How Much Air Pressure Should Be in a Spare Tire

Direct Answer and Scope

The correct air pressure for a spare tire depends on the type of spare installed. A compact temporary spare, often called a donut, commonly requires 60 psi. A full-size spare typically matches the vehicle manufacturer's recommended pressure for the regular road tires, which is often between 30 and 36 psi for passenger cars, but can be higher for trucks or heavily loaded vehicles. The most reliable source is the tire information placard on the driver's door jamb or the spare tire sidewall.

Compact Temporary Spares

Compact temporary spares are smaller, narrower, and lighter than regular tires. Because of their smaller air volume and reinforced construction, they require a high inflation pressure to support the vehicle's weight safely. The standard specified pressure for many compact spares is exactly 60 psi. Some older models or different designs may specify a slightly different value, but 60 psi is the dominant specification across most passenger vehicles.

A compact spare at normal passenger tire pressure, such as 32 psi, is underinflated. Underinflation causes excessive sidewall flex, heat buildup, poor vehicle stability, and possible damage to the spare wheel. Check the pressure with a reliable gauge before installing the spare. Do not rely on visual inspection because a compact spare can look round and firm while being severely underinflated.

Full-Size Spares

A full-size spare is a regular road tire, either mounted on a matching wheel or a steel wheel. Its correct pressure is the same as the vehicle manufacturer's specification for the other tires on the same axle. For most passenger cars and crossovers this is between 32 and 36 psi. For pickup trucks, vans, or vehicles carrying heavy loads, the recommended pressure may be 40 psi, 50 psi, or even higher depending on model and tire size.

Even if a full-size spare is not rotated into regular use, its pressure drops over time through normal air permeation and temperature changes. A spare stored at 35 psi in summer can measure below 30 psi in winter. Check and adjust it whenever you check your regular tires.

Where to Find the Specification

The primary source is the vehicle tire information placard, usually located on the driver's side door jamb, door edge, or inside the fuel filler door. The placard lists cold inflation pressures for front, rear, and spare tires. The vehicle owner's manual also contains a tire pressure section with the same values.

The spare tire sidewall shows a maximum inflation pressure, not a recommended pressure. On a compact spare, this is often marked as 60 psi. On a full-size spare, the sidewall maximum may be 44 or 51 psi, which is the tire's structural limit and is generally higher than the vehicle manufacturer's recommended running pressure.

Cold Inflation Practice

Tire pressure specifications apply to cold tires, meaning the vehicle has been parked for at least three hours or driven less than a mile at moderate speed. Heat from driving raises internal air pressure. If you must inflate a warm tire, add a few psi above the cold specification and recheck when the tire has cooled.

Use Limits and After Use

A compact temporary spare is intended for temporary use only. Most manufacturers recommend a maximum speed of 50 mph and a limited distance, commonly around 50 to 70 miles. The high 60 psi pressure is designed for this short-range emergency role. After using a compact spare, return it to its specified pressure before stowing it again.

If the compact spare has been unused for many years, have its condition inspected for cracks, dry rot, or tread separation before relying on it. Even a correctly inflated but aged spare may not be safe.

Checklist

Compact temporary spare: typically 60 psi cold, verify on placard or sidewall. Full-size spare: match the vehicle placard for regular tires, commonly 32 to 36 psi for passenger vehicles. Check pressure with a gauge before every use and during routine maintenance. Inflate only when cold for accurate readings. Observe speed and distance limits for compact spares.