145/80R17 Tire Size

All You Need to Know About 145/80R17 Tires

The 145/80R17 tire is part of the temporary spare category, where dimensions are optimized to balance compact storage with usable load support during short-term operation.

145/80R17 defines a tire that is 145 mm wide, with an 80% aspect ratio and a 17-inch wheel diameter, resulting in an overall diameter of ≈26.1 inches and a sidewall height of ≈4.6 inches.

Compared to narrower spare sizes such as 135/80R17, the 145/80R17 increases section width, which improves load distribution across the contact patch. 

At the same time, the 145/80R17 overall diameter remains slightly below larger spare formats like 135/90R17, which means rotational differences are still present when installed.

Because of this combination - wider footprint but not maximum diameter - the 145/80R17 occupies a middle position within spare tire sizing, where load support improves but drivetrain mismatch is not fully minimized.

145/80R17 Size Quick Specs

• Approved rim width range: 4.0-5.0"
• Typical inflation pressure: ≈60 PSI
• Overall diameter: ≈26.1"
• Section width: 145 mm
• Sidewall height: 116.0 mm
• Fits: 17-inch wheels (temporary spare applications)

Note: The calculated overall diameter of 145/80R17 is ≈26.1 inches. Actual mounted values typically vary within ±0.1–0.2 inches, depending on casing design.

145/80R17 Dimensions in Inches

The 145/80R17 tire is approximately 5.71 inches wide, 26.1 inches tall overall, and has a sidewall height of about 4.6 inches.

At ≈26.1 inches in diameter, the 145/80R17 circumference is ≈ 82.1 inches, which defines the rolling distance per full revolution. 

145/80R17 in Inches: All Measurements

• Overall diameter: ≈26.1"
• Width: ≈5.7"
• Sidewall height: ≈4.6"
• Wheel diameter: 17"
• Circumference: ≈82.1"

Circumference Difference of 145/80R17 vs Full-Size Tires

A 145/80R17 spare has a circumference of ≈82.1 inches, compared to ≈82-90 inches for most vehicles equipped with 17-inch wheels. This results in a rolling difference typically within 0-7.9 inches per rotation, or about 0-9.6%, depending on the original tire size.

Because 145/80R17 diameter is slightly lower than larger spare formats, the rotational mismatch is not minimized to the same degree as 135/90R17. However, it remains significantly closer to full-size tires than compact spares such as 125/70R17.

Axle Placement Requirements for 145/80R17

The 145/80R17 spare should be positioned away from the driven axle whenever possible.

On front-wheel-drive vehicles, 145/80R17 installation on the rear axle reduces continuous speed variation within the differential. On rear-wheel-drive vehicles, placing it on the front axle serves the same purpose.

Even with a ≈26.1-inch diameter, the difference in rolling circumference of the 145/80R17 tire compared to the remaining tires requires ongoing drivetrain compensation. Correct placement limits the mechanical load created by that mismatch.

145/80R17 Inflation Pressure Requirements 

A 145/80R17 temporary spare typically operates at approximately 60 PSI.

The increased width (145 mm vs 135 mm) provides a larger contact patch, but this does not eliminate the need for high internal pressure. The 145/80R17 tire still relies on pressure to support vehicle weight due to its compact construction.

If pressure in a 145/80R17 spare falls below the specified level, the casing can no longer support the load correctly, increasing sidewall deflection and internal heat. Keeping it at the recommended pressure is required for safe temporary operation.

Most Recommended 145/80R17 Tires

Best tires in 145/80R17 size include: Falken FK-090