How long does it take to inflate a 275/55R20 tire?
A 275/55R20 tire (about 31.9 inches tall) holds roughly 73 liters. Raising it from 30 to 35 psi takes about 1 min 47 s with a compact 12V or cordless inflator, and filling it from flat to 35 psi about 12 min 27 s, or 4 min 35 s with a heavy-duty compressor.
VIAIR 85P/00085 Portable Tire Inflator, 12V Air Compressor for Cars & SUVs
A heavy-duty inflator suits a 73 liter tire: it moves enough air to fill one without overheating.
How long for each inflator class?
Times for one 275/55R20 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 | 25 L | 1 min 47 s | 1 min 8 s | 39 s |
| Top up 25 to 35 psi | 50 L | 3 min 33 s | 2 min 16 s | 1 min 19 s |
| Low tire 15 to 35 psi | 100 L | 7 min 7 s | 4 min 32 s | 2 min 37 s |
| Flat 0 to 35 psi | 174 L | 12 min 27 s | 7 min 55 s | 4 min 35 s |
What do the numbers in 275/55R20 mean?
275 is the section width in millimeters. 55 is the sidewall height as a percentage of the width, here 151mm. R20 means radial construction on a 20 inch rim. Together they give an overall diameter of about 31.9 inches and an internal volume of about 73 liters, which puts it in pickup and large SUV territory where inflator size matters.
Check pressure cold, before driving. All four tires from 30 to 35 psi take about 7 min 7 s with a compact unit.
Inflators and a gauge for 275/55R20 tires
Prices change often.
Nearby tire sizes
Frequently asked questions
What is the air volume of a 275/55R20 tire?
About 73 liters, estimated from the sidewall size: 275mm wide, a 55 percent sidewall (151mm) and a 20 inch rim. To add 5 psi you pump in about 25 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 275/55R20 tire?
Yes, but slowly: a flat 275/55R20 takes about 12 min 27 s with a compact unit, which is past the roughly 10 minute duty cycle many are rated for, so you may need a cool-down break. A heavy-duty 12V compressor does it in about 4 min 35 s without stopping. Always inflate to the door-jamb placard, not the sidewall maximum.
How much does a 275/55R20 tire lose in cold weather?
Like every tire, about 1 psi per 10 F drop. A 275/55R20 set to 35 psi at 70 F reads about 30 psi at 20 F. Put back the 23 liters of air it is missing when you check it on a cold morning.