Accessories · inflators
Four minutes, or fourteen.
Six inflators, one tyre — a 245/50R20, let down to 10 psi and timed back up. The quickest reached 30 psi in 1:34. The slowest took 6:40. Carry that on to 45 psi and it is 2:47 against 13:15, which is the difference between a job and an ordeal at the side of a road.
A factor of four, on the same tyre
Scale runs to 400 s, the highest measured value here.
use it Car and Driver, Best Portable Tire Inflators of 2026, Tested, 17 February 2026. One tyre on one vehicle: a 245/50R20 on a 2023 Hyundai Santa Cruz, let down to 10 psi on a handheld gauge, then each inflator timed to 30 psi and again to 45 psi. Noise averaged in dBA and sone over 15 seconds of running. Each unit's own gauge was checked against the handheld one before and after.
4.3 times between the ends of that chart, on identical work. Rated psi, the figure printed largest on every box, does not appear in it — every one of these will eventually reach 45 psi. What differs is how long you stand there.
The number everyone quotes flatters small pumps
Both figures were measured, so the rate in each half can be worked out: seconds per psi from 10 to 30, then from 30 to 45. Air gets harder to push as pressure rises, and the two halves are not equally hard.
Scale runs to 1.67, the highest measured value here.
use it Car and Driver, Best Portable Tire Inflators of 2026, Tested, 17 February 2026. One tyre on one vehicle: a 245/50R20 on a 2023 Hyundai Santa Cruz, let down to 10 psi on a handheld gauge, then each inflator timed to 30 psi and again to 45 psi. Noise averaged in dBA and sone over 15 seconds of running. Each unit's own gauge was checked against the handheld one before and after.
That chart is our arithmetic over Car and Driver's two measured times, not a finding they publish. The sums are in the table below and you can redo them: seconds to 30 divided by 20 psi, against the remaining seconds divided by 15.
The Milwaukee barely notices the second half — 4.7 seconds per psi becomes 4.9. Everything else loses between a quarter and two thirds of its rate. So the industry-standard “time to 30 psi” is measured over the easy part, and a small pump looks closer to a big one there than it will be when you are actually topping up to 35 or 40.
If you want the answer for your own tyre rather than for a 245/50R20, we built a calculator that scales these times by tyre size.
What the weight actually buys
Weight is the price of speed here, but it is not paid evenly. Going from the 1.1 lb AstroAI to the 8.7 lb Milwaukee — 7.6 lb more — saves 306 seconds to 30 psi. Going to the 4.4 lb Slime instead, just 3.3 lb more, already saves 262 of those 306.
And weight alone does not buy it: the Viair at 5.6 lb reaches 30 psi in 1:44 while the Wolfbox at 5.0 lb takes 3:12. Same bag, nearly double the wait. It is the pump, not the mass.
Six inflators, as measured
| Product | To 30 psi from 10 psi use it | To 45 psi from 10 psi use it | Weight lb use it | Noise dBA use it | Hose as supplied use it | Where to buy |
|---|---|---|---|---|---|---|
| Milwaukee M18 2848-20 our pick Battery and charger sold separately | 1:34 | 2:47 | 8.7 | 87.3 | 36 in | Check on Amazon |
| Viair 88P Alligator clips to the battery. Analogue gauge | 1:44 | 3:54 | 5.6 | 79.9 | 16 ft | Check on Amazon |
| Slime Cordless Pro Power Half its charge gone after one 10–45 psi run | 2:18 | 5:09 | 4.4 | 78.0 | 30 in + 15 ft | Check on Amazon |
| Wolfbox Megavolt 24 Air Also a 24,000 mAh jump starter and power bank | 3:12 | 6:10 | 5.0 | 84.0 | 20 in | Check on Amazon |
| Avid Power pistol grip Battery or the car's 12 V outlet | 4:14 | 8:44 | 2.6 | 84.8 | 19.6 in | Check on Amazon |
| AstroAI L4 Fits in a glovebox. Hose is one foot long | 6:40 | 13:15 | 1.1 | 79.3 | 12 in | Check on Amazon |
use it Car and Driver, Best Portable Tire Inflators of 2026, Tested, 17 February 2026. One tyre on one vehicle: a 245/50R20 on a 2023 Hyundai Santa Cruz, let down to 10 psi on a handheld gauge, then each inflator timed to 30 psi and again to 45 psi. Noise averaged in dBA and sone over 15 seconds of running. Each unit's own gauge was checked against the handheld one before and after.
What nobody has measured
- Duty cycle. Four tyres in a row is the actual use case and nobody times it. One unit in this test was noted as having a ten-minute limit to stop it overheating; the rest are unstated.
- Gauge accuracy as a figure. The testers checked each unit's gauge against a handheld one and reported one as inaccurate, but no published error in psi exists for any of them.
- Cold. These were timed in a garage. A lithium pack at −10 °C is a different tool, and that is exactly when a tyre goes soft.