155/70r13 vs 145/80r13 Tire: What’s the Difference?

Choosing the right set of interchangeable tires for your vehicle is a hectic situation requiring rational thinking and risky decisions. 

Even the smallest of variations within the factors can prove to be a significant drawback. Not only will it not show its optimum performance, but even the comfort it previously provided could also be endangered. 

This article will cover the comparison between 155/70r13 Vs 145/80r13 tires. Keep reading to learn the difference between the two tiers and then decide whether the interchange is worth all the hassle or not.

155/70r13 vs 145/80r13 Tire: Comparison Table

If you are going to make big decisions having the right data is vital. Below, we have displayed the comparison table between the two tires. The statistics have been compiled from TacomaWorld, which can be relied on.

155/70r13 TireType145/80r13 Tire
21.54 Inches or 547.2 mmDiameter Difference 0.59(15) 2.7 inches (mm)22.13 inches or 562.2 mm
6.1 inches or  155 mmWidth Difference -0.39(-10)-6.5 inches (mm)5.71 inches 145 mm
67.68 inches or 1718.08 mmCircumference Difference1.86(47.12) 2.7 inches (mm)69.54 inches or 1766.2 mm
4.17  inches or 108.5 mmSidewall Height Difference 0.3(7.5) 6.9 inches (mm)4.7 inches or 116 mm
936.17 RPM or 581.71 KMRevolutions Difference -24.98(-15.52) -2.7 per mile (km)91.19  RPM or 566.19 KM

The percentage difference in the diameter and the circumference for both of these tires are 2.7, albeit negative. As such, these are clearly in the safe zone in the compatibility margin. 

On the other hand, the percentage difference in width is 6.5 percent, while the percentage difference in the sidewall is 6.9 percent. 

These factors are well above the 3 percent margin, with the second one smaller than the first one in terms of sidewall height.

Finally, when it comes to the revolutions per mile, the percentage difference is -2.7 percent. Based on these statistics, we can say that the difference in revolutions between the wheels is relatively insignificant.

How to read the tire sizes 155/70r13 and 145/80r13?

There are four parts to the tire size 155/70r13, 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 155/70r13.

  • 155 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
  • 13 indicates the Diameter of the Rim

Doing the Same for Tire Sizes 145/80r13

  • 145 indicates the width of the tires in millimeters
  • 80 indicates the percentage of height in relation to the width or the Aspect Ratio
  • R indicates Radial Construction
  • 13 indicates the Diameter of the Rim

What’s The Difference Between 155/70r13 and 145/80r13 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 155/70r13 and 145/80r13 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 155/70r13 are 155. It means the width of that tire is 155 millimeters. 

Likewise, the three-digit number of 145/80r13 is 145. It means the Width of that tire is 145 millimeters. So the difference in the Width is 145 – 155 = -10 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

There’s a difference between the Aspect Ratio of the two tire sizes. The Aspect Ratio of 155/70r13 is 70, whereas the aspect ratio of 145/80r13 is 80.

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, 155/70r13 Tire size has a width of 155 with an aspect ratio of 70%. So the sidewall height will be 155 x 0.70 or 4.2 inches or 108.5 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 145/80r13 is 4.6 inches. Due to the difference in the Aspect Ratio, the sidewall heights of the two tire sizes are different.

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 155/70r13 and 145/80r13 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 155/70r13 is 13 inches. Similarly, the Rim Diameter of 145/80r13 is 13 inches.

It means that if your vehicle has a 13-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 155/70r13 vs 145/80r13 Tire

No, these two tires aren’t safe for interchanging. This is because it is not compatible with all categories and variables. 

Note that certain factors are compatible, and some can be neglected if the percentage isn’t too high. However, the percentage difference in sidewall height and width is incredibly significant. 

As such, we can conclude the fact that we cannot interchange these tires at any time.

Speedometer Difference: Using the current Tire Size 155/70r13 Instead Of the New Tire Size 145/80r13

Look at the Table. It shows differences in speedometer reading and the actual speed at any given time when the current Tire Size is 155/70r13 instead of 145/80r13. 

Speedo ReadingActual Speed
20 mph (32.19 km/h)20.55 mph (33.07 km/h)
25 mph (40.23 km/h)25.69 mph (41.34 km/h)
30 mph (48.28 km/h)30.82 mph (49.6 km/h)
35 mph (56.33 km/h)35.96 mph (57.87 km/h)
40 mph (64.37 km/h)41.1 mph (66.14 km/h)
45 mph (72.42 km/h)46.23 mph (74.41 km/h)

Speedometer Difference: Using current Tire Size 145/80r13 Instead Of New Tire Size 155/70r13

The table shows the differences in speedometer reading and the actual speed at any given time when the current Tire Size is 145/80r13 instead of 155/70r13.

Speedo ReadingActual Speed
20 mph (32.19 km/h)19.47 mph (31.33 km/h)
25 mph (40.23 km/h)24.33 mph (39.16 km/h)
30 mph (48.28 km/h)29.2 mph (46.99 km/h)
35 mph (56.33 km/h)34.07 mph (54.82 km/h)
40 mph (64.37 km/h)38.93 mph (62.66 km/h)
45 mph (72.42 km/h)43.8 mph (70.49 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 155/70r13 tire with the 145/80r13 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 155/70r13 and 145/80r13

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: 155/70r13 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 155/70r13 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 155/70r13 in Inches?

155/70r13 tires have a 21.5″ diameter, 6.1″ section width, and 13″ wheel diameter.

The circumference is 67.6″ and they make 937 revolutions per mile. The Sidewall Height of this Tire is 4.2 inches.

What Size Tires Is 145/80r13 in Inches?

145/80r13 tires have a diameter of 22.1″, a section width of 5.7″, and a wheel diameter of 13″. 

The circumference is 69.5″ and they have 912 revolutions per mile. The Sidewall Height of this Tire is 4.6 inches.

Conclusion

To end things with, we must advise you never to use tires that have factors with a compatibility rate above 3 percent.

Suppose that you will look for the right pair of interchangeable tires that can work to be alternative options for each other. In that case, you should seek a professional’s help.  

Only they would be able to say which one pair is the decent choice for your vehicle based on your requirements. If you get the wrong set of tires, you might have to regret this later on!

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