Navigating the world of tires can feel like deciphering a secret code. Tire sizes, with their seemingly random numbers and letters, often leave car owners scratching their heads. One common question we hear is, “What size tire is a 315/70R17?” Understanding this seemingly cryptic code is crucial for maintaining your vehicle’s performance, handling, and safety. This comprehensive guide will demystify tire sizes, specifically focusing on the 315/70R17 designation, and equip you with the knowledge to make informed decisions about your tires.
Decoding the Tire Size Code
Tire sizes are standardized using a specific code that provides valuable information about the tire’s dimensions and construction. Let’s break down the 315/70R17 code:
Width
The first number, “315,” represents the tire’s **width** in millimeters, measured from sidewall to sidewall. In this case, a 315/70R17 tire has a width of 315 millimeters.
Aspect Ratio
The second number, “70,” is the **aspect ratio**, expressed as a percentage. It indicates the ratio of the tire’s height to its width. A 70 aspect ratio means the tire’s height is 70% of its width. So, a 315/70R17 tire would have a height of approximately 220.5 millimeters (315 x 0.70).
Construction
The letter “R” signifies the tire’s **construction**. “R” stands for radial, which is the most common type of tire construction used today. Radial tires have cords that run radially from bead to bead, providing better handling, fuel efficiency, and a smoother ride compared to bias-ply tires.
Rim Diameter
The last number, “17,” indicates the **rim diameter** in inches. This refers to the diameter of the wheel the tire is designed to fit. A 315/70R17 tire is intended for a 17-inch wheel.
Understanding the Impact of Tire Size
Choosing the right tire size is crucial for your vehicle’s performance and safety. The 315/70R17 tire size is often found on larger SUVs, trucks, and some performance vehicles. Here’s how tire size affects various aspects of your vehicle:
Handling and Performance
Wider tires, like the 315/70R17, generally provide better grip and handling, especially during cornering and accelerating. However, wider tires can also increase rolling resistance, which may slightly reduce fuel efficiency. (See Also: Does Big O Tires Take Walk Ins? What You Need To Know)
Ride Comfort
The aspect ratio (70 in this case) influences the tire’s sidewall height. A higher aspect ratio, like 70, typically provides a more comfortable ride by absorbing bumps and road imperfections better. Lower aspect ratios tend to offer sportier handling but can result in a firmer ride.
Ground Clearance
Tire size plays a role in your vehicle’s ground clearance. Larger tires with higher sidewalls can increase ground clearance, which is beneficial for off-road driving or navigating uneven terrain.
Speed Rating
Tire size is often associated with a **speed rating**, which indicates the maximum safe speed the tire can handle. The speed rating is typically a letter (e.g., H, V, W) and is found on the tire sidewall. Make sure your tires have a speed rating that meets or exceeds the maximum speed your vehicle is designed for.
Factors to Consider When Choosing a Tire Size
While the 315/70R17 size is suitable for certain vehicles, it’s essential to consider several factors before making a decision:
Vehicle Manufacturer Recommendations
Always consult your vehicle’s owner’s manual or the sticker located on the driver’s side door jamb for the recommended tire size. Using tires that deviate significantly from the recommended size can affect your vehicle’s handling, performance, and even void your warranty.
Driving Conditions
Consider your typical driving conditions. If you frequently drive on rough roads or off-road, you may benefit from larger tires with a higher aspect ratio for better ground clearance and ride comfort. If you prioritize fuel efficiency and smooth handling on paved roads, a lower aspect ratio tire might be a better choice.
Personal Preferences
Ultimately, your tire choice can also reflect your personal preferences. If you want a more aggressive look or improved off-road capability, you might opt for larger tires. If you prioritize a quieter and smoother ride, a lower profile tire might be more appealing. (See Also: How to Mount Car Tires? A Step-by-Step Guide)
Maintaining Your 315/70R17 Tires
Proper tire maintenance is crucial for ensuring optimal performance, safety, and longevity. Here are some essential tips for maintaining your 315/70R17 tires:
Tire Pressure
Check your tire pressure regularly, at least once a month, and before long trips. Use a reliable tire pressure gauge and inflate your tires to the recommended pressure specified in your vehicle’s owner’s manual or on the tire sidewall. Maintaining the correct tire pressure improves fuel efficiency, handling, and tire life.
Tire Rotation
Rotate your tires every 5,000 to 8,000 miles to ensure even wear and tear. Follow the recommended rotation pattern specified in your owner’s manual. Tire rotation helps balance the load distribution on your tires, prolonging their lifespan.
Wheel Alignment
Have your wheel alignment checked periodically, especially if you notice any pulling or uneven tire wear. Proper wheel alignment ensures your tires are tracking straight, reducing wear and tear and improving handling.
Tire Inspections
Regularly inspect your tires for any signs of damage, such as cuts, bulges, or punctures. Look for uneven tread wear, which can indicate alignment issues or other problems. Address any tire damage promptly to prevent further issues.
Recap
Understanding tire sizes is essential for maintaining your vehicle’s performance, handling, and safety. The 315/70R17 tire size, often found on larger SUVs and trucks, provides a good balance of width, height, and grip. However, choosing the right tire size depends on various factors, including your vehicle’s specifications, driving conditions, and personal preferences. Always consult your vehicle’s owner’s manual for recommended tire sizes and follow proper tire maintenance practices to ensure optimal performance and longevity.
Frequently Asked Questions
What is the difference between a 315/70R17 and a 315/65R17 tire?
The main difference lies in the aspect ratio. A 315/70R17 tire has a taller sidewall (70% of the width) compared to a 315/65R17 tire (65% of the width). This means the 315/70R17 tire will provide a smoother ride and more ground clearance but may slightly reduce fuel efficiency and handling compared to the 315/65R17. (See Also: What Are Tubeless Bike Tires? The Future of Cycling)
Can I use a 315/70R17 tire on a vehicle with a 16-inch rim?
No, using a 315/70R17 tire on a 16-inch rim is not recommended. The tire size is specifically designed for a 17-inch rim. Attempting to fit a tire that is too large for the rim can damage the tire, wheel, and suspension components.
How do I know if my 315/70R17 tires are worn out?
Check your tire tread depth using a tread depth gauge. The minimum tread depth recommended for safe driving is 2/32 of an inch. Other signs of worn tires include uneven wear patterns, cracks in the sidewalls, bulges, or vibrations while driving.
What is the best way to store my 315/70R17 tires when not in use?
Store your tires in a cool, dry place away from direct sunlight and heat sources. Keep them clean and inflate them to the recommended pressure. Consider using tire covers to protect them from dust and debris.
Can I rotate my 315/70R17 tires with tires of a different size?
It’s generally not recommended to rotate tires of different sizes. Rotating tires of the same size ensures even wear and tear and helps maintain optimal handling and performance. Consult your vehicle’s owner’s manual for specific recommendations on tire rotation.