How much bigger can I go on my tires?

Baseline guidance: you can typically run tires about 3% larger in overall diameter than stock. Some vehicles tolerate up to roughly 5% with careful planning, but larger increases can cause rubbing, miscalibrated speedometers, and drivetrain or suspension issues. This article explains how to gauge your limits and fit bigger tires safely.

The amount you can safely go bigger depends on several factors, including your vehicle’s design, wheel well clearance, suspension travel, brake clearance, and electronics such as the speedometer and ABS. Read on for practical rules, calculations, and steps to assess what your specific vehicle can handle.

Understanding Tire Sizing and Fit

Understanding how tire sizes are described helps you predict what a bigger tire will do to diameter, width, and overall fit. The following points explain what to look for when considering a larger tire.

What the numbers mean

Tire sizes like 245/45R18 break down as follows: 245 mm is the section width in millimeters, 45 is the aspect ratio (sidewall height as a percentage of width), R indicates radial construction, and 18 is the wheel diameter in inches. The overall tire diameter is roughly 2 × (section height) + wheel diameter, which determines how much bigger the tire will be than stock.

• Overall diameter increase affects speedometer accuracy and gearing (final drive ratio).


• Width and offset influence how the tire sits in the wheel well and under the fenders.


• Clearance is needed at full steering lock, suspension compression, and when the suspension is aired out or loaded.


• Brake caliper and rotor clearance must be sufficient for the larger tire.


• Load rating and tire construction must meet vehicle weight and payload requirements.


• Ventilation and heat management can change with a bigger tire, especially under heavy use.

In short, a bigger tire isn’t just about the contact patch; it’s about how the whole system—the wheel well, suspension, brakes, and electronics—handles the change. The main takeaway is that you must consider clearance, calibration, and performance trade-offs before committing to a size increase.

Practical guidelines: How much bigger is safe?

Before choosing a size, it’s helpful to have a framework for what counts as a safe and practical increase. The list below highlights the common limits and when to reconsider.

• Diameter change: aim for roughly a 1–3% increase in overall diameter as your baseline. Some vehicles tolerate up to about 5% with proper checks, but this is less common.


• Width and wheel compatibility: the tire width should match a compatible wheel width and offset to avoid rubbing on the control arms, struts, or fenders.


• Clearance: ensure there is adequate clearance at full steering lock, suspension compression, and when the suspension is loaded (e.g., with a passenger and cargo).


• Instrumentation: speedometer, odometer, and ABS may need recalibration if the diameter changes significantly.


• Brakes and gearing: larger tires can increase stopping distance and alter acceleration; gearing may feel different due to taller tires.


• Warranty and legality: many manufacturers void warranties or run afoul of local laws if modifications are excessive or not properly documented.

Bottom line: start with a modest increase, verify clearance and calibration, and be prepared for potential adjustments to suspension, braking, or electronics. If in doubt, consult a tire and wheel professional or your vehicle’s dealer.

Steps to determine how much bigger you can go

Use these steps to quantify your options before purchasing new tires. The list is designed to be a practical workflow you can follow or share with a tire shop.

• Identify your stock tire size and wheel size from the door jamb sticker, owner’s manual, or existing tires.


• Calculate the new overall diameter for candidate sizes using a tire size calculator or the math: new diameter ≈ 2 × (width × aspect_ratio) + (wheel diameter × 25.4).


• Check for potential rubbing by measuring clearances with a test-fit or by consulting a professional to gauge fender, arch, and brake clearances.


• Assess speedometer and drivetrain impact; consider a recalibration if the change exceeds a few percent.


• Evaluate suspension and wheel well space across full range of motion and with typical cargo.


• Confirm load rating and ensure the tires meet or exceed your vehicle’s weight requirements.


• Decide whether the modification is compatible with warranty terms and local laws; obtain written guidance if needed.


• Plan for an alignment after installation to optimize handling and tire wear.

Following these steps helps you avoid common pitfalls and identify any necessary supporting changes before you hit the road.

Vehicle Type Considerations

Passenger cars and sedans

Generally tighter tolerances in the wheel wells mean you’ll want to be cautious. A small diameter increase is common, but larger increases may require trimming or fender work, and could affect ride quality and calibration. Always confirm clearance at full suspension travel and lock-to-lock steering.

SUVs and pickups

Often offer more room in the wheel wells, which can accommodate larger tires with relatively fewer issues. Still, check brake clearance, sway bar clearance, and any lifted or lowered suspension geometries. Bigger tires can affect aerodynamics and fuel economy more noticeably on these vehicles.

Performance and off-road vehicles

Performance platforms may tolerate certain increases well, but stock diffs and gearing can become mismatched with much larger diameters. Off-road builds may prioritize ground clearance and traction, yet still require attention to steering geometry, alignment, and tire pressures to avoid rubbing or binding on obstacles.

Legal, Warranty, and Safety Considerations

Modifying tire size can have implications for warranty coverage, insurance, and legal compliance in some regions. Some manufacturers specify acceptable tire sizes, and aftermarket choices may affect vehicle certification and safety systems. Always verify with the vehicle manufacturer and, if needed, consult a qualified technician before making changes.

What to Do Next

If you’re considering bigger tires, start with a conservative increase, verify clearance and calibration, and then seek professional help to finalize the choice and installation.

Summary

In short, you can usually go a modest amount bigger—typically around a 1–3% increase in overall diameter, with up to about 5% in some cases. The key is to measure, model, and verify clearance, braking, and instrumentation before committing. Use a systematic approach: know your stock sizes, calculate the new diameter, check fender and brake clearances, calibrate instruments if needed, and have a professional confirm fitment and safety. With careful planning, you can achieve a bigger tire setup that preserves safety, reliability, and road manners.

Is a 285 the same as a 33?

No, a "285" is not the same as a "33" because "285" is a tire's width in millimeters, while "33" usually refers to a tire's approximate overall height in inches. However, a common tire size, like a 285/70R17, is approximately 33 inches tall and is often called a "33-inch tire" in practice. 

Feature	What it means
285	The width of the tire in millimeters (approx. 11.22 inches).
70	The aspect ratio, which is the sidewall height as a percentage of the width (70% of 285mm).
R17	The tire is designed for a 17-inch wheel rim.
33	The approximate overall height of the tire in inches, which is calculated using the width, aspect ratio, and rim diameter.

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How to calculate the approximate height:

1. Convert width to inches: 285mm÷25.4mm/inch≈11.22285 m m divided by 25.4 m m / i n c h is approximately equal to 11.22285𝑚𝑚÷25.4𝑚𝑚/𝑖𝑛𝑐ℎ≈11.22 inches. 
2. Calculate sidewall height: 11.22 inches×0.70 (the aspect ratio)≈7.8511.22 inches cross 0.70 (the aspect ratio) is approximately equal to 7.8511.22 inches×0.70 (the aspect ratio)≈7.85 inches. 
3. Calculate overall diameter: (7.85 inches×2)+17 inches (rim diameter)≈32.7open paren 7.85 inches cross 2 close paren plus 17 inches (rim diameter) is approximately equal to 32.7(7.85 inches×2)+17 inches (rim diameter)≈32.7 inches. 
4. Round to the common size: Since 32.732.732.7 inches is very close to 33 inches, a 285/70R17 tire is commonly referred to as a 33-inch tire. 

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. 

Can you go from 265 to 275 tires?

Yes, you can go from 265 to 275 tires, as the size difference is minimal and typically fits on the same wheel with no major issues. This change is about 101010 mm wider, which is a small increase that generally doesn't cause problems with speedometer accuracy or steering, and is often within the recommended 3% tolerance for tire size changes. However, you should still check your vehicle's specifications, the wheel's recommended size, and make sure the new tires are compatible with your vehicle's load capacity.
 
Key considerations

• Wheel fitment: 275mm is a common and acceptable width for many rims that originally came with 265mm tires. 
• Clearance: Ensure there is enough clearance for the slightly wider tire in the wheel well, especially when turning. The increased width is only about 101010 mm, which is a very small change. 
• Speedometer and odometer: The speedometer will be slightly affected, but the change is so small that it's often negligible. The difference in speed is typically less than a 222 mph variation. 
• Load rating: Make sure the new 275 tires have an appropriate load rating for your vehicle. 
• Rim width: Check the recommended rim width range for the 275 tire. Many common rims will accommodate both sizes. 
• Tire type: The specific type of tire (e.g., all-season, off-road) and its construction can affect the overall feel, even with similar size specifications. 

This video explains the differences between 265 and 275 tires: 59sTire BloggerYouTube · Jul 23, 2024
Before you switch

• Check your vehicle's manual and the sticker on the driver's side door jamb for the recommended tire sizes and load ratings. 
• Verify the ideal rim width for the 275/70/17 tire in the product specifications. 
• Consider the impact on your vehicle's performance, such as a slight change in fuel economy, steering feel, or handling. 
• If possible, test fit the tires before buying them to ensure there are no clearance issues. 

How much bigger can you go on tire size?

When changing tire sizes, we recommend staying within 3% of the diameter/height of the original tire. Any more than this and you face the risk of brake failure. This tire calculator is for information purposes only and we do not guarantee fitment based on this calculator alone.