265/70r17 vs 285/70r17 Tire: What’s the Difference?

People often become confused about measuring near similar tires. They think similar tires can be interchangeable. But sometimes it goes wrong and causes a serious accident.

For example, 265/70r17 and 285/70r17 tires. Newbies assume they’re easily interchangeable. But it’s not what they think. 285/70r17 is a larger version and they don’t fit well in the place of 265/70r17.

Here you would find the in-depth researched result if they are interchangeable or not. Let’s find out what’s the difference between the two tire sizes.

265/70r17 vs 285/70r17 Tire: Are They Interchangeable?

So, we’ve clearly stated the tire models aren’t interchangeable. But we’re yet to define why. Thus, let’s go straight to the comparison chart.

265/70r17 TireType285/70r17 Tire
31.61 Inches or 802.8 mmDiameter Difference 1.1 (28) 3.5% inches (mm)32.71 Inches or 830.8 mm
10.43 Inches or 265 mmWidth Difference 0.79 (20) 7.5% inches (mm)11.22 Inches or 285 mm
99.29 Inches or 2522.07 mmCircumference Difference 3.46 (87.96) 3.5% inches (mm)102.76 Inches or 2610.04 mm
7.3 Inches or 185.5 mmSidewall Height Difference 0.55 (14) 7.5% inches (mm)7.85 Inches or 199.5 mm
638.1 RPM or 396.5 KMRevolutions per mile Difference -21.51 (-13.36) -3.4% (km)616.6  RPM or 383.14 KM

The first noticeable change is the diameter. When you install larger tires on short-profile vehicles, the chances of blowouts increase. As the difference here is around 3.5%, 265/70r17 and 285/70r17 are interchangeable with tons of risks. 

And most importantly, the sidewalls of the 285/70r17 tire are 7.5% higher which would create some problems if your vehicle is a performance car. Bigger sidewalls can reduce car performance although they can help to achieve fuel efficiency and riding comfort. 

Moreover, 285/70r17 is 7.5% wider than 265/70r17. Because of this, you’d have a rough experience when 285/70 replaces 265/70.

Last but not the least, 285/70 tires surely decrease the speed of a vehicle. Using this type makes the car drop at least 21.51 RPM. But still, it might not be a problem in most cases.

How to read the tire sizes 265/70r17 and 285/70r17?

There are four parts to the tire size 265/70r17, and each part bears a certain meaning. Before you decide to interchange or replace the tires, you must learn about them. Here is the explanation of each part of the tire size 265/70r17.

  • 265 indicates the width of the tire in millimeters
  • 70 indicates the percentage of height in relation to the width or the Aspect Ratio
  • R indicates Radial Construction
  • 17 indicates the Diameter of the Rim

Doing the Same for Tire Sizes 285/70r17

  • 285 indicates the width of the tires in millimeters
  • 70 indicates the percentage of height in relation to the width or the Aspect Ratio
  • R indicates Radial Construction
  • 17 indicates the Diameter of the Rim

What’s The Difference Between 265/70r17 and 285/70r17 Tire?

By now you’ve learned the basics of using two tires interchangeably, now let’s see implementing the theory in a real example. Below, we have compared 265/70r17 and 285/70r17 tires in terms of width, aspect ratio, construction materials, and rim diameter.

Width

If you measure from one sidewall to the other sidewall of a tire, you will get the width. It is expressed in millimeters. You can instantly learn the Width of a tire just by looking at the tire size index.

The first three digits of a tire size index indicate the Width of that tire. As you can see, the first three digits of 265/70r17 are 265. It means the width of that tire is 265 millimeters. 

Likewise, the three-digit number of 285/70r17 is 285. It means the Width of that tire is 285 millimeters. So the difference in the Width is 265 – 285 = -20 millimeters.

Now, if you switch to the tire size which is 0 millimeters more or less in Width, it shouldn’t be a problem. 

But you cannot switch tire size depending on Width only. You must consider the Sidewall Height as well. The Sidewall Height depends on Width and Aspect Ratio.

Aspect Ratio

The Aspect Ratio of 265/70r17 is 70, whereas the aspect ratio of 285/70r17 is 70.

So to check the interchangeability of these tires, our sole concern is to analyze how the differences in the aspect ratio impact the other measurements. Let’s start with the simple question first: what is the aspect ratio? And its relation with other measurements.

Aspect Ratio is the ratio of the sidewall from wheel to tread and the width. This measurement is usually represented in a percentage. 

In our example, 265/70r17 Tire size has a width of 265 with an aspect ratio of 70%. So the sidewall height will be 265 x 0.70 or 7.3 inches or 185.5 mm. You can get the number by simply putting the value on the equation.

Equation: Height of a Sidewall = Aspect Ratio of Tire x Width.

On the other hand, the Sidewall Height of 285/70r17 is 7.9 inches.

Though the aspect ratio of the two tire sizes is identical, there’s a gap between the sidewall heights. And it’s because of the different widths of the tires.

This change affects the value of diameter, circumference, and the total number of revolutions per mile.

Construction Type

The tire size index informs you about the Construction Type of a tire. It is expressed by a letter in the tire size index. 

Both 265/70r17 and 285/70r17 have the same letter ‘R’. So, both the tires have Radial Construction in terms of construction type.

Such tires have a sophisticated construction with square footprints on the top. The Radial tires are ideal for driving on-road. 

They are resistant to heat and water. They are next-gen tires and can provide great fuel efficiency.  

Another famous construction type is Bias Ply. They are also known as Cross-ply. It is expressed by the letter ‘B’ in a tire size index. This type is great for driving off-road.

Rim Diameter

To know which tire size fits your vehicle, you must know the wheel rim size of your vehicle as well as the Rim Diameter of a tire. 

For instance, if your vehicle has a 16-inch wheel rim, you can use the tire which has a 16-inch Rim Diameter.

By looking at a tire size index, you can learn instantly the Rim Diameter of a tire. The last two digits of a tire size index indicate the Rim Diameter. It is measured in inches. 

As you can see, the Rim Diameter of 265/70r17 is 17 inches. Similarly, the Rim Diameter of 285/70r17 is 17 inches.

It means that if your vehicle has a 17-inch wheel rim, you can use both tire sizes. But make sure to use the same size tires for all the wheels.

Can You Interchange Between 265/70r17 and 285/70r17?

Directly speaking, No. You should not interchange them. The differences in overall diameter and sidewall of the two models are saying everything. 285/70r17 is built for normal road conditions. Cars using 265/70, which are 3.5% smaller, are speedy ones and they perform on special tracks or roads. No way they can work in the same way.

Speedometer Difference: Using the current Tire Size 265/70r17 Instead Of the New Tire Size 285/70r17

Look at the Table. It shows differences in speedometer reading and the actual speed at any given time when the current Tire Size is 265/70r17 instead of 285/70r17. 

Speedo ReadingActual Speed
20 mph (32.19 km/h)20.7 mph (33.31 km/h)
25 mph (40.23 km/h)25.87 mph (41.64 km/h)
30 mph (48.28 km/h)31.05 mph (49.96 km/h)
35 mph (56.33 km/h)36.22 mph (58.29 km/h)
40 mph (64.37 km/h)41.4 mph (66.62 km/h)
45 mph (72.42 km/h)46.57 mph (74.95 km/h)

Speedometer Difference: Using current Tire Size 285/70r17 Instead Of New Tire Size 265/70r17

The table shows the differences in speedometer reading and the actual speed at any given time when the current Tire Size is 285/70r17 instead of 265/70r17.

Speedo ReadingActual Speed
20 mph (32.19 km/h)19.33 mph (31.1 km/h)
25 mph (40.23 km/h)24.16 mph (38.88 km/h)
30 mph (48.28 km/h)28.99 mph (46.65 km/h)
35 mph (56.33 km/h)33.82 mph (54.43 km/h)
40 mph (64.37 km/h)38.65 mph (62.2 km/h)
45 mph (72.42 km/h)43.48 mph (69.98 km/h)

What you must consider Before Interchange or Replace Tire? 

There are important things to consider Before replacing or swiping the Tires. You cannot simply replace the 265/70r17 tire with the 285/70r17 tire that is in a different shape.

For Example, if the aspect ratio of the existing tire is 40%, replacing it with a tire that has an aspect ratio of  45% might not be a good option.

Doing so will have a variety of consequences on the car’s overall performance, such as variations in top speed and speedometer.

However, to a certain extent, such as minor changes in the diameter or the sidewall, you can switch Tires. However, this can only be done in compliance with the manufacturers’ recommendations.

Anyway, When replacing the Tire, the simple guideline to follow is that the current tire’s size, load index, and speed rating should all match with the replacement Tire.

Load Index and Speed Index of a Tire 265/70r17 and 285/70r17

The load index refers to the maximum load-bearing capacity, whereas the speed index refers to the Tire’s maximum allowable speed at a full load. These are very crucial stats to know before you decide to interchange tires.

Index information can be found on the sidewall right after the Tire size number. It is a combination of numbers and letters that bear a particular meaning. 

Check The load and speed index. They must be as close as possible to fit precisely. These values change depending on the vehicle’s weight and wheel size. Here is a table that shows various load and speed indexes, so you get the idea.

Load IndexKgSpeed IndexSpeed Limit
65290QUp to 160 Km/h
66300RUp to 170 Km/h
67307SUp to 180 Km/h
68315TUp to 190 Km/h
69325HUp to 210 Km/h

Size of the Tire 

The size of the Tire is another vital piece of information to know to exchange the tires properly. The large number on the sidewall shows the tire size.

For example, the marking 265/70r17 on the sidewall represents the size of the Tire. You can also find it in the user manual, on the sidewall, and in other places such as inside the fuel flap or glove compartment.

What Size Tires Is 265/70r17 in Inches?

265/70r17 tires have a 31.6″ diameter, 10.4″ section width, and 17″ wheel diameter.

The circumference is 99.2,” and they make 638 revolutions per mile. The Sidewall Height of this Tire is 7.3 inches.

What Size Tires Is 285/70r17 in Inches?

285/70r17 tires have a diameter of 32.7″, a section width of 11.2″, and a wheel diameter of 17″. 

The circumference is 102.7,” and they have 617 revolutions per mile. The Sidewall Height of this Tire is 7.9 inches.

Summary

Replacing tires is not a big deal unless you don’t know how to compare different tire types. That’s why we’ve shown you a comparison chart analyzing 265/70r17 vs 285/70r17. Hope we were able to help you make the right decision and do the meat modification of your car.

Related Posts:

Similar Posts