Tire Size 275/65r18 vs 275/70r18

Fitment Guide

The diameter difference between 275/65R18 and 275/70R18 tires is 3.4%, which slightly exceeds the recommended 3% range. While this interchange may still be possible, it’s essential to consider potential fitment issues and make necessary adaptations to prevent rubbing or clearance problems.

On-Road Impact

Switching to a larger tire size can have various effects on your vehicle’s on-road performance. Let’s explore some of the key aspects to consider:

• Speedometer Accuracy: With the larger tire size, your speedometer reading will be slightly off. At a reading of 20 mph (32.19 km/h), your actual speed will be 20.68 mph (33.27 km/h). This difference is relatively small and may not be noticeable in everyday driving.
• Ride Comfort: The taller sidewall of the 275/70R18 tire can provide a slightly softer ride, as the increased air volume helps absorb road imperfections more effectively. However, this difference may be subtle and depends on various factors, such as tire construction and vehicle suspension.
• Fuel Efficiency: The larger tire size may slightly impact your vehicle’s fuel efficiency due to the increased rolling resistance. However, this difference is likely to be minimal and may not be noticeable in real-world driving conditions.

Off-Road Impact

If you frequently take your vehicle off-road, switching to a larger tire size can offer several benefits:

• Ground Clearance: The taller sidewall of the 275/70R18 tire provides an additional 0.54 inches (13.75 mm) of ground clearance, which can be beneficial when navigating rough terrain, obstacles, or deep ruts.
• Traction: The larger tire size can provide a slightly larger contact patch, potentially improving traction in loose or slippery conditions. However, the actual impact on traction depends on various factors, such as tire tread design and vehicle weight distribution.
• Durability: The taller sidewall of the 275/70R18 tire offers more protection against punctures and damage from rocks or other off-road hazards. This can help improve the overall durability of your tires in challenging off-road conditions.

What is the Difference Between 275/65R18 and 275/70R18?

The primary difference between the 275/65R18 and 275/70R18 tire sizes lies in the sidewall height. The 275/70R18 tire has a sidewall that is 0.54 inches (13.75 mm) taller than the 275/65R18 tire, which equates to a 7.7% increase in sidewall height.

This difference in sidewall height contributes to the overall diameter difference of 1.08 inches (27.5 mm) or 3.4% between the two tire sizes, with the 275/70R18 being the larger tire.

Can I Use 275/70R18 Instead of 275/65R18?

While it is possible to use a 275/70R18 tire instead of a 275/65R18, it is not recommended without careful consideration. The difference in overall diameter between the two sizes is 3.4%, which slightly exceeds the generally accepted guideline of staying within a 3% difference when changing tire sizes.

Exceeding this threshold may lead to potential issues such as inaccurate speedometer readings, altered vehicle handling, and possible clearance problems. It is advisable to consult with a professional and ensure that the new tire size is compatible with your vehicle before making the switch.

How Much Taller Is a 275/70R18 Tire Than a 275/65R18?

A 275/70R18 tire is 1.08 inches (27.5 mm) taller than a 275/65R18 tire. This difference in height is due to the increased sidewall height of the 275/70R18 tire, which is 0.54 inches (13.75 mm) taller than that of the 275/65R18 tire.

The overall diameter of the 275/70R18 tire is 33.16 inches (842.2 mm), while the 275/65R18 tire has a diameter of 32.07 inches (814.7 mm), resulting in a difference of 1.08 inches (27.5 mm) or 3.4%.

Our Observations

While switching from 275/65R18 to 275/70R18 tires can offer some benefits, particularly for off-road use, it’s essential to consider the potential drawbacks as well.

The 3.4% diameter difference slightly exceeds the recommended 3% range, which may necessitate adaptations to prevent fitment issues.

On-road, the impact on speedometer accuracy, ride comfort, and fuel efficiency is likely to be minimal and may not be noticeable in everyday driving.

Off-road, the increased ground clearance and potential improvements in traction and durability can be advantageous. Ultimately, the decision to switch tire sizes should be based on your specific needs, preferences, and vehicle setup.