When you see a tire marked 315/70R17, it might look confusing—but it’s actually a precise code that tells you the tire’s key dimensions.
These tires are common on trucks and SUVs due to their rugged size. Knowing what each number means and how it converts into real-world measurements in inches can help https://www.tanzohubs.com/hygropack-complete-guide-to-humidity-control-solutions/ you choose the right tires, understand fitment, and calculate speedometer accuracy.
This article breaks everything down about these key codes,measurements etc which is easy to understand with FAQs.
Understanding the Tire Code
A tire labeled 315/70R17 includes three components:
- 315: The tire’s width in millimeters (sidewall to sidewall).
- 70: The aspect ratio—this is 70% of the width, meaning sidewall height.
- R17: Indicates radial construction and that the tire fits a 17‑inch rim.
Once you translate these numbers into inches, you can confidently compare tire sizes and ensure fitment.
315/70R17 in Inches
Width in Inches
- 315 mm ÷ 25.4 = 12.4 inches wide. This is the tire’s maximum breadth.
Sidewall Height
- 12.4 in × 0.70 = 8.7 inches for the sidewall (rim to tread).
Overall Diameter
- (2 × 8.7 in) + 17 in = 34.4 inches total height when inflated and unloaded.
Total Circumference
- Diameter × π ≈ 34.4 × 3.14 = 108 inches (roughly).
Revolutions per Mile
- Around 587 revolutions per mile, meaning how many times the tire turns in one mile of travel.
Why These Measurements Matter?
Vehicle Fit and Performance
Choosing the right width and diameter ensures your tire fits wheels and has adequate clearance in the wheel well. This affects handling, braking, and safety.
Speedometer Accuracy
If the tire is larger or smaller than stock size, your speedometer may read incorrectly. For 315/70R17, changes are small but noticeable compared to stock sizes.
Ride Quality
A taller sidewall (like 8.7 inches) helps cushion bumps and rugged terrain, common in off-road use.
Fuel Economy & Torque
Heavier and larger tires may reduce fuel mileage and change vehicle gear behavior—know what you’re fitting.
Popular Alternatives & Comparisons
- A similar size in high flotation notation is 35×12.4R17—slightly larger, about 1.74% taller and 0.8% wider than 315/70R17.
- If compared to 315/75R17 tires, the 70-series is about 1.24 inches smaller in diameter, which affects speedometer readings by around 3.5%.
Fitment & Compatibility
- Rim Size: Works with 17-inch rims—widths from 8.0 to 10.5 inches are recommended (wide vehicles often require 10–11 inches).
- Vehicle Types: Common on light-truck, SUV, and off-road vehicles.
- Lift and Clearance: May require suspension or body clearance tweaks depending on vehicle setup.
Real‑World Example
Suppose a truck originally comes with 285/70R17 tires as its stock size. If the owner decides to switch to 315/70R17 tires, the overall diameter https://fr.wikipedia.org/wiki/Diameter increases by approximately 0.6% to 1.7%, depending on brand and tread depth. This size change may cause a slight difference in handling characteristics, such as a firmer ride or marginally altered steering response. However, the benefits include wider tread coverage and a taller sidewall, which together provide improved off-road traction, better grip on uneven surfaces, and enhanced stability on rough terrains. It’s a popular upgrade for those looking to boost their truck’s performance and rugged appeal.
FAQs
1. What does “315/70R17” mean?
It denotes a tire that is 315 mm (12.4 inches) wide, 70% aspect ratio (sidewall height), radial build, and fits a 17-inch rim.
2. How tall is this tire?
Its total diameter is approximately 34.4 inches (874 mm).
3. What width is 315/70R17 tire?
It has a section width of about 12.4 inches (315 mm) .
4. What is the sidewall height?
About 8.7 inches (220.5 mm), which is 70% of its width.
5. How many times does this tire turn per mile?
Approximately 586–587 revolutions per mile.
6. Can it fit standard 17-inch rims?
Yes—recommended rim widths range between 8.0 and 10.5 inches .
7. Is 315/70R17 bigger than stock tires?
It depends on your stock size. It’s taller than typical midsize truck tires and common in off-road upgrades.
8. Will this size change speedometer readings?
Yes—switching from smaller sizes may result in a 3–5% speedometer error.
9. Is it good for off-road use?
Yes—wide tread and tall sidewalls offer better traction and cushioning on rugged terrain.
10. Which size is similar?
35×12.4R17 is very close—just about 1.7% taller—another popular choice for lifted trucks.
Conclusion
The 315/70R17 tire is a strong and reliable choice, especially popular for trucks and SUVs. When translated into inches, it measures approximately 12.4 inches in width, with a sidewall height of about 8.7 inches, and a total diameter of around 34.4 inches.
The tire’s circumference is close to 108 inches, and it completes about 586 to 587 revolutions per mile. This size is well-suited for off-road use, offering improved traction, durability, and towing https://www.tanzohubs.com/money6x-com-building-assets-explain/capability. It fits 17-inch rims with the right width and gives the vehicle a taller stance.
Understanding these measurements in inches helps ensure the right fit, keeps the speedometer reading correctly, and prevents clearance issues.
