P245/45R17 Tire Size

All You Need to Know About P245/45R17 Tires

P245/45R17 tires use the passenger load standard, which means load capacity is calculated for passenger vehicle use rather than light-truck or commercial duty. Although P245/45R17 shares the same external dimensions as 245/45R17, the P-prefix identifies how the tire is rated for passenger-vehicle service.

With a width of 245 mm, a 45% aspect ratio, and a 17-inch wheel diameter, P245/45R17 produces an overall diameter of 25.7 inches and a sidewall height of 4.3 inches. These measurements define its physical size, while inflation pressure and load index determine how the tire performs under passenger-vehicle load conditions.

Compared with the standard 245/45R17 designation, P245/45R17 places the focus on passenger-rated load behavior for this size. That distinction matters when matching the tire to vehicle requirements, because the dimensions remain the same while the rating language becomes more specific.

P245/45R17 Size Quick Specs

• Approved rim width range: 7.5–9.0"
• The measured rim width (optimal): 8.0 inches 
• Width: 245 mm
• Sidewall height: 110.25 mm
• Overall diameter: ≈25.7"
• Wheel diameter: 17 in

Note: P245/45R17 has the same calculated dimensions as 245/45R17. Small mounted-diameter variation may still occur across manufacturers because tread depth and casing design are not identical from one tire to another.

What P Means in P245/45R17

The “P” in P245/45R17 indicates that this 245/45R17 size is identified under a passenger load standard. In practical terms, load capacity depends on inflation pressure for this size, even though the tire keeps the same 25.7-inch diameter and 4.3-inch sidewall height as 245/45R17.

That makes P245/45R17 most relevant on passenger cars and performance-oriented sedans, where ride balance, handling consistency, and correct load index matter more than any change in dimensions.

P245/45R17 Load Capacity and Pressure Behavior

In P245/45R17, load capacity increases with inflation pressure within the tire’s rated limits. If pressure drops below specification, the tire cannot maintain its intended shape as effectively, which increases sidewall flex, heat buildup, and irregular wear risk.

Because P245/45R17 uses a 45-series sidewall, pressure changes influence both ride comfort and handling balance. The sidewall is tall enough to absorb road irregularities better than a 40-series tire, but it still remains short enough that incorrect inflation can noticeably affect steering response and tread stability.

P245/45R17 Common Vehicle Applications

P245/45R17 is used on passenger sedans and performance-oriented vehicles where a balance between ride comfort, stability, and steering control is required. Typical applications include:

• Chevrolet: Camaro (1993-2002), Corvette (1997-2004), Malibu (select trims)
• Subaru: Outback (higher trims), Legacy
• Infiniti Q50
• Lexus IS
• Mitsubishi 3000GT
• Mercedes-Benz E-Class
• Chrysler 300
• Ford Mustang

In these applications, P245/45R17 reflects a passenger load standard for this size, where fitment still depends on wheel width, offset, and clearance, but load behavior is managed through the tire’s pressure and rating specifications rather than through any dimensional difference from 245/45R17.

P245/45R17 Dimensions in Inches

P245/45R17 measures approximately 9.7 inches in width, 25.7 inches in overall diameter, and has a sidewall height of 4.3 inches.

That 4.3-inch sidewall gives P245/45R17 a balanced profile. It provides more vertical compliance than a lower-profile 40-series size, while still keeping enough lateral support for stable handling in typical passenger-car driving conditions.

P245/45R17 in Inches: All Measurements

• Total diameter: ≈25.7"
• Width: ≈9.7"
• Sidewall height: ≈4.3"
• Wheel diameter: 17"
• Circumference: ≈80.7"

P245/45R17 vs 245/45R17 Tires

P245/45R17 and 245/45R17 share the same external dimensions, but the P-prefix identifies the passenger load standard for this size.

• Dimensions: identical at ≈25.7" overall diameter
• Width: identical at 245 mm
• Difference: the P-prefix specifies passenger-rated load behavior for this size

That means the correct substitution check is not about size difference, because there is none. The relevant checks are load index, inflation pressure, approved rim width, and whether the tire’s rating matches the vehicle’s requirements.

Comparison of P245/45R17 With Similar P-Metric Sizes

Within passenger performance sizing, P245/45R17 aligns with wide-section configurations that balance handling stability and ride compliance. The closest comparisons include P245/40R17 as the lower-profile alternative and P255/45R17 as a wider size that stays close in overall diameter.

Difference Between P245/45R17 and P245/40R17

The P245/40R17 is shorter while maintaining the same width:

• Width: identical at 245 mm
• Overall diameter: P245/40R17 is ≈0.96 inches (≈3.7%) smaller than P245/45R17

Because this reduction exceeds the ±3% threshold, P245/45R17 and P245/40R17 are not directly interchangeable. The shorter sidewall reduces ride height and increases wheel rotation frequency, which affects speedometer accuracy and changes ride and handling balance.

Difference Between P245/45R17 and P255/45R17

The P255/45R17 is wider and slightly taller:

• Width: P255/45R17 is 10 mm wider than P245/45R17
• Overall diameter: P255/45R17 is ≈0.35 inches (≈1.4%) larger than P245/45R17

Since the diameter difference remains within the ±3% range, P255/45R17 and P245/45R17 are generally compatible from a rolling-diameter standpoint. The practical change comes from the added section width, which can affect rim-width compatibility, inner clearance, and outer fender space.

Fitment Note for P245/45R17

In P245/45R17 applications, the ±3% diameter rule is only one part of the evaluation. Proper substitution also requires checking load index, inflation pressure requirements, approved rim width, and available clearance before installation.