Tires are available in many sizes and not all tires are the same. Choosing the right tire for your vehicle is crucial and the numbers on each tire can be confusing.

Keep reading to learn more about the difference between 235 and 245 tires. 

Difference Between 235 And 245 Tires

The number 235 and 245 refers to the measured cross-section width of the tire in millimeters. For example, if your tire size is 235/75R/18, it means that the tire measures 235 millimeters across the tire from sidewall to sidewall. This is the width of the tire.

If you have a 245/75R/18 tire, it means that the tire measures 245 millimeters across the tire from sidewall to sidewall. It is 10 millimeters wider than the 235 tire size. 

tire size comparison

What do the other tire numbers mean?

There are other numbers on a tire that are important to know. Let’s use a tire size of P235/75R/18 as an example.

  • P = A prefix put on the tire which means passenger car tire.
  • 235 = The width of the tire measured in millimeters.
  • 75 = The aspect ratio of the tire. It’s the height of the sidewall measured as a percentage from the wheel rim to the top of the tread. In this case, 75 means 75%.
  • R = The construction used in the tire casing. R means radial construction.
  • 18 = The diameter of the tire measured in inches.
4 car tires

Can a 235 tire be changed with a 245 tire?

Putting the wrong sized tire on your car can be dangerous and you should only use the manufacturers’ recommended tire size.

However, it is possible to use a different tire size under certain circumstances and if you change all four tires at the same time. 

In this example, yes it is possible for a 235 tire to be changed with a 245 tire if your vehicle is suitable for the change. 

The 245 tire will be slightly larger than the 235 tire and depending on the vehicle, there may not be enough room to safely fit a larger tire. 

This is more noticeable in newer vehicles whereas older vehicles generally have more space to fit a larger tire.

You may notice the vehicle will handle slightly different and the speedometer may not be 100% accurate. 

Other tire sizes are often interchangeable, always confirm what tire sizes are suitable for your vehicle before making a change.

changing a car tire

Other differences between a 235 and 245 tire

Other than the size difference, there are a few other noticeable differences between a 235 and 245 tire. 

Rolling resistance

The 235 tire size has a lower rolling resistance with the ground and therefore this tire will give you better fuel economy than the 245 tire size.

tire on road resistance

Speedometer

When your vehicle was new, the speedometer was calibrated to work in conjunction with the tire size that is originally on the car. 

When you change the tire size, the speedometer will no longer be properly calibrated and will show an inaccurate reading. 

The difference is usually only around 2% but it’s possible to show a speed that is slower than you are actually going. 

The 245 size tire could cause the actual speed to be lower than the 235 size tire. 

vehicle speedometer

Cost

Not always the case, but in general, a larger tire will cost more than a smaller tire. In this case, a 245 tire would cost more than a 235 tire. 

Better handling

Normally wider tires will perform better with respect to vehicle handling. A 245 tire size will handle better than a 235 tire size.

car on a sharp turn

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