P245/40ZR17 Tire Size

All You Need to Know About P245/40ZR17 Tires

P245/40ZR17 tires are approximately 24.7 inches tall, 9.6 inches wide, and built for 17-inch wheels. The “P” prefix identifies the tire as a P-metric passenger-car tire, while the “ZR” designation identifies a high-speed radial performance category commonly associated with ultra-high-performance and reinforced performance tire lines.

Compared with P245/40R17 tires, the P245/40ZR17 category is more heavily concentrated in performance-oriented tire families rather than comfort-focused touring applications. Drivers comparing the non-P version should also review 245/40ZR17 tires, which share the same dimensional geometry but are labeled without the explicit passenger-car prefix.

P245/40ZR17 is frequently used where a vehicle requires both substantial tread width and high-speed stability. The size is common on performance sedans, rear-wheel-drive coupes, tuned street cars, and aftermarket wheel setups where steering precision and tread stability matter more than ride softness.

P245/40ZR17 Size Quick Specs

• Wheel diameter: 17 inches
• Approved rim width range: 8.0-9.5 inches
• Measuring rim width: 8.5 inches
• Section width: 245 mm, or approximately 9.6 inches
• Sidewall height: approximately 98 mm, or 3.9 inches
• Overall diameter: approximately 24.7 inches
• Circumference: approximately 77.6 inches
• Common service descriptions: 91W, 95W XL, 95Y XL, depending on tire model

Note: Actual mounted dimensions vary slightly between manufacturers because tread profile, casing design, and measuring-wheel standards differ by tire model.

What Does P245/40ZR17 Mean?

P245/40ZR17 breaks down as follows:

• P = P-metric passenger-car tire classification
• 245 = section width in millimeters
• 40 = aspect ratio; sidewall height equals 40% of tire width
• ZR = high-speed radial tire category
• 17 = wheel diameter in inches

The service description following the size remains critical. For example, a P245/40ZR17 95Y XL tire combines:

• 95 load index
• Y speed rating
• XL reinforced construction

Load index 95 corresponds to 1,521 pounds per tire when properly inflated and used within rated conditions.

Why the P-Metric Prefix Matters in P245/40ZR17

The “P” designation identifies the P245/40ZR17  tire as a passenger-car tire under P-metric load standards. That distinction matters because P-metric and Euro-metric tires can share the same physical dimensions while following different load calculation conventions.

When a P-metric tire is installed on certain trucks or SUVs, industry load tables generally require a load-capacity reduction factor of approximately 1.10. This reduction does not apply in normal passenger-car use, but it becomes important when drivers move the tire into heavier-duty applications.

Because P245/40ZR17 is primarily used on passenger cars and performance sedans, most applications remain within normal P-metric operating conditions. However, load index verification still matters, especially on heavier vehicles or staggered rear-wheel-drive platforms.

Drivers comparing fitments without the passenger prefix should also review 245/40ZR17 to understand how manufacturers label different performance tire lines.

P245/40ZR17 and High-Speed Stability

P245/40ZR17 is commonly chosen for vehicles that place substantial lateral load on the tire during cornering and braking. The wide tread footprint improves contact-patch stability, while the short 40-series sidewall reduces excessive tread movement during fast steering transitions.

Compared with narrower performance sizes:

• 245-width tires typically provide more dry-road grip
• the wider tread creates stronger braking stability
• cornering support improves on heavier performance vehicles
• steering effort can increase slightly
• hydroplaning resistance depends heavily on tread design and inflation pressure

Because the size is performance-oriented, many P245/40ZR17 tires are built with reinforced belt packages, stiffer shoulders, and XL construction to maintain tread stability at speed.

Wheel Width and Sidewall Shape in P245/40ZR17

P245/40ZR17 is sensitive to wheel width because the tire combines a relatively wide tread with a low-profile sidewall. The approved wheel-width range is commonly 8.0-9.5 inches, while many manufacturers measure the tire on an 8.5-inch wheel.

On narrower wheels:

• the sidewall becomes more curved
• steering response may feel slower
• impact absorption can improve slightly

On wider wheels:

• the sidewall becomes straighter
• steering response usually sharpens
• the wheel lip becomes more exposed
• ride harshness can increase

For this reason, P245/40ZR17 should not be selected by diameter alone. Wheel width, offset, suspension clearance, and intended vehicle use all influence how the tire behaves after installation. For deeper wheel-width guidance, read: Rim Width Range and Fitment Limits.

Common P245/40ZR17 Tire Categories

P245/40ZR17 is heavily concentrated in performance-oriented categories rather than standard touring lines. Common categories include:

• ultra-high-performance summer tires
• performance all-season tires
• track-capable street tires
• reinforced XL fitments

Summer performance models typically prioritize:

• dry grip
• steering precision
• heat resistance
• cornering stability

Performance all-season models usually balance:

• year-round drivability
• wet traction
• cool-weather usability
• daily comfort

Choosing Wheels for P245/40ZR17 Tires

When replacing wheels alongside P245/40ZR17 tires, verify:

• wheel diameter
• wheel width
• bolt pattern
• offset
• center bore
• brake clearance
• suspension clearance
• wheel load rating
• fender clearance

Browse compatible wheel and rim options here: NeoTires Wheels & Rims.

For complete wheel-fitment guidance, read: Aftermarket Wheel Fitment: 7 Specs You Can't Get Wrong.