A great advantage of knowing the tire size index is that you can tell whether a tire is going to fit your vehicle or not just by looking at the sidewall. But first, you have to know what the tire size index is.
A tire size index is a combination of numbers and letters, indicating several aspects of the tire so that manufacturers and car owners can understand which tire is perfect for their vehicles. But don’t be sad if you are hearing about the tire size index for the first time. We are here to help you.
Because in this article, we will be showing a comprehensive differentiation between the 265 70R17 and 285 70R17 tires in an innovative way to cover everything.
265/70R17 vs 285/70R17: What is the Big Difference?
Before beginning the comparison between 265/70R17 and 285/70R17, we want you to take a look at 285/70R17 vs 285/75R17 to know more about the tire size index.
The difference between 265/70R17 and 285/70R17 will be taken apart into 4 sections. Because the tire size index consists of these 4 parts. For instance, breaking down 265/70R17, we will get –
- 265 stands for – Tire width in meters
- 70 stands for – The aspect ratio of height/width
- R stands for – Construction type
- 17 stands for – Rim diameter in inches
It is the first digit of the tire size index. The tire manufacturers measure the width of the tires very carefully from one sidewall to the other. And what is written in the index is 100% accurate. So, there’s no need to doubt. And the width is normally expressed in millimeters.
By looking at the first digits of both 265 70R17 and 285 70R17, we can notice a difference. The first digit of tire 265 70R17 is 265 whereas the first digit of the other one is 285. So, there is a difference of 285 – 265 = 20 millimeters in their widths. This difference has a great impact on tire compatibility.
When there is a big difference in the width, you may not need to find any other difference. Still, we will continue this comparison for other aspects. The second digit of the tire size index refers to the aspect ratio. The tire manufacturers distribute aspect ratios in percent. So, when you find a tire having an aspect ratio of 70, it means the height of the tire is 70% of the width.
As you can see, both 265/70R17 and 285/70R17 have the same second digit, which is 70. Therefore, their aspect ratio is the same. To calculate the aspect ratio of a tire, you can divide the height with the cross-sectional width and multiply by 100. The equation goes –
Aspect Ratio of Tire = Height/Width x 100%
The construction type explains how the tire was assembled and its handling characteristics. When you see the letter ‘R’ marked in the tire size index, it stands for “Radial Construction”. It suggests that the tire is a radial type, having a sophisticated construction. It also indicates there is a 90-degree angle in the tire cords from one bead to another.
With that being said, there can be another letter ‘B’ often seen in tire size indexes. This indicates the tire is a bias ply type having a different construction. Both 265/70R17 and 285/70R17 have the same letter ‘R’. Hence, there is no difference in their construction type.
It’s very easy to find the rim diameter as it is the center hole of the tire where the rim goes in. The very last digit of the tire size index represents the rim diameter. Measuring from one open bead to the opposite one, you can find the rim diameter of the tire and it is expressed in inches.
Considering the rim diameters of both 265/70R17 and 285/70R17, we find the same digit 17. It means both tires have a rim diameter of 17 inches. So, there is no difference either.
We Want to Wrap Things Up with a Comparison Chart: Tire Size 265/70R17 vs 285/70R17
We have presented a comparison table for those who don’t have much time to read the whole article yet want to know the difference between 265 70R17 and 285 70R17.
|Section width||10.4 inch||11.2 inch||+0.8 inch (+7.5%)|
|Overall diameter||31.6 inch||32.7 inch||+1.1 inch (+3.5%)|
|Circumference||99.3 inch||102.8 inch||+3.5 inch (+3.5%)|
|Revs per km||638.1||616.6||-21.5 (-3.4%)|
|Sidewall height||7.3 inch||7.9 inch||+0.6 inch (+7.5%)|
|Aspect Ratio||70||70||0 (0%)|
By looking at the 265/70R17 vs 285/70R17 comparison chart, we find differences in every aspect. All these differences make a change in the ground clearance to 0.6 inches. And the diameter changes to 3.5%, which is greater than 3%. As a result, it would be risky to have one pair of 265/70R17 and another pair of 285/70R17.
To find the difference between 265/70R17 and 285/70R17 in terms of front and sideways, take a look at these pictures –
Reading this article, you should definitely understand both the difference between 265/70R17 and 285/70R17 along with what tire size index elongates. So, you are now aware that a change in the width is not good for changing tires.
All the tires of your vehicle must have the same width. It is important for turning and while you are driving off-road. However, you know better what is good for your vehicle. We believe you will make a smart decision to change from 265/70R17 to 285/70R17 after reading this article.