265 65R18 vs 275 65R18 Tire Size – Deep Comparison!

When choosing the perfect tires for your car, you need to take care of a bunch of factors, including its size, construction quality, type, cost, etc. However, tire size is probably the most important factor you need to consider, and the tire size index will help you easily estimate it.

Currently, 265 65R18 and 275 65R18 are probably the most popular tire sizes for passenger cars. But, how do you pick between the two? To answer your question, we will do a detailed 265 65R18 vs 275 65R18 tire size comparison.

You’ll know what the size index implies and how the two tires are different. So without further ado, let’s dive right in.

265 65R18 vs 275 65R18 Comparison Chart

Parameters265 65R18275 65R18
Section Width265 millimeters275 millimeters
Aspect Ratio172.25 millimeters178.75 millimeters
Revs Per Km397391
Construction TypeRadialRadial
Rim Diameter18 inches18 inches

How To Understand the Tire Size Index?

You’ll find the tire size index scribbled or painted on the sidewall of a tire. It’s consisted of letters and numbers. The size index delivers 4 crucial pieces of information about the tire, including its diameter, aspect ratio, rim size, and type of construction.

Let’s take a tire size ‘285 70R17’, for instance. Here’s what you can learn from this code-

  • The first part, ‘285’ expresses the tire’s width measured in millimeters
  • ’70’ is the aspect ratio of the tire
  • ‘R’ stands for the type of construction, which is ‘Radial’ in this case
  • ’17’ expresses the rim diameter of the tire in inches
Related:   275/70R17 vs 285/70R17 Tire Comparison

265 65R18 Tire Size – What Does It Mean?

Here’s what 265 65R18 stands for-

  • Tire Width: 265 millimeters or 10.43 inches
  • Sidewall Height: 172.25 millimeters or 6.78 inches
  • Circumference: 2519 millimeters or 99.17 inches
  • Required Wheel Rim Size: 18 inches
  • Construction Type: Radial Construction

275 65R18 Tire Size – What Does It Mean?

Here’s what 275 65R18 stands for-

  • Tire Width: 275 millimeters or 10.83 inches
  • Sidewall Height: 178.75 millimeters or 7.04 inches
  • Circumference: 2559 millimeters or 100.74 inches
  • Required Wheel Rim Size: 18 inches
  • Construction Type: Radial Construction

265 65R18 vs 275 65R18 Size Comparison

Now, let’s get into the details and find out how the two sizes are different and how it affects the performance of the tires.

1. Section Width – Which One Is Wider?

You can easily understand whether the tires are thicker or thinner from their section width. The width is measured from one side of the tire to the other at its widest part.

As you can see from the size index, the width of the two tires is 265 and 275 millimeters. So, the difference is 10 millimeters or 0.39 inches. Hence, the 275 65R18 tire size will be around 3.6% wider than the 265 65R18.

Although the difference isn’t that significant, thicker and wider tires are more durable. The 275 65R18 will withstand punctures and harsh environmental conditions better.

2. Aspect Ratio – Which One Is Better at Handling?

The aspect ratio is expressed in percentages and helps you easily measure the sidewall height of a tire. Sidewall height is measured from the top tread to the rim edge. Here’s how you measure the aspect ratio and sidewall height-

  • Aspect Ratio = Height/Width x 100%
  • Sidewall Height = Width x Aspect Ratio Percentage
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265 65R18 and 275 65R18 have the same aspect ratio of 65. However, the sidewall height of a 265 65R18 tire is 172.25 millimeters or 6.78 inches. In comparison, the sidewall height of a 275 65R18 tire is 178.75 millimeters or 7.04 inches. Clearly, 275 65R18 is a larger tire in that regard.

Now, how does it affect the performance of the tires? The shorter sidewall will be somewhat stiffer and help the vehicle to react faster. Hence, handling will be easier with a 265 65R18 tire. Steering, accelerating, and braking will be faster with this tire.

3. Revolutions Per Km – Which One Offers Higher Fuel Efficiency?

Revolutions Per Km is the number of turns the tire takes to reach a kilometer. Typically, smaller tires roll more than the bigger ones to reach the same distance.

The Revs per km of a 265 65R18 tire is 397, whereas the number is 391 for a 275 65R18 tire. A higher Revs per km value indicates the engine needs more power to reach the same distance. Hence, it uses more fuel, and the fuel efficiency decreases.

So, the larger tire, 275 65R18 in this case, will be more fuel-efficient than the smaller one.

4. Type of Construction – Good for On-Roading or Off-Roading?

How do you tell if a tire is manufactured for on-roading or off-roading? A simple look at the size index will be enough. There’s only one letter in the size index that indicates the tire’s construction type.

In modern tires, you’ll see the letter ‘R’ or ‘B’ in the size index. Here, ‘R’ refers to radial construction, and ‘B’ indicates that the tire is Bias-ply (also known as Cross-ply).

As we can see, 265 65R18 and 275 65R18 tire sizes have a radial construction. This means these tires have a sophisticated construction and square footprints on their outer diameter.

Both the tires are great for on-roading and suitable for family or passenger cars. If you want better off-road performance, you should choose tires with the letter ‘B’ in the size index.

Related:   285 65R18 vs 275 70R18 Tire Size: Detail Comparison

5. Wheel Size – Will the Tires Fit Your Car?

You must know the wheel rim size of your vehicle and the rim diameter of the tire to ensure that the tire will fit. The rim or wheel diameter is the internal circular blank where the wheel adjusts.

As mentioned, the last two digits of the size index express the rim diameter in inches. Both the tire sizes, 275 65R18 and 265 65R18, have the same wheel diameter of 18 inches.

Hence, both of them will easily fit a car wheel rim of 18 inches in diameter. It tells you how many layers were put together to manufacture the tire.

265 65R18 and 275 65R18 – Are the Tires Interchangeable?

There’s no doubt these two tires have many similarities. But, can you interchange them? Is it okay to switch only one tire to another size? Usually, it depends on the width and aspect ratio of the tire. Unfortunately, these two tires can’t be used interchangeably.

The 275 65R18 tire size is 10 millimeters wider than the 265 65R18. Plus, the sidewall heights of the two tires are different, and one is slightly thicker. So, if you want to switch, you need to change all four tires. Otherwise, the overall performance of your vehicle will not be up to the mark.

Wrapping Up!

So, there you have an in-depth 265 65R18 vs 275 65R18 tire size comparison. We discussed all the similarities and differences between the two tire sizes so that you can easily decide which one to choose.

If you want better handling and a more affordable option, go for a 265 65R18 tire. On the other hand, 275 65R18 will be a better choice for durability, fuel efficiency, and comfort. However, the differences aren’t really noticeable for most people. You should pick one as per your needs.

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Brian Polk

Brian is an automotive expert who has 12 years of experience in the industry. He has worked on a variety of cars, from high-end luxury vehicles to budget-friendly options, and has a wealth of knowledge on the subject. He is passionate about automobile and enjoys sharing his knowledge with others, whether they are looking to purchase a new motorized vehicle or simply learn more about the inner workings of these machines. In his free time, Brian enjoys working in his automobile workshop and spending time at the track.

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