245/45R20 Tire Size Guide

The 245/45R20 code breaks down into four basic parts. The 245 is the tire's section width in millimeters, 45 is the aspect ratio, the R means radial construction, and 20 is the wheel diameter in inches. Put together, it describes a relatively wide, low-profile radial designed for a 20-inch wheel.

Unlike older alphanumeric or numeric sizes, this format gives you an actual metric width and a direct sidewall proportion in the code itself. What it does not tell you by itself is whether every 245/45R20 has the same load rating, speed capability, sidewall style, or rim width range, so those details still need to be checked on the specific tire being considered.

The 245/45R20 fits a 20.0-inch wheel, which is 508.0 millimeters in diameter. That diameter must match exactly, because a 20-inch tire will not seat correctly on a wheel of any other diameter even if the width seems close.

Wheel width matters too. For the products offered in this size, the working rim width range is 7.50 to 9.00 inches. Staying within that span helps the tire keep its intended profile and contact patch. A wheel that falls outside that range can change sidewall shape, steering response, and clearance, so the wheel should be measured rather than assumed.

The 245/45R20 has a section width of 245 millimeters, which converts to 9.65 inches. Section width is the tire's widest point from sidewall to sidewall when mounted and inflated under standard measuring conditions.

Tread width is usually narrower than section width, so the sidewall-to-sidewall figure is the one that matters most for fitment. Fender edges, inner wheelhouses, struts, and suspension links all care about the tire's maximum bulge. When buyers are comparing alternatives, section width is often the first dimension to check before looking at diameter or appearance.

The 245/45R20 has an overall diameter of 28.68 inches, or about 728.47 millimeters. Overall diameter measures the tire from the ground to the top of the tread, straight through the center.

Diameter affects more than appearance. It changes wheel-opening fill, ride height, and the relationship between tire rotation and road speed. When a replacement size is shorter or taller than 28.68 inches, the vehicle can sit differently and the speedometer may read differently. Buyers comparing substitutions should use diameter as a primary reference point, not just wheel size or section width.

The 245/45R20 has a sidewall height of 4.34 inches, which is about 110.24 millimeters. That number comes from taking 45 percent of the 245-millimeter section width.

A sidewall this short helps explain why the size has a low-profile appearance and a more direct visual relationship to the wheel. In practice, sidewall height influences ride compliance, impact harshness, and how much the tire fills the opening without looking tall. Buyers moving from a higher-series tire often notice the shorter sidewall immediately, both in stance and in steering feel.

The 245/45R20 turns about 703.2 revolutions per mile. That figure reflects how many full rotations the tire makes to travel one mile under calculated dimensions for this size.

Revolutions per mile are useful when comparing substitute sizes because they tie directly to rolling distance. If another size turns meaningfully more or fewer times per mile, the speedometer and odometer can shift accordingly. Buyers replacing one size with another should compare revs per mile alongside overall diameter, especially on vehicles where gearing, electronic calibration, or appearance all matter.

No. A matching 20-inch wheel diameter is only one part of 245/45R20 tire fitment. The vehicle also needs the right wheel width, enough clearance for a 9.65-inch section width and 28.68-inch overall diameter, and a load rating that matches the way the vehicle is used.

Brake package size, suspension layout, offset, and whether the tire is being used on the front, rear, or all four corners can all affect fitment. Modern vehicles that share a wheel diameter still may not share the same tire envelope. Compare the existing tire's sidewall markings, check vehicle documentation, and confirm physical clearance before treating this size as a replacement candidate.

The 245/45R20 is used on wheels from 7.50 to 9.00 inches wide in the product range offered for this size. That span supports the intended sidewall shape and helps the tire maintain its designed footprint and profile.

Mounting the tire on a wheel narrower than 7.50 inches can pinch the casing and make the sidewall stand up more than intended. Going wider than 9.00 inches can flatten the profile and move the sidewall outward, which may affect steering response and clearance. Wheel diameter and wheel width need to be correct together, not treated as separate decisions.

It can work for a modernized build, but it is fundamentally a modern radial size with low-profile proportions. On a vehicle being judged closely for factory originality, buyers should confirm whether a short 45-series radial and 20-inch wheel fit the visual period they are trying to recreate.

On the other hand, many street-driven customs, pro-touring builds, and updated classics use modern radial sizing specifically to gain contemporary road manners and wheel options. The decision usually comes down to priorities: authentic period appearance on one side, or modern stance and drivability on the other. Clearance, load needs, and wheel width still have to be checked either way.

The 245/45R20 typically gives a firmer, more direct feel than a taller-profile tire because its 45-series sidewall is relatively short. With less sidewall height to flex, steering inputs often feel quicker and the tire tends to present a lower, more performance-oriented stance.

Ride character still depends on the vehicle, alignment, wheel width, suspension condition, and the tire's specific construction details. On rough pavement, a shorter sidewall usually transmits more road texture than a taller touring profile would. Buyers who want crisp response often like that tradeoff, while buyers prioritizing compliance may want to compare the overall diameter and sidewall height of alternate sizes carefully.

The 245/45R20 is a modern radial size used on contemporary performance and passenger vehicles, so its basic dimensions suit current road speeds and driving patterns. Radial construction generally supports more stable tracking and more predictable behavior than older construction types when the tire is in good condition and properly matched to the vehicle.

Actual highway behavior still depends on the specific tire, its load rating, speed category, inflation, alignment, and age. A low-profile size can feel precise on smooth pavement but less forgiving over broken surfaces or expansion joints. Before long interstate trips, inspect the tires for wear, cuts, bulges, and cracking, and make sure all four positions are carrying tires appropriate for the vehicle's requirements.

With an overall diameter of 28.68 inches and about 703.2 revolutions per mile, the 245/45R20 establishes a specific ride height and rolling distance. Any substitute size that changes those numbers can alter wheel-opening fill, gearing feel, and the speed shown on the speedometer.

A shorter replacement usually lowers the car visually and turns more times per mile, while a taller one can raise the stance and turn fewer times per mile. Even when the wheel diameter stays at 20 inches, a different width or aspect ratio can shift the vehicle's look and response. Compare diameter, sidewall height, and section width together before making a change.

The 245/45R20 is available from BFGoodrich, Nitto, and Pro-Trac in the current product range for this size. Those options cover a mix of modern radial performance-oriented offerings and appearance-driven variations within the same basic size.

Brand choice should be weighed alongside the tire's intended use, sidewall style, load rating, and wheel compatibility rather than by name alone. A buyer replacing one damaged tire on a regular-use vehicle may prioritize matching the existing set, while someone building a fresh set may focus on construction consistency and the look they want from all four tires.

A quality 245/45R20 tire starts with the right fundamentals: correct size, radial construction that matches the intended use, an appropriate load rating, and compatibility with the wheel width being used. In this size, the tire also needs to maintain the low-profile proportions that make 245/45R20 look and behave as expected.

Beyond that, buyers should compare uniformity across the set, current sidewall markings, and whether the tire's visual presentation suits the vehicle. On a daily-driven vehicle, consistency in all four tires usually matters more than chasing a visual detail. On a specialty build, sidewall appearance may carry more weight, but fitment discipline still comes first.

Yes. The 245/45R20 is offered with blackwall, redline, and raised white letter sidewall treatments, and that can change the look of the vehicle even when the dimensions stay exactly the same. Sidewall style is an appearance choice, but it often becomes a major part of the finished stance on cars and trucks with visible 20-inch wheels.

Blackwall usually gives the most understated modern look, while redline and raised white letter styles create a more deliberate visual statement. Buyers building a matched set should keep the same sidewall treatment at all four corners unless they are correcting an existing mixed setup. Appearance does not override fitment, so load, wheel width, and clearance still need to remain the first checks.

A 245/45R20 in regular service should be inspected routinely, not just at rotation time. Look for uneven wear, punctures, sidewall cuts, bulges, vibration changes, and signs of air loss, especially because a lower-profile tire can show the effects of curb contact or pothole impact more quickly than a taller one.

Monthly pressure checks and a visual inspection before longer trips are smart habits for this size. Pay attention to inner-edge wear if the vehicle runs a performance-oriented alignment or uses staggered wheel positions. Catching wear patterns early can help prevent replacing one tire prematurely and can also reveal wheel, suspension, or alignment issues before they become more expensive problems.

The 245/45R20 is normally a tubeless fitment. Even so, tube use is a wheel-and-tire-system question rather than a size question, so the actual tire and the actual wheel should be checked together before installation.

Modern radial passenger sizes like this are commonly mounted tubeless on compatible wheels, but damaged rims, specialty wheels, or unusual applications can change the conversation. Buyers should inspect the wheel's bead area and valve setup, and follow the guidance supplied for the specific tire being used. When there is any uncertainty, a qualified tire professional should confirm the correct assembly method.

An occasionally driven 245/45R20 can still age out before it wears out. Time, heat cycles, sunlight, ozone exposure, and long periods of sitting all affect rubber condition, even when tread depth still looks usable.

Stored vehicles should be kept clean, properly inflated, and away from direct sunlight, electric motors, and damp surfaces when possible. If the vehicle sits for long periods, move it periodically or support it in a way that helps avoid prolonged flat spotting. Before putting a low-mileage vehicle back into regular road use, inspect each tire carefully for cracking, hardening, or air loss.

The 245/45R20 should be replaced when age or condition raises concern, even if tread depth looks acceptable. Cracking, bulges, repeated air loss, impact damage, vibration that cannot be corrected, or irregular wear are all stronger warning signs than tread depth alone on an older tire.

Low annual mileage does not stop a tire from aging. Buyers should inspect current sidewall markings, check the tire's overall condition, and be realistic about how and where the vehicle is driven. A tire used for short local trips may present different risks than one expected to cover sustained interstate miles, but visible deterioration matters in either case.

Load capacity should always be confirmed against the vehicle's real requirement. In the current 245/45R20 product range, published examples include 1,929 lb at 50 psi and 1,930 lb at 50 psi per tire, so buyers need to verify that the selected tire meets the vehicle's axle demands at its specified operating condition.

Load figures should never be separated from the pressure at which they apply. A tire that looks similar in size may not carry the same load at the same pressure, and mixed sets can complicate that further. Review the current sidewall markings on the actual tire being used and compare them with the vehicle's requirements before assuming any 245/45R20 is interchangeable.

No single size code answers that by itself. The 245/45R20 tells you the tire's dimensions and construction format, but buyers still need to review the actual tire's current sidewall markings, load capability, speed category, and intended use before treating it as suitable for every driving situation or jurisdiction.

Roadworthiness depends on the whole assembly: tire condition, wheel compatibility, inflation, and how the vehicle is used. Before long trips or seasonal use changes, inspect the tires carefully and confirm that all four match the vehicle's needs. Local requirements can vary, so it is wise to review applicable regulations and consult a qualified tire professional when anything about fitment or service use is unclear.