What size tires can I go up to?

For most passenger vehicles, you can safely upsize by about one to two tire sizes in overall diameter, with some potential for modest width increases. The exact limit depends on your car’s wheel wells, suspension, braking components, and how closely you want to match speedometer readings.

This article explains how to determine the maximum tire size for your vehicle, what constraints to check, and the practical steps to confirm fitment and safety before making a change.

Key factors that limit the biggest tire you can fit

To understand what limits your upgrade, consider the main clearance and compatibility factors that can cause rubbing or safety concerns.

• Wheel well clearance: The space between the tire and the inner fender, control arms, and suspension components; insufficient clearance can cause rubbing under load or steering lock.


• Fender lip and overall exterior clearance: Rubbing against the fender lip or wheels protruding beyond the fender line can be cosmetic, legal, or functional issues.


• Suspension geometry and ride height: Lowered or lifted setups change available space and can increase rubbing risk with larger tires.


• Brake components: Larger tires may interfere with calipers, rotors, or knuckles, especially on high-performance brakes or small-diameter wheels.


• Wheel width and offset: Wider wheels or incorrect offset can push the tire outward, reducing space and increasing rubbing risk.


• Rolling circumference and gearing: A bigger diameter changes the tire’s rolling circumference, affecting acceleration, braking, and speedometer accuracy.


• Manufacturer limits and local regulations: Some vehicles have tight tolerances, and local laws may restrict tires that extend beyond the fenders.

With these factors in mind, the practical maximum is not universal; it must be evaluated for each vehicle, wheel choice, and intended use.

How to calculate and confirm your safe maximum tire size

Follow a disciplined process to determine a feasible upsize and ensure it won’t introduce safety or reliability problems.

1. Review the stock specifications: Check the owner's manual or the door jamb sticker for the factory tire size, wheel width, and offset.


2. Assess physical clearance: Measure available space in the wheel wells at straight ahead and through full steering travel to identify rubbing risk.


3. Compare rolling circumference: Choose candidate tires and compute their overall diameter; aim for no more than about a 3% difference from stock to keep speedometer/odometer accuracy reasonable.


4. Check wheel compatibility: If you’re staying with the same wheels, verify that wider tires won’t rub on calipers, control arms, or the fenders. If you’re changing wheels, verify width, offset, load rating, and hub bore compatibility.


5. Evaluate braking and suspension clearance: Ensure new tires maintain adequate space from brakes, shocks/struts, and suspension components under full articulation and turning.


6. Consider performance trade-offs: Larger tires can affect ride quality, acceleration, fuel economy, and braking distance; heavier tires increase unsprung mass.


7. Consult professionals: When in doubt, visit a tire shop or your dealership for precise fitment guidance and, if needed, a professional alignment check.

Careful measurement and professional advice help prevent clearance problems and preserve vehicle safety and performance.

Considerations for your specific vehicle type

Vehicle design and purpose influence how aggressively you can upsize. The following are general expectations, not guarantees; verify with your dealership or a tire specialist before purchasing.

• Sedans and hatchbacks: Many can safely upsize by about one diameter size with compatible offsets; two sizes may be possible on some models, but rub risks rise.


• SUVs and crossovers: Typically more tolerant of larger tires, and upsize to two sizes is common on many models with proper clearance and wheel choices; three sizes can be possible in some cases but is less common.


• Trucks and heavier-duty setups: Often capable of larger upsizes, especially with lifted or modified suspensions; ensure load ratings and fender clearance remain adequate.

Note: Modifying tire size can affect warranty status and insurance coverage in some cases. Check with the manufacturer and your insurer before proceeding.

Common ranges by vehicle class (general guidance)

These ranges reflect typical real-world outcomes rather than guarantees. Your exact maximum will depend on your specific vehicle, wheel choice, and any modifications.

• Compact cars: usually upsize by about one diameter size, with occasional two-size upsizes on models with generous wheel-well space.


• Midsize sedans: often possible to upsize by one to two diameter sizes, depending on clearance and wheel offset.


• SUVs and crossovers: commonly can upscale by one to two sizes; some models allow closer to three with careful selection.


• Pickup trucks: frequently able to upsize by one to two sizes, particularly with appropriate wheel and tire packages and any necessary trimming or lift considerations.

Always verify fitment with measurements and a professional opinion before purchasing tires.

Summary

Upsizing tire size offers a noticeable mix of benefits and risks. The maximum you can go up to is determined by wheel well clearance, suspension and brake compatibility, wheel offset, and how much speedometer and gearing accuracy you’re willing to trade off. Start conservatively with a modest increase, confirm fit with precise measurements and expert guidance, and avoid sizes that rub or interfere with safety systems. If you share your vehicle’s make, model, year, current tire size, and intended goals (appearance, off-road, or performance), I can help estimate a precise maximum upsize for your setup.

Can I get bigger tires without changing rims?

Yes, you can get bigger tires without changing rims, but it depends on the rim's width and the tire's dimensions. The new tire must be compatible with your existing rim's width, and while you can increase the overall diameter, you need to be careful about potential issues like rubbing and speedometer inaccuracy.
 
Key considerations

• Rim width: The most critical factor is your rim's width, as it dictates the range of tire widths it can safely accommodate. You can't just put any larger tire on. 
• Tire dimensions: To maintain a similar overall diameter, you may need to adjust the aspect ratio (sidewall height) and width of the tire. A common practice is to "plus-size" the tire, meaning a wider tire with a lower profile that maintains a similar overall diameter. 
• Potential problems: Going too large can lead to rubbing on the wheel well, which can damage the tire and fender. It can also affect your speedometer accuracy and fuel economy, and potentially put extra stress on your vehicle's powertrain. 
• Professional advice: It is crucial to consult with a tire professional to determine the maximum size that can safely be mounted on your specific rims. 

What to do

1. Check your rim's width: Find out the exact width of your current rims. 
2. Consult sizing charts: Look up the compatible tire sizes for your specific rim width. 
3. Calculate the change: Use an online calculator to see how much a different tire size will affect your vehicle's speedometer and odometer. 
4. Get professional advice: Take your vehicle to a tire shop and ask for their recommendation on the biggest tires that can be safely mounted on your current rims. 

What is the 3 percent rule for tire size?

The tire size "3 percent rule" is a guideline that recommends replacement tires should not have a diameter that differs by more than 3% from the original equipment (OE) tires. Sticking to this rule helps ensure the speedometer is accurate, safety systems like ABS and traction control function correctly, and there are no fitment issues with wheel wells or the vehicle's drivetrain. While the rule applies to most passenger vehicles, trucks and SUVs may be able to accommodate a larger tire diameter change of up to 15% due to their more robust design. 
Why the 3% rule is important

• Speedometer and odometer accuracy: A change in tire diameter affects how many times the tire rotates to cover a certain distance, which can make your speedometer and odometer inaccurate. 
• ABS and traction control: These systems rely on sensors that are calibrated to the OE tire size. An incorrect size can cause these systems to malfunction or engage improperly. 
• Drivetrain stress: Larger or smaller tires can change the gear ratio, putting extra stress on your transmission, differential, and other drivetrain components. 
• Fitment and clearance: Going too large can cause the tire to rub against the fender or suspension components, especially when turning. 

How to check compatibility

• Use a tire size calculator: Online tools can help you compare your OE tire size with a potential new size and calculate the percentage difference in diameter. 
• Consult your owner's manual: This is the best source for official information on the correct tire sizes for your vehicle. 
• Seek professional advice: If you are considering a significant change, it's best to consult a tire professional to ensure the new tires will be safe and compatible with your vehicle. 

What is the maximum tire size increase?

The ideal maximum calculated upsize that can be done without upsetting the car's dynamics is around three percent of the original total tyre diameter. Any increase above this will result in a noticeable drop in fuel efficiency and compromise ride and handling.

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.