245/40R17 Tire Size Guide

The 245/40R17 size code breaks down into four parts: 245 is the section width in millimeters, 40 is the aspect ratio, R means radial construction, and 17 is the wheel diameter in inches. In practical terms, this size is about 9.65 inches wide, uses a 17-inch wheel, and has a calculated sidewall height of 3.86 inches.

Compared with older alphanumeric or numeric sizes, this format tells you much more directly about width and profile. It still does not tell you everything, though, because load capacity, speed rating, sidewall style, and intended performance category can vary from one 245/40R17 tire to another. Buyers should read the full sidewall markings and compare the exact tire against the vehicle's required specifications.

The 245/40R17 fits a 17.0-inch wheel, which is 431.8 millimeters in diameter. The 17-inch dimension is fixed and must match exactly, because a tire built for a 17-inch bead seat will not mount correctly on a wheel of any other diameter.

Wheel width matters along with wheel diameter. In this size, the available tires fit rims from 7.00 to 9.50 inches wide, although individual tires within the size may favor narrower or wider portions of that range. A broader wheel can sharpen the profile, while a narrower one can round the sidewall more. Buyers should confirm both the wheel width and the exact tire's fitment guidance before installation.

The 245/40R17 has a section width of 245 millimeters, which converts to 9.65 inches. Section width is measured at the widest point of the inflated sidewalls, so it represents the tire's maximum body width rather than the tread width that actually contacts the road.

Clearance decisions should be based on section width first, because that is the part of the tire most likely to approach fender lips, strut housings, inner liners, or suspension hardware. Tread width is usually narrower than section width, so relying on tread measurements alone can lead to surprises. When replacing another size, compare both width and wheel offset to understand how the tire will actually sit in the opening.

The 245/40R17 has a calculated overall diameter of 24.72 inches, or about 627.9 millimeters. That figure measures the tire from the ground to the top of the tread through the center when mounted and inflated, and it is one of the most important comparison points when evaluating a substitute size.

Overall diameter affects more than appearance. A larger diameter can raise ride height and reduce wheel-well clearance, while a smaller one can lower the car slightly and change the way the speedometer and odometer read. On cars with tight front fender clearance or carefully tuned suspension geometry, even modest diameter changes can alter stance and turning clearance enough to matter.

The 245/40R17 has a calculated sidewall height of 3.86 inches, or 98.0 millimeters, on each side of the wheel. Because the aspect ratio is 40, the sidewall height is 40 percent of the tire's 245-millimeter section width, which gives this size its low-profile character.

A sidewall this short usually delivers a firmer, more immediate feel than a taller touring size, but it also leaves less cushion between the wheel and the road. Drivers often notice that potholes, expansion joints, and rough pavement become more important with a 40-series tire. Wheel protection, ride comfort, and impact sensitivity should all be considered along with handling response when choosing this profile.

The 245/40R17 turns about 815.9 revolutions per mile. That number comes from the tire's 77.66-inch circumference and helps show how often the tire rotates over a given distance, which is useful when comparing substitute sizes for speedometer and gearing effects.

A tire with more revolutions per mile is effectively smaller in rolling diameter, while one with fewer revolutions per mile is larger. Even when two sizes look close on paper, the difference in revolutions per mile can still affect indicated road speed, odometer accuracy, and the way the vehicle feels at cruising speed. Compare this figure any time you are considering an alternate fitment.

No. The 245/40R17 shares width and wheel diameter with some other 245-section 17-inch sizes, but the 40-series profile is a major part of the fitment. A 245/45R17 or 245/35R17 may fit the same wheel diameter, yet change overall height, clearance, and speedometer behavior enough to create problems on a vehicle designed around 245/40R17.

Vehicle compatibility depends on the complete size, not just the first and last numbers. Buyers should compare overall diameter, section width, wheel width, offset, and the front or rear position being replaced. On performance cars especially, a small change in profile can alter fender clearance, steering sweep, and stance. Original door-jamb placards, owner's manuals, and current wheel specifications remain the best starting points.

The 245/40R17 fits wheels from 7.00 to 9.50 inches wide in the tires offered here. That is the practical fitment window for this size, but individual tire models can sit differently within that range because casing shape and intended use vary even when the nominal size is the same.

A 7.00-inch wheel will pull the sidewalls in more, while a 9.50-inch wheel will spread the tire wider and flatter. Either condition can influence steering feel, sidewall support, and visual stance. Buyers replacing an original fitment should confirm the actual wheel width on the car rather than assuming all 17-inch wheels are equivalent, especially if the vehicle has aftermarket wheels or staggered fitment.

The 245/40R17 is fundamentally a modern low-profile radial size, so it suits later performance-oriented builds more naturally than earlier factory-style restorations. Its proportions, short sidewall, and 17-inch fitment reflect modern handling priorities rather than the taller sidewall look associated with most earlier original-equipment applications.

For a driver-focused build, radial construction can improve road manners and steering response. If the goal is a judged restoration, however, buyers should compare the vehicle's original tire specification, wheel diameter, and overall visual stance before choosing this size. A car can drive well on a modern radial and still look noticeably different from its original delivery appearance, especially around wheel-opening fill and sidewall profile.

The 245/40R17 usually delivers a quicker, more immediate feel than a taller-profile tire because its sidewall is only 3.86 inches tall. Less sidewall height generally means less deflection in corners, sharper turn-in, and a more connected steering response, which is why this size is common on performance-oriented passenger cars.

Ride quality often becomes firmer as the profile gets shorter. Road joints, broken pavement, and pothole impacts are transmitted more directly, and wheel protection is reduced compared with a higher-series tire. Suspension condition, alignment, inflation, and wheel width all influence the final result, so two vehicles on the same 245/40R17 size can still feel quite different in everyday use.

The 245/40R17 is a radial size intended for modern road use, and its low-profile dimensions usually favor responsive lane changes and stable steering feel when the vehicle and suspension are in good order. With an overall diameter of 24.72 inches, it stays relatively compact, which can help preserve the gearing and visual proportions expected from vehicles designed around this type of fitment.

Highway behavior still depends on more than size alone. Tire age, tread design, alignment, shock condition, wheel balance, and the vehicle's original suspension tuning all affect tracking and comfort. Before a long interstate run, inspect for uneven wear, sidewall damage, and air loss, and confirm that the exact tire's load and speed markings align with the way the vehicle will actually be used.

Yes. Any change away from the 245/40R17 can affect both stance and indicated speed because this size has a calculated diameter of 24.72 inches and turns about 815.9 revolutions per mile. A taller substitute will usually fill the wheel opening more and read slightly slower on the speedometer, while a shorter one can do the opposite.

Even small diameter changes can be noticeable on cars with tight fender gaps or carefully matched front and rear tire sizes. Section width also matters, since a tire that is nominally close in height may still sit differently at the sidewall. When comparing alternatives, measure wheel width and offset along with tire dimensions so the final fit preserves both clearance and the intended visual balance.

BFGoodrich is available in the 245/40R17 size here. Even within one brand, this size can appear in more than one tire line, which means buyers should look beyond the nominal size and compare the exact sidewall markings, load specification, and intended performance category before deciding which version best suits the vehicle.

Brand selection at this size is only part of the quality conversation. Construction consistency, sizing accuracy, wheel-width compatibility, and how well the tire matches the car's suspension and intended use often matter more than the name alone. For a matched set, it is also wise to keep the same tire family across the axle, and often across all four corners, unless the vehicle was engineered for a mixed setup.

A quality 245/40R17 should match the vehicle's required load capacity, fit the wheel correctly, and maintain consistent dimensions from tire to tire. In a low-profile performance size like this, uniform construction and accurate sizing matter because small differences in section width or sidewall shape are more likely to affect steering feel and fender clearance than they would on a taller, more forgiving tire.

Blackwall appearance is typical in the 245/40R17 offerings here, so the choice is driven more by fitment and use case than by sidewall styling. Buyers should compare the exact load marking, wheel-width range, and speed marking along with how the vehicle is driven. A tire chosen for regular road miles may prioritize a different balance than one selected mainly for sporty weekend use.

In most cases, yes. Keeping all four 245/40R17 tires consistent in brand family, construction, and load specification helps preserve predictable handling and even wear, especially on performance-oriented passenger cars. Mixing tires of the same nominal size but different carcass behavior or speed category can change steering response and balance more than many buyers expect.

If the vehicle uses a staggered setup from the factory, matching should still be maintained within each axle and ideally across the full set where the design allows. Buyers replacing only one or two tires should compare the remaining tires for age, wear pattern, and exact sidewall markings. Consistency matters more in a short-sidewall size because the tire contributes so directly to how the car feels on the road.

The 245/40R17 should be inspected regularly, especially if the vehicle sees daily or frequent road use. Check for uneven wear, cuts, bulges, cracking, punctures, and ongoing air loss, and pay close attention to the inner shoulder if the car uses aggressive alignment settings or performance suspension geometry.

Low-profile tires tend to show the effects of alignment and road impacts quickly because there is less sidewall to absorb irregularities. A brief visual check every few weeks and a closer inspection before longer trips can catch problems before they become expensive wheel or suspension issues. Rotation timing should follow the vehicle and tire maker's guidance, taking into account whether the fitment is square or staggered.

Tread depth alone is not enough to judge the service life of the 245/40R17. A tire can still show usable tread and yet be aging internally or externally from time, heat cycles, sunlight, ozone exposure, and repeated impact loading. That is especially important with a short-sidewall performance size, where structural condition matters as much as visible tread remaining.

Drivers should read the current sidewall date code and inspect the full tire carefully, including both shoulders and the bead area. If there are signs of cracking, vibration, repeated air loss, or impact damage, replacement may be the wiser choice even before the tread appears worn out. Age, storage history, and actual driving conditions all influence how long a tire remains suitable for continued road use.

The 245/40R17 is normally a tubeless fitment. Even so, tube use is ultimately a wheel-and-tire-system question rather than a size question, so the final answer should be confirmed against the actual tire and the exact wheel being used.

Modern one-piece tubeless wheels are the usual match for this size, but special-purpose wheels, damaged rims, or unusual applications can change the answer. Buyers should inspect the wheel's bead area and valve arrangement and follow the tire and wheel manufacturer's guidance. If there is any uncertainty about sealing condition or wheel design, a qualified tire professional should make the call before mounting.

Age matters even when tread remains. A 245/40R17 that still looks deep enough can still be a poor candidate for continued use if the rubber has hardened, the sidewalls are cracking, or the tire has been exposed to years of heat, sunlight, or ozone. Performance-oriented low-profile tires should be judged on condition and age as well as visible wear.

Before relying on an older set, inspect the tread blocks, shoulders, sidewalls, and bead areas for cracking, bulges, repairs, or impact damage. Long periods of storage or infrequent use can be just as hard on a tire as steady mileage. If the vehicle is expected to travel at interstate speeds or cover long distances, cautious buyers should weigh age and condition heavily when deciding whether replacement is due.

In the 245/40R17 tires offered here, load capacity ranges from 1,356 pounds at 51 psi to 1,521 pounds at 50 psi depending on the specific tire. Those figures are not interchangeable, so buyers should match the exact load marking of the tire they choose to the vehicle's requirements rather than assuming every tire in this size carries the same rating.

Load needs should be checked per tire and in the context of the vehicle's intended use, passenger count, and any extra cargo. A performance car may not look heavy, yet axle loads and speed expectations can still demand careful matching. Review the vehicle placard and the tire's full sidewall markings together, and avoid treating size alone as proof that the load requirement has been satisfied.

Buyers should verify wheel diameter, wheel width, tire age, current condition, and the exact load and speed markings before putting a 245/40R17 into road service. This size fits a 17-inch wheel and works across a 7.00 to 9.50-inch wheel-width range in the tires shown here, but proper road use still depends on the complete wheel-and-tire package being correct.

Roadworthiness also depends on inflation maintenance, alignment, suspension condition, and damage-free wheels. A tire in the right size can still perform poorly if the rim is bent, the bead seat is corroded, or the alignment is out. Before longer trips, inspect for cuts, bulges, uneven wear, and air loss, and confirm that the chosen tire's markings align with the vehicle's actual operating demands and local requirements.