275/60R20 vs 275/65R20 Tire: What’s the Difference?

Changing a vehicle’s tires can be either a necessity or for aesthetics. No matter what, compatible-sized tires should always be used. Otherwise, it may lead you to some troubles.

Considering you are planning to swap your car tire from 275/60R20 to 275/65R20. Then it is recommended to know the facts of the afterward changes in the vehicle’s performance.

That’s why you go through this entire article to get a clear concept about what’s the difference between 275/60r20 and 275/65r20.

275/60R20 vs 275/65R20 Tire: Comparison Table

The primary difference between these two tires is the increment of aspect ratio by 5% only. But this small parameter can be a major contributing factor to changing a vehicle’s overall performance.

275/60R20 TireType275/65R20 Tire
32.99 inches or (838)mmDiameter difference: 1.08 (27.5) 3.3% inches (mm)34.07 inches or (865.5)mm
10.83 inches or (275)mmWidth difference 0 (0) 0% inches (mm)10.83 inches or (275)mm
103.65 inches or (2632.65)mmCircumference difference: 3.4 (86.39) 3.3% inches (mm)107.05 inches (2719.05)mm
6.5 inches or (165)mmSidewall Height difference 0.54 (13.75) 8.3% inches (mm)7.04 inches or (178.75)mm
611.3 RPM (379.84)KmRevolutions per mile difference -19.42 (-12.07) -3.2% (km)591.88 RPM (367.78)Km

When you try to compare the tire size of 275/60R20 with 275/65R20, the increment in the diameter is observed first. It gains 3.3% with no change in the width of the tire.

Besides, with the change of the diameter, an increment of 3.3% in the circumference also occurs. As a result, it is over the limit of the minimum acceptability of the diameter during an exchange of the tires.

Moreover, the sidewall height difference between the tires is observed to increase by 8.3%. Therefore, while cornering at high speed, the pressure on the tire will not be uniform.

No change in the width compared to the wheelbase results in lesser control over the traction and grip on the roads. Therefore, all these combine to lose the average balance of the vehicle.

How to read the tire sizes 275/60r20 and 275/65r20?

There are four parts to the tire size 275/60r20, and each part bears a certain meaning. Before you decide to interchange or replace the Tire, you must learn about them. Here is the explanation of each part of the tire size 275/60r20.

  • 275 indicates the width of the tires in millimeters
  • 60 shows the percentage of height to the width or the Aspect Ratio
  • R indicates Radial Construction
  • 20 indicates the Diameter of the Rim

Doing the Same for Tire Sizes 275/65r20

  • 275 means the width of the tires in millimeters
  • 65 shows the percentage of height to the width or the Aspect Ratio
  • R indicates Radial Construction
  • 20 indicates the Diameter of the Rim

What’s The Difference Between 275/60r20 and 275/65r20 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 275/60r20 and 275/65r20 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 275/60r20 are 275. It means the width of that tire is 275 millimeters. 

Likewise, the three-digit number of 275/65r20 is 275. It means the Width of that tire is 275 millimeters. So the difference in the Width is 275 – 275 = 0 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

As you can see, the only difference between the two Tire sizes is the Aspect Ratio. The aspect ratio of 275/60r20 is 60, whereas the aspect ratio of 275/65r20 is 65. On the other hand, the Width and the Rim Diameter of the two Tire sizes are identical.

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, 275/60r20 Tire size has a width of 275 with an aspect ratio of 60%. So the sidewall height will be 275 x 0.60 or 6.5 inches or 165 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 275/65r20 is 7.0 inches.

Though the Width of the two tire sizes is identical, there’s a gap between the sidewall heights because of the Aspect Ratio.

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 275/60r20 and 275/65r20 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 275/60r20 is 20 inches. Similarly, the Rim Diameter of 275/65r20 is 20 inches.

It means that if your vehicle has a 20-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 275/60R20 vs 275/65r20 Tire

No, the tires are not interchangeable. Because a 5% gain on the aspect ratio of the vehicle results in degrading the performance of the vehicle on the road.

Both diameter and circumference difference is beyond the limiting point which is 3%. Mismatching the speedometer and odometer data can cause cop trouble while driving at high speed on a highway. Because the actual speed will be over the speedometer reading.

Finally, losing stability and balance while driving may occur since the width remains the same.

Speedometer Difference: Using the current Tire Size 275/60r20 Instead Of the New Tire Size 275/65r20

Look at the Table. It shows differences in speedometer reading and the actual speed at any given time when the current Tire Size is 275/60r20 instead of 275/65r20.

Speedo ReadingActual Speed
20 mph (32.19 km/h)20.66 mph (33.24 km/h)
25 mph (40.23 km/h)25.82 mph (41.55 km/h)
30 mph (48.28 km/h)30.98 mph (49.86 km/h)
35 mph (56.33 km/h)36.15 mph (58.18 km/h)
40 mph (64.37 km/h)41.31 mph (66.49 km/h)
45 mph (72.42 km/h)46.48 mph (74.8 km/h)

Speedometer Difference: Using current Tire Size 275/65r20 Instead Of New Tire Size 275/60r20

The table shows the differences in speedometer reading and the actual speed at any given time when the current Tire Size is 275/65r20 instead of 275/60r20.

Speedo ReadingActual Speed
20 mph (32.19 km/h)19.36 mph (31.16 km/h)
25 mph (40.23 km/h)24.21 mph (38.96 km/h)
30 mph (48.28 km/h)29.05 mph (46.75 km/h)
35 mph (56.33 km/h)33.89 mph (54.54 km/h)
40 mph (64.37 km/h)38.73 mph (62.33 km/h)
45 mph (72.42 km/h)43.57 mph (70.12 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 275/60r20 tire with the 275/65r20 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 various 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 275/60r20 and 275/65r20

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. 

Here is an example of how the index information is usually written on the sidewall: 275/60r20 90A. The 90A stands for load and speed index, with 90 indicating a maximum load-bearing capacity of 600 kg, whereas ‘A’ denotes an allowed speed of up to 170 km/h.

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 275/60r20 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 275/60r20 in Inches?

275/60r20 tires have a 33.0″ diameter, 10.8″ section width, and 20″ wheel diameter.

The circumference is 103.6″ and they make 612 revolutions per mile. The Sidewall Height of this Tire is 6.5 inches.

What Size Tires Is 275/65r20 in Inches?

275/65r20 tires have a diameter of 34.1″, a section width of 10.8″, and a wheel diameter of 20″.

The circumference is 107.0″ and they have 592 revolutions per mile. The Sidewall Height of this Tire is 7.0 inches.

Conclusion

Upsizing your tire over the limit can be exciting as it enhances the vehicle’s aesthetics. But it may come with a lot of negative feedback to you and your vehicle. 

This article presents the facts and comparison between the 275/60R20 with  275/65R20 tires. Now you can use your judgment and decide whether to swap and upsize your tire or not.

Related Posts:

Similar Posts