245/35R18 Tire Size Guide

The 245/35R18 size code gives you the key dimensions directly. In this case, 245 is the section width in millimeters, 35 is the aspect ratio, R means radial construction, and 18 is the wheel diameter in inches. Put together, it describes a low-profile radial tire built for an 18-inch rim.

Modern metric sizing like 245/35R18 is more descriptive than older numeric or alphanumeric systems because it spells out width and sidewall proportion in the code itself. What it does not tell you by itself is the exact tread width, approved wheel width range, load rating, or the precise speed symbol on every version, so those details still need to be checked on the actual tire and wheel combination.

The 245/35R18 fits an 18-inch wheel, which equals 457.2 millimeters at the bead seat. That diameter must match exactly, because a tire built for an 18-inch rim cannot be mounted correctly on a wheel of any other diameter.

Wheel width matters alongside wheel diameter. In this size, the available fitment shown here spans 8.00 to 9.50 inches wide, which is the range where the tire seats and profiles correctly. If the wheel falls outside that width range, the sidewall shape and contact patch can change enough to affect clearance, wear pattern, and steering behavior.

The 245/35R18 has a section width of 245 millimeters, which converts to 9.65 inches. Section width is the tire's widest inflated point from sidewall to sidewall, not the width of the tread that actually touches the road.

Clearance checks should be based on section width first, because that is the dimension most likely to interfere with fender lips, strut bodies, inner liners, or brake hardware. Tread width is usually narrower and can mislead buyers into thinking a tire will fit more easily than it really will once mounted on the wheel.

The 245/35R18 has an overall diameter of 24.75 inches, or about 628.65 millimeters. That figure represents the full outside height of the mounted and inflated tire measured through the center from top to bottom.

Overall diameter affects more than appearance. A change in tire height can alter ride height, wheel-opening fill, gearing feel, and speedometer behavior, so it is one of the first numbers to compare when a buyer is considering a substitute size. On a low-profile fitment like this one, even modest diameter changes can become noticeable in clearance and stance.

The 245/35R18 has a sidewall height of 3.38 inches, which is 85.75 millimeters. That number comes from the 35 aspect ratio, meaning the sidewall height is 35 percent of the tire's 245-millimeter section width.

A short sidewall is one reason this size is associated with performance-oriented applications. With less sidewall height available to flex, the tire tends to preserve a sharper visual profile and a quicker response feel than a taller tire of similar width. The tradeoff is that wheel protection, ride compliance, and tolerance for potholes depend more heavily on wheel width, suspension condition, and inflation maintenance.

The 245/35R18 turns about 814.9 revolutions per mile. That means the tire completes a little over eight hundred full rotations to cover one mile of travel under its stated dimensions.

Revolutions per mile are useful when comparing substitute sizes because they help show how speedometer and odometer readings may shift. A tire with a lower revs-per-mile figure is generally taller, while a higher figure is generally shorter. Buyers comparing replacements should look at this number together with overall diameter rather than treating section width alone as the deciding factor.

The 245/35R18 is a strong starting point when a vehicle was originally specified with that exact size, but exact fitment still depends on more than the sidewall code. Wheel width, wheel offset, axle position, suspension design, and brake clearance all influence whether the tire will fit and behave as intended.

Even among vehicles that use the same size, manufacturers can tune the package around different wheels and clearances. A buyer should confirm the original placard or owner's documentation, then compare the actual wheel setup to the tire's 8.00 to 9.50 inch wheel-width range. This matters especially on low-profile applications where small packaging differences show up quickly.

The 245/35R18 shown here fits wheels from 8.00 to 9.50 inches wide. Staying within that span helps the tire maintain its intended sidewall shape, contact patch, and shoulder profile once mounted and inflated.

A wheel near the narrow end of that range can make the sidewalls stand more upright, while a wheel near the wide end can spread the tread and change the visual stance. Neither approach should be guessed at on a short-sidewall size. Buyers should check the wheel width stamped on the rim and compare it directly before mounting.

The 245/35R18 is fundamentally a modern low-profile radial size, so it is usually chosen for contemporary fitment and drivability rather than for an older factory-authentic look. On a judged vehicle, the right answer depends on whether the car originally used a modern metric radial size and whether appearance standards matter as much as road manners.

Radial construction can improve everyday drivability, but authenticity questions are separate from performance questions. If the project is restoration-focused, compare the original tire specification, wheel dimensions, and intended stance before substituting this size. A modern 35-series profile can change the visual character of a vehicle even when the wheel diameter itself appears appropriate.

The 245/35R18 combines a 245-millimeter width with a short 3.38-inch sidewall, so it is generally associated with a more immediate steering response and a firmer ride than a taller tire. The radial construction also supports the kind of controlled tread behavior modern performance cars are designed around.

Ride and steering impressions still depend on the whole setup, not the size alone. Wheel width, suspension tuning, alignment, inflation condition, and tire age all shape how this size feels on the road. On rough pavement, the low profile usually leaves less cushion between the wheel and the road surface than a higher-series replacement would.

The 245/35R18 is a modern radial size used on performance-oriented passenger cars, so it is commonly part of contemporary road-going tire packages. Its low profile and 24.75-inch overall diameter are aimed more at handling precision and packaging than at the tall, compliant feel of older high-profile sizes.

Highway behavior still depends on the actual tire chosen, the vehicle's condition, and whether the tire's load and speed markings match the application. Buyers planning regular interstate use should inspect alignment, confirm wheel condition, and review the exact sidewall markings on the mounted tire rather than assuming every tire in the size behaves the same way.

Changing from the 245/35R18 to a taller, shorter, narrower, or wider substitute can alter speedometer readings, wheel-opening fill, gearing feel, and clearance. Because this size already uses a low 35-series sidewall, small dimensional changes can have a more noticeable effect than they would on a taller-profile tire.

Overall diameter and revolutions per mile are the first numbers to compare, followed by section width and approved wheel width. A substitute that looks close on paper can still change fender clearance or visual stance once mounted. Buyers should compare the full tire-and-wheel package, especially on cars with tight suspension or brake packaging.

BFGoodrich is available in the 245/35R18 size. Even with a single brand represented, buyers should still compare the exact construction details, load rating, and speed markings on the specific tire they are considering rather than relying on size alone.

Brand choice matters most when it aligns with the vehicle's purpose. On a modern low-profile size like this, priorities usually include dimensional consistency, proper wheel-width compatibility, predictable road manners, and a load rating that matches the car's needs. If you are replacing only two tires, consistency across the axle is especially important.

A quality 245/35R18 tire should first match the correct size, wheel diameter, and wheel-width range for the vehicle. After that, buyers should focus on radial construction details, accurate load capability, the actual speed symbol on the sidewall, and whether the tire's intended use matches how the car is driven.

Low-profile performance sizes leave less room for dimensional mismatch than taller vintage sizes do. Check that the tire fits the 8.00 to 9.50 inch wheel-width range, confirm the sidewall markings, and make sure the tire's proportions maintain the clearance and stance the vehicle was designed around. Those checks usually matter more than brand reputation by itself.

Yes, sidewall style can matter, especially when the wheel design leaves a lot of the tire visible. The example in this size uses a blackwall sidewall, which suits the understated look most buyers expect from a modern performance fitment.

Appearance should still come after the basic fitment checks. On the 245/35R18, wheel width, load rating, and the exact overall dimensions have a larger effect on how the car drives and clears than sidewall cosmetics do. Once the technical match is right, sidewall style becomes part of matching the vehicle's visual character.

The 245/35R18 should be inspected regularly for uneven wear, cuts, sidewall damage, bulges, and slow air loss, especially because a short sidewall can show the effects of potholes and curb contact more quickly. Frequent visual checks are a smart habit on any low-profile performance fitment.

Regular service use calls for more than watching tread depth. Check inflation often, inspect the inside and outside shoulders for alignment-related wear, and look over the wheel itself for bends or impact damage. On a size commonly used with performance-oriented suspensions, small handling changes can be an early sign that a tire or wheel needs attention.

A 245/35R18 can age out before the tread is fully worn, particularly if it sees heat cycling, hard road use, or long periods of underuse. Tread depth alone is not enough to judge condition, because rubber also deteriorates from time, sunlight, ozone exposure, and general aging.

Inspect the sidewalls and tread blocks for cracking, hardening, separations, or irregular wear, and review the tire's date code when evaluating older tires. A performance-oriented radial may still look usable at a glance while no longer offering the behavior the vehicle was designed around. When age or condition is in question, a qualified tire professional should inspect the tire.

The 245/35R18 is normally a tubeless fitment. Even so, tube use is a wheel-and-tire-system question rather than a size question, so the final answer should always be confirmed against the actual wheel and tire being used.

Modern 18-inch radial applications like this are typically built around tubeless wheels, but damaged rims, specialty wheels, or unusual custom setups can change the decision. Buyers should inspect the wheel's bead seat and valve area, then follow the tire and wheel guidance for the exact components being assembled rather than assuming the size code settles it by itself.

The 245/35R18 should be replaced when it shows structural damage, recurring air loss, severe uneven wear, exposed cords, bulges, or age-related cracking, even if some tread remains. On a low-profile size, sidewall and impact damage deserve especially close attention because there is less rubber height available to absorb road shocks.

Replacement timing is about condition as much as mileage. Buyers should inspect tires before long trips, after pothole strikes, and any time the vehicle develops vibration or pull. If the tire's age, internal condition, or prior damage history is uncertain, an in-person evaluation is smarter than relying on appearance alone.

In the example shown here, the 245/35R18 is rated to carry 1,389 pounds at 50 psi per tire. That figure should be matched against the vehicle's actual axle loads and the tire placard requirements, not treated as a general number that automatically suits every car using the size.

Load verification matters most when the vehicle carries passengers, luggage, or performance equipment that changes real operating weight. Buyers should compare all four tires as a set and make sure the chosen tire's sidewall markings meet the vehicle's needs. Mixing tires with different capabilities can complicate handling and replacement planning.

No, buyers should not assume every 245/35R18 is identical in its markings or intended use simply because the size matches. Road use expectations depend on the exact tire selected, its sidewall markings, its condition, and whether it meets the requirements that apply where the vehicle is registered and driven.

Check the current sidewall information on the tire itself and review local inspection or registration requirements if legality is a concern. The practical safety side is just as important: confirm wheel compatibility, inspect for damage, and make sure the tire's load and speed markings are appropriate for the vehicle before putting it into regular road service.