Replacing 275 60R20 with 275 55R20 Tires.

In the world of automotive care, tire replacement can be a complex task. One of the most common questions we hear is, “Can I replace 275 60R20 with 275 55R20 tires?”

This article aims to provide a comprehensive answer to that question, alongside a detailed exploration of tire sizing, the implications of changing tire sizes, and a closer look at these specific tire measurements.

Understanding Tire Size Notations

The notation 275 60R20 or 275 55R20 is not random jargon; it represents the key dimensions and characteristics of a tire.

Tire Width

The first number (275 in this case) signifies the tire width in millimeters. Therefore, both 275 60R20 and 275 55R20 tires have the same width, which is 275 millimeters.

Aspect Ratio

The second number (60 or 55) is the aspect ratio, which denotes the height of the tire sidewall as a percentage of the tire’s width.

A 275 60R20 tire has an aspect ratio of 60%, while a 275 55R20 tire has an aspect ratio of 55%. The lower the aspect ratio, the shorter the tire’s sidewall.

Radial Construction and Rim Diameter

The ‘R’ in the notation indicates that the tire has radial construction. Finally, the last number (20) represents the rim diameter in inches. Both 275 60R20 and 275 55R20 tires are designed for 20-inch rims.

What Happens When You Replace 275 60R20 with 275 55R20 Tires?

Replacing a 275 60R20 tire with a 275 55R20 tire resulted in a change in the tire’s sidewall height due to the different aspect ratios. Here’s a closer look at the implications of this change:

Sidewall Height

The sidewall height of a 275 60R20 tire is 165mm (60% of 275mm), while the sidewall height of a 275 55R20 tire is approximately 151.25mm (55% of 275mm). This change in sidewall height can impact various aspects of vehicle performance.

Speedometer Accuracy

Since the diameter of the 275 55R20 tire is less than that of the 275 60R20 tire, it may result in a slight increase in the speedometer reading.

Your speedometer might show you’re traveling faster than you actually are because the smaller tire completes more revolutions per mile.

Fuel Efficiency and Ride Comfort

A tire with a lower aspect ratio, like the 275 55R20, might improve fuel efficiency due to its lower rolling resistance. However, a tire with a shorter sidewall usually provides a firmer ride, potentially reducing ride comfort.

Vehicle Handling

Tires with lower aspect ratios are often associated with improved handling and cornering performance. This means that replacing your 275 60R20 tires with 275 55R20 ones could enhance your vehicle’s responsiveness and stability during high-speed maneuvers.

Potential Risks of Replacing 275 60R20 with 275 55R20 Tires

While there might be benefits to making the switch, it’s also important to be aware of the potential risks involved in changing tire sizes. Some of these risks include:

Load Carrying Capacity

Tires with a shorter sidewall like the 275 55R20 generally have a lower load index than their counterparts with a higher aspect ratio.

This means that the maximum weight the tires can safely support may be reduced. Always check the load index when considering a tire size change to ensure that the replacement tires can adequately support your vehicle’s weight.

Clearance Issues

A change in tire size could potentially lead to clearance issues, especially in vehicles with minimal clearance between the tire and the vehicle body or suspension components.

While the overall diameter of the 275 55R20 tire is less than the 275 60R20 tire, it is crucial to verify that the reduced height will not cause any clearance problems.

Tire Pressure Monitoring System (TPMS)

The TPMS might not accurately read the tire pressure if you change from 275 60R20 to 275 55R20 tires. This could lead to incorrect tire pressure readings and potentially compromise the safety of your vehicle.

Considerations Before Making the Change

Before deciding to replace your 275 60R20 tires with 275 55R20 tires, it’s important to consider several factors:

Vehicle Manufacturer Recommendations

Your vehicle manufacturer provides specific tire size recommendations for your vehicle model. These recommendations are designed to ensure optimal vehicle performance and safety.

It is always advisable to stick to the manufacturer’s recommendations unless you have a compelling reason to make a change.

Tire Size and Vehicle Warranty

Altering your vehicle’s tire size may affect your vehicle’s warranty. It is essential to review your warranty terms and conditions to understand if and how a tire size change might impact your coverage.

Professional Advice

Consult with a tire or automotive professional before making a decision. They can provide specific advice based on your vehicle type, driving habits, and local driving conditions.

Professional Installation vs. DIY

Deciding between professional installation and DIY for your new tires can be tricky – let’s explore the pros and cons together so you can make the best decision for you.

If you’re a car enthusiast, doing the installation yourself could be a fun project to take on. You’ll get to know your car even better, and you’ll save money on labor costs.

However, if you’re not an experienced mechanic, you could end up making an expensive mistake. Professional installation is more expensive, but you’ll have the peace of mind of knowing the job was done correctly.

If it’s not done right, you’ll have to pay for another installation, and you could be putting your safety at risk.

So, it’s important to weigh the pros and cons of each option carefully when deciding between professional installation and DIY.


While it is technically possible to replace 275 60R20 tires with 275 55R20 tires, it is essential to understand the implications of this change.

Factors such as speedometer accuracy, fuel efficiency, ride comfort, and vehicle handling may be affected.

Potential risks include changes to the load-carrying capacity, potential clearance issues, and inaccurate TPMS readings.

Before making the decision, consider your vehicle manufacturer’s recommendations, your vehicle warranty, and seek professional advice.

Tire size changes should not be made lightly, and it is critical to prioritize safety and vehicle performance over any potential benefits of a different tire size.

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