Tire Size 275/70r18 vs 285/75r18
Changing your vehicle’s tire size can affect various aspects of its performance, from handling and fuel efficiency to aesthetics and comfort. Here are the top 5 key points of switching from 275/70r18 to 285/75r18 tires
- 1.67-inch taller size improves ground clearance for off-road use
- Wider 285mm section enhances traction with a larger contact patch
- Speedometer will read about 5% lower than actual speed
- Taller sidewalls slightly improve ride comfort on rough terrain
- Minor reduction in fuel efficiency due to increased rolling resistance
275/70r18 vs 285/75r18 Table
The main difference between 275/70R18 and 285/75R18 tires is the overall diameter. 285/75R18 tires have a diameter that is 1.67 inches (42.5 mm) larger than 275/70R18 tires, which equates to a 5% difference.
Fitment Guide
It’s essential to stay within the recommended 3% difference in overall diameter. In this case, the 5% difference between the 275/70r18 and 285/75r18 tires exceeds this guideline. As a result, making this change may require modifications to your vehicle to prevent rubbing or clearance issues and its not recommended.
On-Road Impact
Switching to a taller tire size can have various effects on your vehicle’s on-road performance. Here are some key areas to consider:
- Speedometer Accuracy: Due to the larger tire diameter, your speedometer will read slower than your actual speed. At 20 mph, your true speed will be 21.01 mph, which can be significant over long distances.
- Fuel Economy: Larger tires can negatively impact your gas mileage due to increased rolling resistance and weight. The 285/75r18 tires have a 5% larger circumference, which means your engine will have to work harder to maintain the same speed.
- Handling: The taller sidewall of the 285/75r18 tires (8.42 inches compared to 7.58 inches) can lead to a slightly softer ride but may also result in increased body roll during cornering.
- Braking Distance: The larger tire size may increase your braking distance, especially in wet conditions, due to the reduced contact patch area relative to the tire’s size.
Off-Road Impact
If you frequently take your vehicle off-road, the switch to 285/75r18 tires can offer some advantages:
- Ground Clearance: The taller tire size will increase your vehicle’s ground clearance by approximately 0.84 inches (21.25 mm), which can be beneficial when navigating rough terrain or obstacles.
- Traction: The wider tread of the 285/75r18 tires (11.22 inches compared to 10.83 inches) can provide better traction in loose or slippery conditions, such as mud, sand, or snow.
- Durability: Larger tires generally have thicker sidewalls, which can offer increased protection against punctures and damage from rocks or debris.
What Does 275/70r18 Tire Mean?
This size is ideal for those who want to balance speed and traction. The “275” in 275 70r18 refers to the tire’s width in millimeters.
The “70” is the aspect ratio, which tells you how tall the sidewall is concerning the width. The “r” stands for radial, and the “18” is the diameter of the wheel in inches. The tire size 275/70r18 is equal to 33.2×10.8R18 in inches.
What Does 285/75r18 Tire Mean?
The tire size 285/75r18 is a radial tire designed to fit 18-inch diameter wheels. It has a width of 285mm, which is approximately 11.2 inches.
The tire’s aspect ratio is 75%, meaning the sidewall height is 75% of the tire’s width. The tire size 285/75r18 is equal to 34.8×11.2R18 in inches.
Can I Use 275/70r18 Instead of 285/75r18?
No, using 275/70r18 instead of 285/75r18 results in a 5% increase in diameter, exceeding the recommended 3% limit. It’s not advised as it may affect speedometer accuracy and handling.
How Much Taller Is A 285/75r18 Tire Than A 275/70r18?
The 285/75r18 tire is 1.67 inches (42.5 mm) taller than the 275/70r18 tire, representing a 5% increase in diameter.
The height of a 285/75R18 tire is 34.83 inches or 884.7mm, while a 275/70R18 tire has a height of 33.16 inches or 842.2mm.
How Much Wider Is A 285/75r18 Tire Than A 275/70r18?
The 285/75R18 tire is 0.39 inches (10 mm) wider than the 275/70R18 tire, which represents a 3.6% increase in width.
The width of a 285/75r18 tire is 11.22 inches or 285mm, while a 275/70r18 tire has a width of 10.83 inches or 275mm.
What Size Rim For 285/75R18?
The recommended rim size for a 285/75r18 tire is typically an 18-inch diameter rim. The ideal rim width for a 285/75r18 tire is typically in the range of 7.5 to 9.5 inches. Therefore, a rim with an 18-inch diameter would be suitable for mounting a 285/75R18 tire.
What Size Rim For 275/70R18?
Typically, a 275/70R18 tire is best used with an 18-inch diameter rim. For optimal performance, the ideal rim width for this tire size ranges from 7 to 9 inches. Therefore, an 18-inch diameter rim would be suitable for mounting a 275/70R18 tire.
Our Observations
After analyzing the differences between 275/70r18 and 285/75r18 tires, we’ve found that the impact of switching sizes depends on your driving habits and priorities. The 5% increase in overall diameter is significant and can lead to rubbing or clearance issues if your vehicle isn’t properly modified.
On-road, you may experience reduced fuel economy, softer handling, and slightly inaccurate speedometer readings. However, off-road enthusiasts may appreciate the increased ground clearance and traction provided by the larger tires.
Ultimately, the decision to switch tire sizes should be based on your specific needs and driving conditions, as well as a thorough understanding of the potential trade-offs involved.
Meet Caitlin McCormack, a Tire Size Expert and Blogger Passionate About Everything Related to Tires. With Years of Experience in the Tire Industry, Caitlin Has Become an Expert in Tire Sizes and Their Impact on Vehicle Performance.