How long does it take to inflate a 185/65R15 tire?
A 185/65R15 tire (about 24.5 inches tall) holds roughly 30 liters. Raising it from 30 to 35 psi takes about 43 s with a compact 12V or cordless inflator, and filling it from flat to 35 psi about 5 min 4 s, or 1 min 52 s with a heavy-duty compressor.
AstroAI Tire Inflator Portable Air Compressor, 12V DC/120V AC Dual Power
A compact inflator is enough for a 30 liter tire: top-ups take about 43 s.
How long for each inflator class?
Times for one 185/65R15 tire using delivered flow at tire pressure, which is roughly 40 to 50 percent of the rated figure on the box: about 14, 22 and 38 liters per minute for the three classes.
| Job | Air to pump | Compact | Fast cordless | Heavy-duty |
|---|---|---|---|---|
| Top up 30 to 35 psi | 10 L | 43 s | 28 s | 16 s |
| Top up 25 to 35 psi | 20 L | 1 min 27 s | 55 s | 32 s |
| Low tire 15 to 35 psi | 41 L | 2 min 54 s | 1 min 50 s | 1 min 4 s |
| Flat 0 to 35 psi | 71 L | 5 min 4 s | 3 min 13 s | 1 min 52 s |
What do the numbers in 185/65R15 mean?
185 is the section width in millimeters. 65 is the sidewall height as a percentage of the width, here 120mm. R15 means radial construction on a 15 inch rim. Together they give an overall diameter of about 24.5 inches and an internal volume of about 30 liters, typical of cars and crossovers, where any decent portable inflator copes.
Check pressure cold, before driving. All four tires from 30 to 35 psi take about 2 min 54 s with a compact unit.
Inflators and a gauge for 185/65R15 tires
Prices change often.
AstroAI L7 Tire Inflator Portable Air Compressor,150 PSI Cordless Bike Pump150 PSI / cordless$23.49Check price on Amazon
KeenPower Tire Inflator Portable Air Compressor 21V Battery Powered 160PSI160 PSI / cordless$53.79Check price on Amazon
Nearby tire sizes
Frequently asked questions
What is the air volume of a 185/65R15 tire?
About 30 liters, estimated from the sidewall size: 185mm wide, a 65 percent sidewall (120mm) and a 15 inch rim. To add 5 psi you pump in about 10 liters of free air, because each 14.7 psi of pressure equals one tire volume of outside air.
Can a small tire inflator fill a 185/65R15 tire?
Yes. A compact unit tops it up in about 43 s and fills it from flat in about 5 min 4 s, within the duty cycle of most compact inflators. Always inflate to the door-jamb placard, not the sidewall maximum.
How much does a 185/65R15 tire lose in cold weather?
Like every tire, about 1 psi per 10 F drop. A 185/65R15 set to 35 psi at 70 F reads about 30 psi at 20 F. Put back the 10 liters of air it is missing when you check it on a cold morning.