Tire Size 285/65r18 vs 285/70r18
Changing tire sizes, even when the width remains the same, can lead to noticeable differences in ride height, speedometer accuracy, and overall performance. Let’s examine what happens when you switch from 285/65r18 to 285/70r18 tires.
- Increased ground clearance for better off-road capability
- Slightly softer ride due to taller sidewall
- Speedometer will read slower than actual speed
- Minor decrease in fuel efficiency from higher rolling resistance
- Enhanced rugged aesthetics for a more aggressive look
285/65r18 vs 285/70r18
Fitment Guide
In this case, switching from 285/65r18 to 285/70r18 results in a diameter difference of 3.4%, exceeding the 3% guideline.
This means the interchange is not recommended without making necessary adjustments to prevent rubbing or clearance issues.
On-Road Impact
Switching to taller 285/70r18 tires can have various effects on your vehicle’s on-road performance. Here are some key areas to consider:
- Ground Clearance: The taller sidewall of the 285/70r18 tires will raise your vehicle’s ground clearance by approximately 0.56 inches (14.25 mm). This can be beneficial for avoiding obstacles and navigating rough roads.
- Ride Comfort: The increased sidewall height of the 285/70r18 tires may provide a slightly softer and more compliant ride compared to the 285/65r18 tires. However, the difference may be subtle and not noticeable to all drivers.
- Speedometer Accuracy: Due to the larger overall diameter, your vehicle’s speedometer will read slower than your actual speed when using 285/70r18 tires. At 20 mph (32.19 km/h), your actual speed would be 20.69 mph (33.3 km/h), a difference of 0.69 mph (1.11 km/h). Keep this in mind to avoid unintentionally exceeding speed limits.
- Fuel Efficiency: The taller 285/70r18 tires will have a slightly higher rolling resistance, which may result in a minor decrease in fuel efficiency compared to the 285/65r18 tires. However, the difference is likely to be negligible in real-world driving conditions.
Off-Road Impact
If you frequently take your vehicle off-road, the switch to 285/70r18 tires can offer some advantages:
- Increased Traction: The taller sidewall of the 285/70r18 tires allows for a larger contact patch with the ground, providing improved traction on loose surfaces like sand, gravel, or mud.
- Better Obstacle Clearance: With an additional 0.56 inches (14.25 mm) of ground clearance, the 285/70r18 tires can help your vehicle navigate over rocks, roots, and other obstacles more easily, reducing the risk of damage to the undercarriage.
- Enhanced Aesthetics: For those who appreciate a more rugged and aggressive look, the taller 285/70r18 tires can give your vehicle a more imposing stance and improved visual proportions, particularly on lifted or modified vehicles.
What is the Main Difference Between 285/65r18 and 285/70r18?
The main difference between 285/65r18 and 285/70r18 tires is the sidewall height. The 285/70r18 tires have a 0.56-inch (14.25 mm) taller sidewall compared to the 285/65r18 tires.
Can I Use 285/70r18 Instead of 285/65r18?
Using 285/70r18 tires instead of 285/65r18 is not recommended without adjustments, as the diameter difference exceeds the 3% guideline. It may cause rubbing or clearance issues.
How Much Taller Is a 285/70r18 Tire Than a 285/65r18?
A 285/70r18 tire is 1.12 inches (28.5 mm) taller in overall diameter than a 285/65r18 tire, with the sidewall height being 0.56 inches (14.25 mm) taller.
Our Observation
While switching from 285/65r18 to 285/70r18 tires offers some benefits, particularly for off-road use, it’s essential to consider the potential drawbacks.
The 3.4% difference in overall diameter exceeds the recommended 3% threshold, which may result in rubbing or clearance issues if proper adjustments aren’t made.
On-road, the differences in ride quality, fuel efficiency, and speedometer accuracy are likely to be minimal and may not be noticeable to most drivers. However, the increased ground clearance and tire weight can slightly affect handling and braking performance.
Off-road, the taller sidewall of the 285/70r18 tires can provide improved traction, obstacle clearance, and a more aggressive appearance. These benefits may be more pronounced and appreciated by drivers who frequently tackle challenging terrain.
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.