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

In general, 275/70-R18 tires are approximately 0.57 inches (14.5 mm) larger in diameter than 285/65-R18 tires, resulting in a 1.7% difference in speedometer readings. Obviously, the 285 65R18 tire is wider and smaller than the 275 70R18 tire.

You don’t want an uncomfortable ride with small, unstable tires. But can a normal size tire give you a peaceful ride? Well, the answer is no. So, you must be looking for decent size tires. For your ease, we are going to make a comparison of the 285 65R18 vs 275 70R18 Tire Size. 

We’ll go over the 285 65R18 and the 275 70R18 in such a way that you can tell what size they are just by glancing at the numbers.

Let’s get the ball rolling!

How Big Is 285 65R18 Tire?

You might wonder why this tire’s name is so complex? Let us explain. The name of the 285 in the 285 65R18 tire is included because it is the distance connecting the tire’s sidewalls. The tire is 285 millimeters wide, which is 1.22 inches.

The ratio between the width and height of the tire is 65. If the tire’s height is measured as 65 percent of its width, it signifies the tire’s height is 65 percent of its width.

The R in the name appears for Radical, which is the technique in which the tire is engineered. The number 18 at the end of a tire’s name tells you how many inches wide the tire’s rim is.

How Big Is 275 70R18 Tire?

Compared to the 285 65R18 tires, the 275 70R18 width is 275 millimeters and 10.83 inches. This shows that the 275 70R18 tire is a bit smaller in width than the 285 65R18 tires.

Nevertheless, the sidewalls of the 275 70R18 measure 192.5 millimeters and 7.58 inches which signifies that the 275 70R18 is larger in height than the sidewall of the 285 65R18 tires.

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This tire is engineered in such a way that it perfectly fits the 18 inches rim of the wheel.

Head to Head Comparison: 285 65R18 vs 275 70R18

285 65R18275 70R18
Comprises a width of 11.22 inchesComprises a width of 10.83 inches
Rim width extends from 7 to 8.5 inchRim width extends from 7 to 8.5 inch
Provided with a Sidewall height of 7.29 inSupplied with a Sidewall height of 7.58 in
Offers 638.30 revs per mileOffers 627.31 revs per mile
Incredible braking and acceleration capabilityInstant braking and great acceleration ability
18 inches rim diameter18 inches rim diameter
33.16 inches overall diameter33.16 inches overall diameter is
16.29 tire radius16.58 tire radius
Performance-driven. Performance on the racetrack is expected.balanced and perfect for daily use
Has Load capacity of 3640 poundsHas Load capacity of 3638 pounds

Find out in 4 Ways Why 285 65R18 and 275 70R18 are Different.

While 285 65R18 and 275 70R18 are very similar and have so much in common in the tire world, their differences are still very significant. A small change in the tire can make a massive difference in the performance of your car. These differences will make you confused in making a decision. So, for your ease, we will explain the 4 main differences between 285 65R18 vs 275 70R18 Tire Size.


The tire’s width can be explained as the measurement of the wheel from one side to the other. You can tell the tire’s width right away by watching the tire size index—the width unit in millimeters.

Determining the width of a tire is very easy. As is evident, the first three numbers of the index of the tire size suggest its width. So, in 285 65R18, the first three numbers are 285, indicating that 285 millimeters are the width of that tire. Similarly, in 275 70R18, the first three numbers are 275, suggesting that 275 millimeters are the width of that tire. So, if we subtract 285 from 275, that equals 10 millimeters.

10 millimeters of width won’t make any difference. You can change your tire if there are 10 millimeters difference in width, more or less. As we know, changing a tire does not depend only on width. Other things to consider while changing your car’s wheel include the length of the sidewalls and the Aspect ratio.

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Aspect Ratio

The Aspect Ratio of a tire is determined by the integers or combinations that make up its size index and are measured by percentage. Besides the width, the following two numbers specify a tire’s aspect ratio. Thus, the 275 70R18 has a 70 percent aspect ratio, whereas the 285 65R18 has a 65 percent aspect ratio.

We all know that the aspect ratio and width of a tire determine how high its sidewalls are. The exact aspect ratio of 285 65R18 is 65 percent, which means that this tire’s sidewalls are 65 percent as tall as they are wide.

The method to calculate sidewall height is straightforward. The tire’s sidewall height is 275 x 70%, which equals 192.5 millimeters. Correspondingly, the other tire’s sidewall height is 285 x 65%, which equals 185.25 millimeters.

So, if we subtract 192.5 millimeters from 185.23 millimeters, the difference in the height of sidewalls equals 7.25 millimeters. That’s a huge difference; it indicates that we cannot switch the tire sizes of the 275 70R18 and 285 65R18. If you still interchange the tires, doing so will affect the car’s performance and speedometer reading. If it is crucial to change the tire size, ensure to switch all the tires.

Construction Type

The size index of the tire provides information on a tire construction type. The letter R in the size index of both tires 275 70R18 and 285 65R18 indicates the radial construction concerning construction type.

Tires with radial construction type are ideal; their premium design with square foot-prints makes driving very easy even on rough roads. Besides, these tires are water and heat-resistant. That said, they are also great power-efficient and offer incredible fuel efficiency.

Bias Ply is another famous construction type, also called cross-ply. In a tire size index, it is represented by the letter ‘B.’ This model is ideal for off-road driving.

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Rim Diameter

Rim diameter educates you on what tire size will perfectly match your vehicle. Knowing the rim diameter and size of your tire-wheel rim is crucial to understanding the ideal fit for your car. For example, you can use an 18-inch rim diameter tire if your car has an 18-inch wheel rim.

The two end numbers of the size index of the tire provide you with the rim diameter. Rim diameter is measured in inches, and the 285 65R18 and the 275 70R18 both have the same rim diameter of 18-inches.

So, this indicates you can use both tires if your car has an 18-inch wheel rim. However, ensure that all wheels have the same size tires.

Main features of 275/70R18 

Its time to get to know some of the substantial and valuable features of 275/70R18


The 275/70r18 is more cost-effective than the 285/65r18. These tires will not burn your pockets when you want to change the tires.

Great stability

275/70r18 offers excellent stability on the road. You can enjoy your ride comfortably, even on rough roads.

Width 275 mm

It has 275 millimeters in width and the distance between one sidewall from the other.

Easily Available

These tires are ubiquitous and readily available from any local dealer.

Balance performance cost and comfort

275 mm width increases the performance of your vehicle. You can get quality performance at an affordable price.


They can readily withstand the potholes and bumps that you encounter regularly. Thanks to the 70 Aspect ratio, they are durable and long-lasting.

Main features of 285/65R18

Let’s look at some significant features of 285/65R18

Width 285 mm

It has 285 millimeters in width. 285/65r18 has more distance in comparison to other tires.

Quick Acceleration

You’ll need a robust set of tires to get all that horsepower onto the track. With the 285/65r18, you will have never-before-seen acceleration.

Sporty look

These tires are lovely and are premium-looking.

Spontaneous Braking

As this has wide 285 mm width. This provides quick acceleration when you press the brakes, thus, offering more confidence while driving at relatively higher speeds.

Final Verdict

We discussed 285 65R18 vs 275 70R18 Tire Size in detail. Now it is up to you which tire you choose according to your needs. If you want good quality and affordable daily tire, you should opt for the 275/70r18. Compared to 285/65r18, they are slightly more affordable and long-lasting.

Furthermore, if you want a premium quality tire, go for the 285/65r18. You will be astounded by its quick acceleration and instant braking. Plus, these will give your car a sporty look.

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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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