Tire Size 305/70r17 vs 285/70r17
Tire size changes can significantly impact your vehicle’s performance and safety. This article explores the effects of switching from 305/70R17 to 285/70R17 tires, examining both on-road and off-road implications.
- The width decreases by 0.79 inches, potentially improving fuel efficiency
- Overall diameter changes only 0.3%, maintaining speedometer accuracy
- Sidewall height reduces by 0.55 inches, slightly firming up the ride
- Narrower tires may offer better performance in snow and mud
- The change is within safe limits and doesn’t require vehicle modifications
305/70r17 vs 285/70r17 Table
The primary difference between 305/70R17 and 285/70R17 tires is width. The 285/70R17 is 20mm (0.79 inches) narrower than the 305/70R17.
Fitment Guide
In this case, the diameter difference is only -0.3%, which is well within the acceptable range. This means the switch from 305/70R17 to 285/70R17 is considered safe and doesn’t require significant modifications to your vehicle.
On-Road Impact
The change from 305/70R17 to 285/70R17 tires will have some noticeable effects on your vehicle’s on-road performance. Let’s examine these impacts in detail:
- Handling: The narrower 285/70R17 tires may offer slightly less grip in dry conditions due to a smaller contact patch. However, this difference is relatively minor and may not be noticeable in everyday driving.
- Ride Comfort: With a slightly shorter sidewall (7.85 inches vs. 8.41 inches), the 285/70R17 tires might provide a marginally firmer ride. The difference is small, though, and most drivers won’t notice a significant change in comfort.
- Gas Mileage: The narrower profile of the 285/70R17 tires could potentially improve fuel efficiency due to reduced rolling resistance. However, the improvement is likely to be minimal, perhaps 1-2% at most.
- Speedometer Accuracy: The -0.3% difference in diameter means your speedometer will be only slightly affected. At 20 mph, the actual speed will be 19.94 mph – a negligible difference that won’t significantly impact your driving or legal compliance.
- Aesthetics: The 285/70R17 tires will appear slightly narrower on your vehicle. This might give a less aggressive look compared to the wider 305/70R17 tires, but the overall appearance change will be subtle.
Off-Road Impact
For off-road enthusiasts, the switch to 285/70R17 tires will have some implications worth considering:
- Traction: The narrower 285/70R17 tires may provide better performance in mud and snow due to higher ground pressure. However, they might offer slightly less flotation in sand compared to the wider 305/70R17 tires.
- Ground Clearance: With only a 2.6mm (0.1 inch) decrease in diameter, the impact on ground clearance is negligible. This small difference won’t significantly affect your vehicle’s ability to clear obstacles on the trail.
- Maneuverability: The narrower tires might offer a slight advantage in tight off-road situations, allowing for easier steering and less resistance when turning in challenging terrain.
- Durability: Both tire sizes are designed for off-road use, but the slightly shorter sidewall of the 285/70R17 might be marginally more resistant to punctures from rocks and other sharp objects.
What is the Difference Between 305/70r16 and 285/70r17?
The main difference between 305/70r16 and 285/70r17 tires is their width. The 305/70r16 is significantly wider at 12.01 inches (305mm) compared to the 285/70r17, which is 11.22 inches (285mm) wide.
This 0.79-inch (20mm) difference in width is the most noticeable change, affecting the tire’s footprint, handling characteristics, and appearance on the vehicle.
Can I Use 285/70r17 Instead of 305/70r16?
Yes, you can use 285/70r17 instead of 305/70r16. The diameter difference is only -0.3%, well within the recommended 3% limit for safe tire swaps.
This change won’t significantly affect your vehicle’s performance or require major modifications.
How Much Taller Is a 305/70r16 Tire Than a 285/70r17?
The 305/70r16 tire is only slightly taller than the 285/70r17. The difference in height is 0.1 inches (2.6mm), with the 305/70r16 having a diameter of 32.81 inches compared to the 285/70r17’s 32.71 inches.
This minimal height difference (0.3%) is negligible for most practical purposes.
How Much Wider is a 305/70r16 Tire Than a 285/70r17?
The 305/70r16 tire is 0.79 inches (20mm) wider than the 285/70r17. The 305/70r16 has a width of 12.01 inches (305mm), while the 285/70r17 is 11.22 inches (285mm) wide.
This 6.6% difference in width is the most significant dimensional change between these two tire sizes.
Our Observation
Switching from 305/70R17 to 285/70R17 tires offers a balanced compromise between on-road and off-road performance. The narrower width may slightly reduce dry traction but could improve fuel efficiency and snow performance.
Off-road, the difference in ground clearance is negligible, while the narrower profile might enhance maneuverability in tight spots. The minimal impact on speedometer accuracy is a plus.
Overall, this change presents more benefits than drawbacks for most users, offering a versatile tire option that performs well in various conditions without requiring vehicle modifications.
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.