How Long Does It Take to Air Up After a Trail Run?
The honest range
Anywhere from about two minutes a tire to well over five, depending almost entirely on your compressor and your tire size.
Published testing on a 38-inch tire going from 12 psi to 31 psi put a 1.66 CFM compressor at 4:18 per tire and a 6.16 CFM twin at 2:13 per tire. Multiply by four: roughly seventeen minutes versus nine.
On smaller tires — the 31s and 33s most 2nd gens run — both numbers come down, but the ratio between a slow compressor and a fast one stays about the same.
What actually drives the number
CFM at pressure, not the headline CFM. Output falls as tire pressure rises, so the last few psi always take longer than the first.
Duty cycle. A compressor that has to stop and cool adds dead time that does not show up in any per-tire figure.
How far down you aired. Coming back from 8 psi takes considerably longer than coming back from 20.
Tire volume. A 33 holds meaningfully more air than a 31, and a 35 more again.
Ambient temperature. Compressors work harder and heat-soak faster in summer, which pushes duty cycle limits sooner.
Cutting it down
Three levers, in order of effect. Buy enough compressor — the single biggest factor, and the gap between a small unit and a twin is not subtle. Air all four at once with a four-line kit, which turns a sequential job into a parallel one, provided your compressor can feed it. Do not air down further than you need, since every psi you remove is a psi you put back.
There is also the option of simply not standing there. Hook up four lines, start the compressor, and go pack the truck, change out of muddy boots, or have a coffee. The job takes the same time and costs you none of it.
For which compressor suits which truck, our onboard air guide lays out the options.
