Tire Size 285/70r17 vs 275/70r18
Are you considering switching from 285/70R17 to 275/70R18 tires? We’ll explore the key differences between these two tire sizes and help you make an informed decision.
- The 1.4% difference in diameter is within the acceptable range
- Minimally improve ride comfort and gas mileage
- Speedometer accuracy difference is negligible
- Provide a small increase in ground clearance for off-road use
- Marginally better traction and durability off-road
285/70r17 vs 275/70r18 Table
The main difference between 285/70R17 and 275/70R18 tires is the diameter.
Fitment Guide
It’s crucial to ensure that the diameter difference falls within the acceptable range of plus or minus 3%. In this case, the 1.4% difference between the 285/70R17 and 275/70R18 tires is within the acceptable range, making the switch possible without requiring any adaptations.
On-Road Impact
Switching to 275/70R18 tires can have several effects on your vehicle’s on-road performance. Let’s explore some of the key aspects:
- Speedometer Accuracy: Due to the larger diameter of the 275/70R18 tires, your speedometer may read slightly lower than your actual speed. At 20 mph (32.19 km/h), your actual speed would be 20.27 mph (32.63 km/h), a difference of 0.27 mph (0.44 km/h). While this difference is negligible, it’s important to be aware of it.
- Ride Comfort: The slightly taller sidewall of the 275/70R18 tires may provide a marginally smoother ride compared to the 285/70R17 tires. However, the difference in sidewall height is only 0.28 inches (7 mm), so the impact on ride comfort may not be significant.
- Gas Mileage: The larger diameter of the 275/70R18 tires means that your vehicle will have fewer revolutions per mile (608.25) compared to the 285/70R17 tires (616.6). This difference of 8.35 revolutions per mile (5.19 per km) translates to a 1.4% reduction in revolutions, which may slightly improve your gas mileage.
Off-Road Impact
If you frequently take your vehicle off-road, switching to 275/70R18 tires can have some benefits and drawbacks:
- Ground Clearance: The taller sidewall of the 275/70R18 tires can provide a small increase in ground clearance, which may be beneficial when navigating rough terrain. However, the difference of 0.28 inches (7 mm) is relatively small and may not have a significant impact on overall off-road performance.
- Durability & Wear: The wider tread of the 285/70R17 tires (11.22 inches or 285 mm) compared to the 275/70R18 tires (10.83 inches or 275 mm) may provide slightly better traction and durability in off-road conditions. However, the difference of 0.39 inches (10 mm) is not substantial and may not be noticeable in most situations.
What is the Difference Between 285/70R17 and 275/70R18?
The main difference between 285/70R17 and 275/70R18 tires is the diameter. The 275/70R18 tire has a diameter of 33.16 inches (842.2 mm), which is 0.45 inches (11.4 mm) larger than the 285/70R17 tire’s diameter of 32.71 inches (830.8 mm).
Can I Use 275/70R18 Instead of 285/70R17?
Yes, you can use 275/70R18 tires instead of 285/70R17 tires. The difference in diameter between these two sizes is only 1.4%, which is within the acceptable range of 3%.
This means that switching to 275/70R18 tires should not significantly affect your vehicle’s performance, handling, or safety.
How Much Taller Is a 275/70R18 Tire Than a 285/70R17?
A 275/70R18 tire is 0.45 inches (11.4 mm) taller than a 285/70R17 tire. The overall diameter of the 275/70R18 tire is 33.16 inches (842.2 mm), while the overall diameter of the 285/70R17 tire is 32.71 inches (830.8 mm).
How Much Wider is a 285/70R17 Tire Than a 275/70R18?
A 285/70R17 tire is 0.39 inches (10 mm) wider than a 275/70R18 tire. The width of the 285/70R17 tire is 11.22 inches (285 mm), whereas the width of the 275/70R18 tire is 10.83 inches (275 mm).
Our Observations
After analyzing the differences between 285/70R17 and 275/70R18 tires, we can conclude that the impact of switching between these two sizes is relatively minor. The 1.4% difference in diameter falls within the acceptable range, meaning that the switch can be made without requiring any adaptations to your vehicle.
On the road, the slightly larger diameter of the 275/70R18 tires may result in a minimally smoother ride and a small improvement in gas mileage. However, the difference in speedometer accuracy is negligible and should not cause any concerns.
For off-road use, the taller sidewall of the 275/70R18 tires may provide a small increase in ground clearance, but the difference is not significant enough to greatly impact overall performance. The wider tread of the 285/70R17 tires may offer marginally better traction and durability, but again, the difference is minimal.
Ultimately, the decision to switch from 285/70R17 to 275/70R18 tires comes down to personal preference and specific driving needs. While the differences between these two sizes are not substantial, it’s always important to consider factors such as vehicle manufacturer recommendations, load capacity, and speed rating when selecting new tires.
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.