The 325/65R18 tire comes with an overall diameter of 34.6 inches (879 mm), a tread width of 12.8 inches (325 mm), and is built for 18-inch (457 mm) wheels. It has a sidewall height of 8.3 inches (211 mm) and a circumference of 108.8 inches (2764 mm), resulting in about 582 revolutions per mile (362 per kilometer).
Offering a wide footprint and strong grip, this tire size provides reliable traction, stability, and ground clearance, making it well-suited for heavy-duty trucks and SUVs on highways or off-road terrain.
You can read more about Tire Sizes on our site.
Tire Dimensions: 325/65R18 in Inches and Metric
When choosing tires, knowing the exact dimensions is crucial. Whether you’re upgrading your truck for off-road adventures or need a reliable tire for daily driving, understanding the measurements in both metric and inches helps ensure the right fit for your vehicle.
| Specification | Inches | Metric (mm) |
| Revolutions Per Mile | 583 | 362 per km |
| Tire Width | 12.8 in | 325 mm |
| Wheel Diameter | 18 in | 457 mm |
| Overall Diameter | 34.6 in | 879 mm |
| Sidewall Height | 8.3 in | 211 mm |
| Circumference | 108.6 in | 2760 mm |
These measurements give you a clear picture of how big these tires are compared to other options. The large diameter and wide tread provide excellent stability, making them ideal for off-road enthusiasts, heavy-duty vehicles, and lifted trucks.
Understanding the Meaning of 325/65R18
At first glance, 325/65R18 might look like a random string of numbers and letters, but it actually tells you important details about the tire’s size and construction. Let’s break it down:
- 325: This is the tire’s width in millimeters. In simple terms, it means the tire is 325 mm (12.8 inches) wide from side to side.
- 65: This is the aspect ratio, meaning the sidewall height is 65% of the tire’s width. The taller the sidewall, the better it absorbs shocks and handles uneven roads.
- R: The “R” stands for Radial construction, which is the most common tire design today. Radial tires provide better stability, traction, and longevity.
- 18: This refers to the rim diameter, meaning the tire is designed to fit on an 18-inch wheel.
In short, 325/65R18 tires are wide, tall, and built for durability, making them perfect for trucks, SUVs, and off-road vehicles that demand strong performance.
325/65R18 Size Conversion to Inches
If you’re more comfortable with inches instead of millimeters, here’s how 325/65R18 converts to inches:
- Tire Width: 12.8 inches
- Sidewall Height: 8.3 inches (65% of 12.8 inches)
- Overall Tire Diameter (Height): 34.6 inches (including both sidewalls and rim diameter)
- Circumference: 108.6 inches
- Revolutions Per Mile: 583 (This means the tire completes 583 full rotations in a mile)
Knowing these numbers is important because it helps you compare tires, determine fitment, and understand how these tires will affect your vehicle’s handling and ride quality.
Is a 325/65R18 All-Terrain Tire the Right Choice?
If you love off-road driving, muddy trails, or rocky terrains, you might be wondering if an all-terrain tire is a better option for your vehicle.
How Do All-Terrain Tires Compare to Highway Tires?
- All-Terrain Tires: Designed for on-road and off-road use, featuring deeper treads and reinforced sidewalls for better durability.
- Highway Tires: Offer better fuel efficiency and a quieter ride, but lack the grip needed for off-road adventures.
Tread Design & Performance
- Deep, aggressive treads: Improve grip on mud, dirt, and sand.
- Stronger sidewalls: Resist punctures when driving over rough terrain.
- Siping technology: Enhances traction on wet roads and icy conditions.
If you frequently switch between city roads and off-road trails, all-terrain tires provide the best of both worlds. However, if you mainly drive on highways, you might prefer a set of highway-focused tires for better fuel economy.
Top Brands Offering 325/65R18 Tires
Choosing the right 325/65R18 tires isn’t just about size—it’s also about quality and performance. While multiple brands manufacture this tire size, it’s important to look at factors like tread design, durability, and user reviews before making a decision.
What to Consider When Choosing a Brand?
Not all tires are created equal. Here’s what to look for when picking the best 325/65R18 tires:
- Tread Pattern: Determines performance on different surfaces (highway vs. off-road).
- Rubber Composition: Affects durability and wear resistance.
- Sidewall Strength: Important for preventing punctures and improving handling.
- Warranty & Longevity: Some brands offer better mileage warranties than others.
Brand Comparison Without Promotions
While we won’t promote specific brands, here’s what you should know about different types of 325/65R18 tires:
- Premium brands tend to offer longer-lasting tread, better grip, and improved ride comfort but come at a higher price.
- Mid-range options provide a balance between affordability and performance, making them ideal for everyday drivers.
- Budget-friendly choices may work for those who drive less frequently or don’t need extreme off-road durability.
Before purchasing, check customer reviews and manufacturer specifications to see which brand fits your driving needs.
Understanding Load Index and Speed Rating
When selecting 325/65R18 tires, you’ll notice they come with a load index and speed rating. These two factors determine how much weight your tires can support and how fast they can safely travel.
What is the Load Index?
The load index refers to the maximum weight a tire can carry when properly inflated. It’s represented by a number on the tire’s sidewall, which corresponds to a specific weight in pounds.
For example:
- A load index of 120 means the tire can carry about 3,086 lbs per tire.
- Multiply this by four, and your vehicle can safely support over 12,000 lbs on all four tires.
Why is the Speed Rating Important?
The speed rating tells you the maximum speed a tire can handle while maintaining stability and performance. It’s marked by a letter, such as “S,” “T,” or “H”:
- S-rated tires: Safe up to 112 mph.
- T-rated tires: Safe up to 118 mph.
- H-rated tires: Safe up to 130 mph.
Most off-road and all-terrain tires have lower speed ratings since they’re designed for durability rather than high-speed driving.
How Load Index and Speed Rating Affect Performance?
- Higher load index tires are best for towing and heavy cargo.
- Lower speed-rated tires are better for off-road adventures and durability.
- If you drive primarily on highways, look for a tire with a higher speed rating for a smoother ride.
Understanding these ratings ensures you choose the right tire for your driving needs, whether it’s heavy hauling, off-roading, or high-speed travel.
Which Vehicles Can Use 325/65R18 Tires?
If you’re considering upgrading to 325/65R18 tires, the first step is ensuring they will fit your truck or SUV. These tires are wider and taller than standard options, making them an excellent choice for off-road adventures and heavy-duty driving. However, not every vehicle can accommodate them without modifications.
Common Vehicles That Fit 325/65R18 Tires
These tires are typically used on larger trucks and SUVs that require higher ground clearance and better traction. Some common models that can fit 325/65R18 tires include:
- Ford F-250 & F-350 Super Duty
- Chevrolet Silverado 2500 & 3500
- Dodge Ram 2500 & 3500
- Toyota Tundra (Modified Versions)
- GMC Sierra 2500 & 3500
If your vehicle isn’t on this list, don’t worry! You can still check compatibility by looking at your owner’s manual or consulting a professional.
Will These Tires Fit Your Truck or SUV?
To see if 325/65R18 tires will fit your vehicle, consider these factors:
- Check Your Wheel Well Clearance – These tires are larger than standard stock tires, so you need enough room for proper movement.
- Look at Your Suspension System – Some trucks may require a leveling kit or lift to prevent rubbing.
- Verify Your Gear Ratio – Larger tires can affect acceleration and fuel economy, so adjusting your gear ratio may be necessary.
Do You Need a Lift Kit for 325/65R18 Tires?
Since these tires have a 34.6-inch diameter, some vehicles may need a suspension or body lift for proper clearance.
- A 2–3 inch lift may be required for trucks with tight wheel wells.
- A leveling kit can help prevent rubbing against fenders or suspension components.
- Some vehicles may handle them without modifications, but always test fit before installation.
If you’re unsure whether you need a lift, it’s best to consult with a tire expert or an off-road specialist to avoid potential issues.
325/65R18 Tires vs. Other Similar Sizes: How Do They Compare?
When choosing the right tire size, it’s helpful to compare 325/65R18 tires to other popular options like 315/70R18 and 285/75R18. Each size has its own advantages, so understanding the differences in width, height, and performance can help you make the best decision for your vehicle.
How Do These Tire Sizes Measure Up?
| Tire Size | Width (inches) | Overall Diameter (inches) | Sidewall Height (inches) | Revolutions per Mile |
| 325/65R18 | 12.8 in | 34.6 in | 8.3 in | 583 |
| 315/70R18 | 12.4 in | 34.4 in | 8.6 in | 586 |
| 285/75R18 | 11.2 in | 34.8 in | 8.4 in | 580 |
Key Differences in Size and Performance
- Width Comparison
- 325/65R18 tires are the widest, offering better traction and grip, especially in off-road conditions.
- 315/70R18 tires are slightly narrower, which may improve fuel efficiency and reduce rolling resistance.
- 285/75R18 tires are the narrowest, making them a better fit for vehicles with smaller wheel wells.
- Height and Sidewall Differences
- 325/65R18 tires have a moderate sidewall height, offering a balance of durability and comfort.
- 315/70R18 tires have a slightly taller sidewall, which can absorb bumps better but may lead to a softer ride.
- 285/75R18 tires have the tallest sidewall, making them ideal for off-road shock absorption but potentially less stable at high speeds.
- Best Uses for Each Tire Size
- 325/65R18: Best for off-road traction, towing, and heavy-duty trucks needing maximum stability.
- 315/70R18: A great middle-ground option, offering solid off-road performance without as much bulk.
- 285/75R18: Ideal for fuel efficiency, on-road performance, and vehicles with limited wheel space.
Overall, 325/65R18 tires are the best choice for drivers who prioritize traction, stability, and durability—especially for off-road and all-terrain driving. If you want a more balanced or fuel-efficient option, one of the other sizes might be a better fit.
Final Verdict: Are 325/65R18 Tires Worth It?
Most drivers agree that 325/65R18 tires are an excellent investment for off-roaders, truck owners, and anyone needing a strong, durable tire. While they aren’t the best choice for fuel efficiency or smaller trucks, they offer incredible traction, stability, and longevity making them a top choice for serious drivers.
If you’re looking for professional tire repair services, don’t hesitate to contact us for expert assistance.
FAQs
Q. What size is 325/65R18?
A 325/65R18 tire is 12.8 inches wide, 34.6 inches tall, and fits an 18-inch wheel, making it a great option for trucks and SUVs.
Q. How tall is a 325/65R18 tire?
The overall diameter of a 325/65R18 tire is 34.6 inches, providing excellent ground clearance and stability for off-road and heavy-duty driving.
Q. What vehicles can use 325/65R18 tires?
These tires are commonly used on Ford F-250, Chevrolet Silverado 2500, Dodge Ram 2500, and other large trucks and SUVs.
Q. Do 325/65R18 tires improve off-road performance?
Yes, with their wide tread and strong sidewalls, these tires offer superior traction on mud, sand, and rocky trails, making them ideal for off-roading.
