Can I put 20 rims instead of 18?

In many cases, you can upgrade from 18-inch to 20-inch rims, but it isn’t automatic. Fit depends on the vehicle’s bolt pattern and center bore, the wheel offset and width, brake clearance, and finding tires that keep the overall rolling diameter close to stock. A professional fitment check is essential before buying.

What follows is a practical guide to understanding the main fitment considerations, how to preserve safe handling, and the steps you should take before committing to 20-inch rims.

Key fitment considerations

Before you shop for 20-inch rims, check these core physical factors to determine whether they will fit without rubbing or clearance issues.

• Bolt pattern and center bore: The wheel must match your vehicle’s hub profile. Even small differences can prevent proper mounting.


• Offset (ET) and backspacing: Offsets outside the OEM range can push wheels inward or outward, causing fender or suspension contact.


• Rim width and tire width compatibility: The combined width of wheel and tire should be compatible with the car’s fenders and suspension geometry.


• Brake clearance: Larger or different calipers/rotors can interfere with some 20-inch rims.


• Hub-centric vs lug-centric fit: Some aftermarket wheels rely on lug-centric mounting and may require adapters or spacers.


• Tire availability and sizing: You need tires that fit the 20-inch rims and carry appropriate load and speed ratings.


• Load rating and durability: Wheels and tires must bear the vehicle’s weight and dynamic loads safely.

Bottom line: If any of these factors don’t align with your vehicle, 20-inch rims may not fit properly without modifications.

Maintaining diameter and drivability

Keeping the overall rolling diameter close to stock helps preserve speedometer accuracy, gearing, ABS/ESC behavior, and ride quality.

• Keep rolling diameter within a small percentage of stock (commonly within about 2-3%).


• Choose tire sizes that achieve a similar overall diameter to the original setup; this often means a lower profile on 20-inch wheels.


• Be aware that larger rims with very low-profile tires can increase road harshness and affect ride comfort.


• Some vehicles may require speedometer calibration or ECU reprogramming if the diameter shifts significantly.


• Unsprung weight increases with larger rims, which can affect handling and braking feel.

Conclusion: A diameter mismatch can lead to accuracy errors in the speedometer and potential safety concerns; aim for a precise fit or plan for calibration if needed.

Practical steps to decide and implement

To minimize risk and ensure a safe, legal upgrade, follow these steps before buying 20-inch rims.

• Consult the vehicle’s owner manual or manufacturer guidelines for wheel size recommendations and limits.


• Have a tire and wheel shop measure your current fitment and verify compatibility for 20-inch rims with your specific model and trim.


• Confirm the bolt pattern, center bore, and acceptable offset range for 20-inch wheels on your vehicle.


• Choose rims that match or are very close to the OEM offset and width specs; avoid large deviations unless a qualified tuner approves them.


• Check brake clearance and tire sidewall options that provide adequate ground clearance and protection against rubbing.


• Verify load rating for both wheels and tires, ensuring they meet or exceed the vehicle’s sprung and unsprung weight demands.


• Test fit and alignment: Have a professional mount, balance, and align the wheels; inspect for rubbing at full steering lock and suspension travel.


• Assess warranty and insurance implications: Some warranties or lease agreements may restrict wheel or tire modifications.


• Plan for possible recalibration or programming adjustments if your vehicle’s electronics rely on wheel size data.

Conclusion: A careful, professional assessment reduces the risk of rubbing, miscalibration, and warranty issues, increasing the likelihood of a successful 20-inch upgrade.

Summary

Upgrading from 18-inch to 20-inch rims is possible for many vehicles, but it requires thorough checks of bolt pattern, center bore, offset, width, brake clearance, and tire options, plus ensuring the overall diameter remains close to stock. If you can’t meet these fitment and safety criteria, or if the upgrade would significantly alter ride quality or electronics, stick with the original size or consult alternatives such as different tire profiles or staggered setups. Always seek a professional assessment before purchasing and mounting new rims.

Do 20 inch rims affect gas mileage?

Yes, 20-inch rims can negatively affect gas mileage primarily due to increased weight and potential changes in aerodynamics. Heavier rims require more power to accelerate and brake, which leads to higher fuel consumption. Additionally, the larger size and different designs of 20-inch wheels can create more wind resistance, further decreasing fuel efficiency.
 
Key reasons for the impact on gas mileage

• Weight: 20-inch rims and the tires that fit them are often heavier than smaller options. This increased rotating mass requires more energy, and therefore more fuel, to get the vehicle moving and to maintain speed. 
• Aerodynamics: Larger wheels, especially off-road or more open-spoke designs, can catch more wind. This increased air resistance, or drag, means the engine has to work harder to overcome it, reducing your gas mileage. 
• Rolling Resistance: The larger surface area of wider, 20-inch tires can increase friction with the road. This higher rolling resistance contributes to a lower MPG because more energy is needed to keep the tires moving. 
• Potential for taller tires: If the 20-inch rims are paired with tires that are taller than the original equipment, it can also affect gear ratios, which can negatively impact fuel economy in stop-and-go city driving. 

Factors that can influence the impact

• Tire and wheel design: The specific design matters. Lighter-weight 20-inch rims with an aerodynamic design will have less of a negative impact than heavy, less aerodynamic ones. 
• Tire profile: The height of the tire's sidewall affects the ride and handling. Tires with lower, or "shorter," sidewalls that come with 20-inch rims can provide better performance but may result in a bumpier ride and still lead to a fuel economy decrease. 

Is it bad to change rim size?

Larger wheels and tires change the suspension angles and could even affect your transmission's gear ratio. In some cases, brakes, especially anti-lock brakes, are affected. You may need to make suspension and brake changes to compensate for these problems.

Is there a big difference between 18 and 20 inch wheels?

Smaller diameters, thicker tires, and more sidewall sizes are used in 18-inch wheels. The 20-inch wheels are quite larger in diameter, with thinner tires and sidewalls.

Is 18 or 20 wheels better for a truck?

18-inch wheels are generally better for ride comfort, off-road performance, and durability due to their taller sidewalls, while 20-inch wheels are often chosen for a sportier look and crisper on-road handling. The choice depends on your priorities: prioritize a smoother ride and off-road capability with 18-inch wheels, or a more aggressive on-road stance and handling with 20-inch wheels.
 
18-inch wheels 

• Ride comfort: Offers a smoother ride by providing more cushion from bumps and rough roads. 
• Off-road performance: Taller sidewalls provide more protection for the wheel and allow for lower tire pressure, which increases the contact patch for better traction. 
• Durability: The thicker sidewalls are less likely to be damaged by potholes or curbs. 
• Cost: Tires for 18-inch wheels are often more affordable due to larger-scale production. 

20-inch wheels 

• On-road handling: Provides a firmer, more responsive feel with less sway and better control on dry pavement. 
• Appearance: Offers a sportier, more modern look. 
• Potential downsides: The shorter sidewalls are more susceptible to damage from impacts and can result in a harsher ride over bumps. 
• Tire cost: Tires can be more expensive, as there is less demand and they are produced in smaller quantities. 

Which should you choose?

• Choose 18-inch wheels if: You prioritize a comfortable ride, plan to drive on rough terrain or do off-roading, and want better wheel protection and durability. 
• Choose 20-inch wheels if: You prioritize a sporty appearance and feel, primarily drive on highways, and are willing to sacrifice some ride comfort and durability.