 16-inch wheel diameter.
95H shows the tire load index and tire speed rating.

The tire load index number corresponds to a maximum weight capacity. The speed rating letter indicates the top speed the tire handles safely. Understanding how to read tire size prevents ordering the wrong fit.

What do the letters before the size mean?

P means passenger car tire.
LT means light truck tire, built for heavier loads and towing, common on pickups and larger SUVs.
ST means special trailer tire and belongs on trailers only.
T means temporary spare.
A size with no letter at all is a metric (often called Euro-metric) size, rated slightly differently from P-metric.

How do you read tire width and aspect ratio?

Tire width and aspect ratio appear as the first two numbers in the sidewall sequence. A marking like 215/65R16 breaks down into a 215-millimeter section width and a 65-percent aspect ratio. Misreading either number leads to clearance problems, speedometer error, and compromised handling.

What does the first three-digit number on a tire mean?

The first number is the tire width in millimeters, measured from sidewall to sidewall. A 215-millimeter tire is narrower than a 245-millimeter tire. This measurement directly affects contact patch size, steering response, and whether the tire clears the fender and suspension components.

How does aspect ratio affect ride and fitment?

The two-digit number after the slash is the aspect ratio. It expresses sidewall height as a percentage of the tire width. A 65-series tire has a sidewall equal to 65 percent of the section width. Lower ratios deliver sharper turn-in and a firmer ride. Higher ratios absorb more road impact and protect wheels from pothole damage.

Multiply the width by the aspect ratio as a percentage to get sidewall height; a 215/65 tire has a sidewall of about 140 mm (215 x 0.65).

The online wheel visualizer previews wheel and tire combinations on your own vehicle, so you can see how a change in size alters the stance before you buy.

What is a tire load index?

A tire load index is a numerical code on the sidewall that specifies the maximum weight a single tire can support when properly inflated. This number appears right after the tire size and before the speed rating letter. Ignoring the load index when replacing tires compromises your vehicle’s handling, braking, and safety at highway speeds.

Manufacturers strongly recommend using tires equivalent to the originals in size, quality, and performance when replacement is needed. The load index is a critical part of that equation. A tire with too low a rating cannot safely carry your vehicle’s weight, especially when loaded with passengers and cargo.

How do you convert a load index to pounds?

The load index is a code, not a direct weight. To find the load capacity in pounds, a standard chart is used to convert the number. For example, a load index of 91 equals 1,356 pounds per tire, 95 equals 1,521 pounds, and 100 equals 1,764 pounds.

To understand the total capacity of a set of four tires, multiply the per-tire load by four. Additionally, light truck tires (LT) often feature a load range letter such as C, D, or E. This letter reflects the ply rating and the tire’s maximum inflation pressure.

What happens if you choose the wrong load index?

A lower load index than specified means the tire operates beyond its design limits. This causes excessive heat buildup, accelerated tread wear, and a higher risk of sudden tire failure. You lose predictable cornering response and increase stopping distances.

Technicians handle mounting, balancing, TPMS, and torque-to-spec installation in house. Installation is included with wheel and tire purchases and is done same day, so you drive away with tires matched precisely to your vehicle’s requirements.

How do you decode a tire speed rating?

A tire speed rating is the letter at the end of the tire size code. The letter indicates the maximum speed the tire handles safely. For example, in P215/65R16 95H, the H is the speed rating.

What are the common speed rating letters?

S = 112 mph
T = 118 mph
H = 130 mph
V = 149 mph
W = 168 mph
Y = 186 mph

The rating assumes correct inflation and a load within the load index; it is not a recommended driving speed.

What does the H in a tire size mean?

The H rating means the tire is certified for sustained speeds up to 130 mph. Most passenger cars and crossovers use H-rated or similar tires. Your owner’s manual lists the minimum speed rating for your vehicle. On a long run up I-75 toward Forsyth, you are holding sustained highway speed for an hour or more, which is exactly what the speed rating covers.

Balance and rotation stay free for the life of the tires at all ten locations. The lowest-price guarantee meets or beats any competitor’s advertised price.

What other markings appear on the sidewall?

How do you read the DOT date code?

The DOT code on the tire sidewall ends with four digits indicating the week and year the tire was manufactured. For example, the number 2524 means the tire was made in the 25th week of 2024. It is important to check this code before purchasing, since tires can sit in storage for a long time before sale.

What do M+S and the treadwear number mean?

M+S stands for mud and snow and represents a tread design rating. It does not mean the tire is a winter tire. The Uniform Tire Quality Grading (UTQG) system also appears on tires. This grading shows treadwear, traction, and temperature resistance. Treadwear is a comparative number where higher numbers indicate longer-lasting tread. Traction grades are AA, A, B, or C, and temperature grades are A, B, or C.

How do I choose the right tire size for my car?

What happens if I install the wrong tire size?

Installing the wrong tire size affects various vehicle functions. The speedometer and odometer may give incorrect readings. Anti-lock braking systems and stability control rely on accurate wheel-speed data, which the wrong size can disrupt. Additionally, a tire that is too large can rub against the fender liner or suspension when turning fully.

Getting the size right the first time costs far less.

Can I change tire size when I upgrade wheels?

When installing larger wheels, it is common to use lower-profile tires so the overall tire diameter stays close to original. Keeping the diameter within about 3 percent of the factory size helps maintain speedometer accuracy.

For example, a 215/65R16 tire and a 225/55R17 tire have overall diameters within about 1 percent of each other. The online wheel visualizer allows you to preview how new wheel and tire combinations will look on your vehicle before purchasing. Installation is included with wheel and tire purchases and done same day.

Frequently Asked Questions

Where do I find my vehicle's correct tire size?

On the placard inside the driver’s doorjamb and in the owner’s manual.

Can I use a tire with a higher load index or speed rating than the original?

Yes; a higher rating is acceptable, but never go below the factory specification.

Is installation included when I buy tires?

Yes; installation is included with wheel and tire purchases and done same day, with mounting, balancing and TPMS handling in house, and balance and rotation are free for the life of the tires.

Can I spread the cost of new tires?

Magic Wheels offers its own rent-to-own and lease-to-own plans that end in ownership, with no credit needed, pre-approval up to $3,000 in about 20 seconds, and an early purchase option that reduces the total cost.

What areas does the Macon store serve?

The store at 1209 Eisenhower Pkwy serves Bibb County and Middle Georgia along I-75 and I-16, including Warner Robins, Byron, Gray, Forsyth and Perry; Magic Wheels has ten stores in all.

Bring the code from your doorjamb placard to Magic Wheels at 1209 Eisenhower Pkwy in Macon, where installation is included and done same day.

Wheel Insights

How to Read Tire Size Codes and Ratings: A Macon, GA Guide

Key Takeaways