Tire Size 285/75r17 vs 315/70r17
The primary difference between the 285/75R17 and 315/70R17 tires is the width of the tire. The 285/75R17 tire has a width of 285 millimeters, while the 315/70R17 tire has a width of 315 millimeters. This means that the 315/70R17 tire is wider than the 285/75R17 tire.
| / | R |
| / | R |
| Parameter | 235/35 R18 | 205/40 R18 | Differ. |
|---|---|---|---|
| Tire Height | |||
| Section Width | |||
| Circumference | |||
| Sidewall Height | |||
| Revolutions | |||
| Rim Size |
Fitment Guide
When replacing tires, it is generally recommended to stay within 3% of the overall diameter of the original tires.
Going beyond this threshold often requires modifications like a leveling kit or lift kit to prevent rubbing and clearance issues.
In this comparison, the overall diameters are very close at just a 1.6% difference. This means both 285/75R17 and 315/70R17 tires should fit most vehicles without needing modifications.
Ground Clearance
The slightly larger 315/70R17 tires provide 0.27 inches more ground clearance thanks to a taller sidewall height.
This added clearance is beneficial for off-roading and driving over obstacles where scraping or bottoming out is a concern. However, the downside is that larger tires can reduce speedometer accuracy.
Gas Mileage
With a narrower tread and smaller contact patch, the 285/75R17 tires have an advantage regarding fuel efficiency.
The 10.5% increase in width of the 315/70R17 tires results in more rolling resistance, reducing gas mileage. Their extra weight also increases rotational mass, further detracting from efficiency.
Ride Comfort
The taller sidewalls and greater air volume of the 315/70R17 tires provide more cushioning from impacts like potholes and bumps.
This typically means a smoother, more comfortable ride, especially on uneven terrain. The slightly shorter sidewalls of the 285/75R17 mean impacts are less dampened.
Aesthetics
Visually, the difference between these two tire sizes is subtle. The 315/70R17 will appear a bit more “stretched” due to the extra sidewall height.
Some drivers prefer this look on trucks and SUVs over a lower-profile appearance. However, aesthetics ultimately come down to personal taste.
Handling & Stability
The 285/75R17 tire’s shorter sidewalls deliver sharper handling and quicker steering response, an advantage on paved roads.
In contrast, the extra sidewall flex of the 315/70R17 promotes stability but reduces handling precision slightly. Both offer solid overall performance.
Noise & Vibration
With its stiff sidewalls, the 285/75R17 transmits more road noise and vibration into the cabin. The 315/70R17’s flexible sidewalls absorb noise and vibration better, providing a quieter, smoother ride. However, the differences are relatively minor between these sizes.
Durability & Wear
The narrower 285/75R17 tire exhibits more even wear across its tread surface, potentially extending tread life slightly.
The wider 315/70R17 has more stress concentrated on its outer tread shoulders, increasing wear in these areas. Overall durability is comparable.
Adverse Conditions
Both tires perform well in rain, light snow, and off-road conditions. The extra ground clearance of the 315/70R17 provides a slight advantage, as does the wider tread for additional traction.
But the 285/75R17’s responsiveness also proves beneficial on loose surfaces.
Speedometer Difference
The 315/70R17 diameter results in a speedometer reading approximately 1.5% higher than the 285/75R17 at any given true speed.
For example, at an actual 20 mph, the speedometer would read about 20.31 mph with the 315/70R17 tire versus 20 mph with the 285/75R17.
What Does 315 70r17 Tire Mean?
The 315 70r17 tire size is a metric tire. The first number, 315, refers to the tire’s width in millimeters. The second number, 70, is the aspect ratio.
This is the height of the sidewall compared to the width of the tire. In this case, it’s 70%. The last number, 17, is the diameter of the wheel in inches and the letter R stands for radial construction.
285/75r17 vs 315/70r17
Here is a table that compares the differences for easy understanding at a glance.
Our Observation
The 285/75R17 and 315/70R17 tire sizes have modest differences. The wider 315 tire provides slightly more ground clearance, cushioning, and traction than the 285.
However, the narrower 285 tire delivers marginally better fuel efficiency and handling response. The choice between them depends on priorities – the 315 suits off-road needs, while the 285 optimizes on-road performance.
Visually, they are similar. Overall, the sizes are quite comparable, performing well for most trucks and SUVs. Consider intended use and individual needs when choosing between these capable options.
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.
