What the biggest size of tires will fit my truck?

The largest tire size you can safely fit on your truck without major modification is typically around 33 inches in overall diameter on stock suspension, with 33-34 inch options possible on some models using a leveling kit or modest lift. Larger sizes (35 inches and up) are generally achievable only with suspension upgrades, wheel choices, and careful clearance checks. The exact limit depends on your truck’s make, model, year, trim, and how you intend to use the vehicle.

This guide explains how to calculate the true maximum for your specific truck, what factors limit fit, and how to approach upgrades safely. We’ll walk you through stock specifications, clearance constraints, and a step-by-step process to determine the biggest tire your truck can accommodate.

Know your baseline: stock specifications

Understanding your factory measurements is the essential first step. Start with the numbers that define your starting point before considering any tire or suspension changes.

• Factory tire size and wheel diameter (for example, 265/70R17 or 275/65R18).


• Wheel width and offset/backspacing of the rims you’re using or plan to use.


• Current suspension setup (stock, leveling kit, or a lift kit and its inches of height).


• Any existing fender liners, mud flaps, or bumper configurations that affect clearance.

With these details in hand, you can gauge how much extra diameter and width you can add before rubbing or interference becomes a problem.

Key constraints that limit tire size

Many factors determine whether a larger tire will fit. It’s not just about diameter; width, offset, and how the tire interacts with the vehicle’s body and drivetrain all matter—and some issues only appear when you turn or bounce over rough terrain.

• Front and rear clearance: sufficient space for tire movement during suspension compression and articulation, especially at full steering lock.


• Fender and bumper clearance: potential rubbing with factory or aftermarket body components, sometimes requiring trimming or fender flares.


• Wheel offset and backspacing: affects how far outward the tire sits; improper offset can cause rubbing on control arms, springs, or body panels.


• Suspension modifications: leveling kits, lifts, and their impact on geometry and clearance.


• Drivetrain and steering components: CV joints, tie rods, and steering knuckles must have room to travel without binding.


• Brake components and calipers: wider tires may require larger wheel diameters or clearance checks around calipers and rotors.


• Wraparound consequences: speedometer calibration, ABS sensors, and overall vehicle electronics may need adjustment after tire changes.

Understanding these constraints helps you plan modifications or confirm that a certain tire size will work without compromising safety or performance.

How to determine the maximum fit for your truck

Use a structured approach to calculate and verify the largest tire size for your vehicle, combining data gathering with practical testing and professional guidance if needed.

1. Gather baseline data: confirm your stock tire size, wheel size, offset, and whether the truck has any factory or aftermarket suspension modifications.


2. Consult fitment guides: use manufacturer fit guides (or reputable retailers’ fitment databases) to identify the largest tires listed as compatible with your exact year/model and wheel width.


3. Estimate clearance: locate the front fender lip and check for rub margins at full lock and full bump. If the tire looks likely to rub, plan for a small lift, trimming, or fender adjustments.


4. Consider wheel choice: ensure the chosen tires match a wheel with compatible width and offset; incorrect offset can push tires into the suspension or fenders.


5. Test-fit and measure: if possible, perform a real-world test fit by turning the wheels to full lock and measuring any contact points with a tape measure or cardboard cutouts, and check clearance at full suspension compression.


6. Factor only-safe upgrades: decide whether a leveling kit, a modest lift, or fender modifications are appropriate for your use case and local regulations.


7. Account for speedometer and gearing: larger tires will alter speedometer accuracy and may affect gearing and fuel economy; plan for recalibration if needed.


8. Plan for safety and warranty: consult your vehicle’s warranty terms and local regulations, and consider professional installation and alignment services.

By following these steps, you can determine a practical maximum tire size for daily driving, off-road use, and long-term reliability tailored to your truck.

Practical examples by truck type

Without committing to a single model, several common scenarios illustrate typical outcomes. On many full-size pickups, stock suspensions commonly accommodate up to about 33 inches in overall diameter. A leveling kit or modest lift can allow 33-34 inches, while more extensive lifts with proper wheels and trimming can push into 35 inches or more. Always verify with model-specific fit guides and, when in doubt, consult a tire or off-road shop to confirm clearances for your exact build.

Summary

Finding the biggest tire size for your truck is a balance between stock specifications, physical clearance, and practical goals. Start with your factory tire and wheel data, check fitment guides for your exact year and trim, and verify clearance through careful measurements and testing. If you plan to exceed stock dimensions, anticipate suspension adjustments, wheel choice considerations, potential trimming, and the need for speedometer recalibration and professional alignment. With a systematic approach, you can identify the largest tire size that fits your truck safely and reliably.

Are 33 tires the same as 285?

No, "33" is the overall tire diameter in inches, while "285" is the tire's width in millimeters. A "285" tire is not always a "33," as the overall height depends on the tire's aspect ratio and rim diameter. For example, a common tire size of 285/70R17 is approximately 32.7 inches tall, while a 285/75R16 is closer to 32.8 inches tall. 
Tire size components

• 285: The width of the tire's tread in millimeters. 
• 70: or 75 (Aspect Ratio): The height of the tire's sidewall as a percentage of the width. For a 285/70R17, the sidewall height is 70% of 285mm. 
• R: Indicates the tire is "Radial" construction. 
• 17: or 16 (Rim Diameter): The diameter of the wheel in inches. 

Calculating the overall diameter
To determine the overall height, you can use this formula: 

• (Width x Aspect Ratio / 25.4) x 2 + Rim Diameter = Overall Diameter 
• For example, a 285/70R17 is: (285×0.70/25.4)×2+17≈32.7 inchesopen paren 285 cross 0.70 / 25.4 close paren cross 2 plus 17 is approximately equal to 32.7 inches(285×0.70/25.4)×2+17≈32.7 inches. 

Key takeaways

• "33" is a marketing term for the overall height, while "285" is a metric measurement of the tread width. 
• A 285 tire is not necessarily a 33-inch tire; it depends on the other numbers in the size designation. 
• Many tires marketed as "33s" are metric sizes like 285/70R17 or 285/75R16 because their calculated diameter is very close to 33 inches. 

Are 285 tires bigger than 275?

A 285 tire is generally taller than a 275 tire, but the exact height difference depends on the tire's aspect ratio. However, a 285 tire is always wider than a 275 tire. 
How tire size works

• The first number in a tire size (e.g., 275 or 285) indicates the tire's width in millimeters. 
• The second number is the aspect ratio, which is the height of the tire's sidewall as a percentage of its width. 
• The "R" stands for radial construction. 
• The final number indicates the diameter of the wheel in inches that the tire fits. 

Height comparison

• A 285 tire is wider, and for a given aspect ratio, it will have a taller sidewall, making it taller overall. 
• For example, a 285/60R20 tire is taller than a 275/60R20 tire. 
• To find the exact height difference, you can use a tire size calculator or compare the overall diameter of two specific tire sizes, as the height is calculated based on both the width and aspect ratio. 

What's the biggest size tire I can put on my truck?

The largest tire you can put on your truck depends on whether you have a stock or modified suspension, as well as the specific make and model of your truck. A good rule of thumb is that you can fit a tire up to about 33 inches in diameter on a stock suspension, while a lifted truck can accommodate 37 inches or larger, though for anything significantly bigger, you will need to perform more modifications. For a definitive answer, it's best to take some measurements or consult a professional.
 
On a stock suspension

• General guideline: On average, you can fit tires up to about 33 inches without modifications. 
• Examples:
  • A Ford F-150 can typically fit a 33-inch tire. 
  • A Toyota Tacoma can fit a 31.5-inch tire. 
  • A stock 2021 Ram 1500 can fit 275/65/20s (almost an inch taller) without issue, but larger tires will likely rub. 
• Considerations: A slightly wider tire may fit, but a significantly wider one could cause rubbing issues, especially when turning, according to this Reddit post. 

On a lifted or leveled truck

• General guideline: A leveling or lift kit will allow you to fit much larger tires. A common rule is that for every inch of lift, you can fit an extra inch of tire height. 
• Examples:
  • A 37-inch tire is often achievable with a lift. 
  • Modern trucks with a leveling kit can commonly fit 37 or even 38-inch tires. 
• Considerations: The lift manufacturer will usually specify the maximum compatible tire sizes for their product, so check the product's guidelines. 

How to get the most accurate answer

• Measure: Get out a tape measure and check the clearance around your current tires. Measure from the tire's edge to suspension components and body panels. 
• Check your offset: The offset of your wheels will impact how much room you have. Wheels with a more negative offset will push the tires out further, potentially requiring a larger lift to fit a bigger tire. 
• Consult a professional: Contact a tire and wheel specialist who can advise you on the best tire size for your specific make and model, along with any necessary modifications like fender trimming or a lift kit. 

How much bigger is 70 vs 65 tires?

A tire with a 70 aspect ratio is bigger (taller) than a tire with a 65 aspect ratio, assuming the other numbers in the size are the same. The 70 is 5% taller in the sidewall, which means the overall tire is about 1 inch taller. The 70-aspect ratio tire has a sidewall that is 70% of its width, while the 65-aspect ratio tire has a sidewall that is 65% of its width.
 

• Example: A 265/70R17 tire is taller than a 265/65R17 tire. 
• Side-by-side: The 265/70R17 is about 1 inch taller overall than the 265/65R17 tire. 
• Impact: This height difference results in a slightly more capable off-road tire with a taller sidewall, but it can affect your speedometer accuracy and potentially cause clearance issues.