You're at the trailhead. Phone in one hand, deflator in the other. Googling "what PSI for sand" for the fourteenth time this year. Meanwhile your buddy is already aired down and halfway to the first obstacle.
This is the chart you screenshot once and never google again. I'm giving you specific numbers by vehicle weight class, terrain type, and tire size -- because "lower your pressure" isn't a recommendation. It's a fortune cookie.
Before we get into the weeds: 20 PSI.
If you're new, if you're unsure, if you forgot everything in this article -- start at 20 PSI. It's the baseline that works for most vehicles on most terrain. It's low enough to make a real difference and high enough that you're not risking anything.
From there, adjust based on what's below.
These percentages are based on your highway pressure (typically 32-38 PSI for most trucks and SUVs):
| Terrain | Drop From Highway PSI | Example (from 35 PSI) |
|---|---|---|
| Gravel / Fire Roads | ~25% | 26 PSI |
| Rocky Trails | 30-35% | 22-24 PSI |
| Mud | 30-40% | 21-24 PSI |
| Snow | 25-35% | 22-26 PSI |
| Sand | ~50% | 16-18 PSI |
Simple version: gravel gets a light drop, rock and mud get a moderate drop, sand gets the big drop. That's the framework. Now let's get specific.
Vehicles: Jeep Wrangler (2-door), Ford Bronco, Toyota Tacoma, Jeep Cherokee
These rigs have the advantage of being lighter, which means less stress on deflated sidewalls. You can run lower pressures more safely than heavier trucks.
| Terrain | Stock Tires | 33" | 35" | 37" |
|---|---|---|---|---|
| Gravel | 24-28 | 22-26 | 20-24 | 18-22 |
| Rock | 18-22 | 16-20 | 14-18 | 12-16 |
| Sand | 14-18 | 12-16 | 10-14 | 10-14 |
| Mud | 18-22 | 16-20 | 14-18 | 14-18 |
| Snow | 20-24 | 18-22 | 16-20 | 16-20 |
Vehicles: Toyota 4Runner, Jeep Gladiator, Ford F-150, Chevy Colorado ZR2, Jeep Wrangler (4-door Rubicon loaded)
The sweet spot for most overlanders and weekend warriors. Moderate weight means moderate PSI -- you can go low, but don't push it as far as the light rigs.
| Terrain | Stock Tires | 33" | 35" | 37" |
|---|---|---|---|---|
| Gravel | 26-30 | 24-28 | 22-26 | 20-24 |
| Rock | 20-24 | 18-22 | 16-20 | 14-18 |
| Sand | 16-20 | 14-18 | 12-16 | 12-15 |
| Mud | 20-24 | 18-22 | 16-20 | 16-18 |
| Snow | 22-26 | 20-24 | 18-22 | 18-20 |
Vehicles: Toyota Land Cruiser, Ford Raptor, Rivian R1T/R1S, Ram Power Wagon, full-size trucks with bed weight
Heavy vehicles -- especially EVs with battery weight -- need to be more conservative. More vehicle weight on a deflated sidewall means more stress, more heat, and more risk of bead separation.
| Terrain | Stock Tires | 33" | 35" | 37" |
|---|---|---|---|---|
| Gravel | 28-32 | 26-30 | 24-28 | 22-26 |
| Rock | 22-26 | 20-24 | 18-22 | 16-20 |
| Sand | 18-22 | 16-20 | 14-18 | 14-16 |
| Mud | 22-26 | 20-24 | 18-22 | 18-20 |
| Snow | 24-28 | 22-26 | 20-24 | 20-22 |
EV note: Rivians and other electric off-roaders carry an extra 1,000+ lbs of battery. Stay toward the higher end of the heavy rig ranges. Don't go below 18 PSI on sand without beadlocks.
Tire load range changes everything. E-rated tires have stiffer sidewalls than C-rated tires. An E-rated tire at 22 PSI might flex like a C-rated tire at 28 PSI. If you're running E-rated, don't be afraid to go a few PSI lower to get the flex you want.
Bigger tires can run lower. A larger tire has more air volume. More volume means the same PSI represents more total air, which means more sidewall support. That's why 37s can safely go lower than stock tires at the same vehicle weight.
Never go below 10 PSI without beadlocks. The bead needs air pressure to stay seated on the rim. Below 10 PSI on a standard wheel, you're gambling. Hard turns, rock ledges, or throttle can pop the tire right off the rim.
Match all four tires. Within 1 PSI of each other. Uneven pressure means uneven traction, and that means unpredictable handling. Take the extra minute.
That's it. No apps, no calculators, no tire-nerd debates. Just a number, a gauge, and a few minutes at the trailhead.
The chart gets you to the right number. A MORRflate system gets you there in a fraction of the time -- all four tires at once, matched perfectly, deflation and inflation through the same kit. It's the fastest way to go from highway to trail and back again.
Check out the full lineup at morrflate.com.
Screenshot this. Save it. Stop googling. More off-road fundamentals at airdownforwhat.com.