Trail & Recovery

Airing Down Calculator

Get evidence-bounded off-road pressure ranges for sand, rock, mud, and trail driving.

Written by D.J. Montgomery Last updated August 9, 2026

Tire Size

Metric (285/75R16) or inch (35x12.50R17)

Fitted Tire Application

Enter the fitted tire's service/application marking, including single-tire use.

Manufacturer Table Reference

Identify the exact load/inflation table and source page or section confirming any already-adjusted capacities.

Table Tire Size

Table Tire Application

Load Table (PSI, capacity per tire in lbs)

Copy at least two discrete rows from the manufacturer table.

Verified Vehicle Application

Confirm the application with the vehicle manufacturer; do not infer it from weight alone.

Verified Tire Service

Confirm from the tire and its source documentation, including sizes without a service prefix.

Source Capacity Basis

Already-adjusted applies only to passenger tires in a light-truck application and must be explicit in your source.

Loaded Trip Weight (lbs, fallback)

Used only when both measured axle totals are blank.

Verified Front Cold-Pavement Pressure (PSI)

The placard is usable only for matching OE fitment; replacements need a verified adjusted value.

Verified Rear Cold-Pavement Pressure (PSI)

Enter the road pressure verified for this rear axle and fitted tire.

Front Weight Distribution: 48% front

Most trucks and SUVs sit close to 48% front. Only move this if you've weighed each axle.

Measured Front Axle (lbs, optional)

Measured Rear Axle (lbs, optional)

This calculator supports two tires per axle, not dual-wheel axles.

Maximum Trail Speed (mph)

Expected maximum while aired down, not highway speed.

Terrain Type

🏖️ Sand 🪨 Rock 🌿 Mud 🪵 Gravel/Trail

Terrain Guidance Reference

User-Sourced Terrain Target Low (PSI)

User-Sourced Terrain Target High (PSI)

This is your guidance interval, not manufacturer load evidence.

I have beadlock wheels (wheel-retention context)

Stock wheels are not beadlock. Only check this if you've installed aftermarket beadlock rings; beadlocks do not lower the load-table floor or waive the speed rule.

Gear for this calculator

Best Deflator

MORRFlate Quad Deflators

Deflates all 4 tires in under 5 min · PSI target lock

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Best Compressor

ARB Twin Air Compressor

On-board or portable · 4x4 proven

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Beadlock Wheels

Method Race Wheels 105 Beadlock

Forged beadlock · Fits most rigs

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The Physics of Airing Down

Formula

Per-tire load = axle load ÷ 2
Table comparison load = per-tire load × 1.10 for unadjusted passenger-tire capacities in light-truck use; otherwise per-tire load
Load floor = lowest listed pressure whose source capacity supports the comparison load
Supported range = overlap(load floor, your terrain guidance interval, each axle's verified cold-pavement ceiling)
Maximum off-road speed must be below 15 mph

Manufacturer load/inflation rows establish tire capacity only at the pressures they list. For each axle, the calculator divides the axle load by two and selects the lowest listed pressure whose source capacity supports the application-adjusted comparison load. Passenger-tire capacities in light-truck applications require a 1.10 adjustment: the calculator compares raw capacities against per-tire load multiplied by 1.10. If the source explicitly already divided capacities by 1.10, it does not adjust them again. LT tires and passenger-car applications use the unadjusted per-tire load. No comparison values are rounded. It preserves the authored rows, rounds up to the next supporting row, and never interpolates or fills gaps.

The selected load floor is intersected with your sourced terrain guidance interval and each axle's verified cold-pavement ceiling. The terrain interval is user-supplied guidance, not manufacturer load evidence. There is no universal pressure: tire construction, load, wheel fitment, terrain, temperature, and driving inputs all matter.

Measured axle totals assume equal left/right loading; an estimated vehicle-weight split is lower-confidence and should be verified on a scale. Corner-scale data can identify the heavier wheel-position load when available. This calculator assumes exactly two tires on each axle and does not support dual-wheel configurations.

This calculator is limited to off-road operation with an expected maximum speed strictly below 15 mph. Beadlocks are wheel-retention context, not load evidence, and they do not waive that envelope. A placard is usable only for matching OE fitment; replacement tires need verified adjusted cold-pavement values. Treat every result as an evidence-bounded starting range, watch for tire or wheel warnings in the field, and reinflate to the verified front and rear road pressures before pavement.

Terrain factors to document

Record a guidance source and interval for the actual route; this site does not publish a fixed terrain-pressure table.
Terrain context	Factors to document	Operating note
Soft sand	Load, flotation needs, wheel retention, and route guidance	Stay within the entered table, user-sourced interval, and speed envelope.
Rock crawling	Impact hazards, sidewall exposure, wheel fitment, and route guidance	Inspect for hazards and verify the guidance source applies to the setup.
Mud	Tread, load, recovery plan, and local guidance	Conditions can change quickly; verify before proceeding.
Gravel / dirt roads	Surface, heat, load, and road-pressure plan	Reinflate to verified road pressures before pavement.

How to source an interval

Use setup-specific documents, not a generic terrain number

First identify the exact fitted tire size and application, then copy rows from its matching manufacturer load/inflation table. Explicitly confirm the vehicle application, tire service, and whether the source already applies the passenger-to-truck capacity adjustment; matching dimensions across different size designations are not matching table evidence. Enter measured axle totals when available, or label a loaded-trip estimate. Separately record a terrain guidance source and its interval for the planned route, along with verified front and rear cold-pavement pressures.

The calculator selects the lowest authored load row for each axle and intersects it with the user-sourced interval and each axle's road-pressure ceiling. This is a table lookup and range intersection, not a universal safe setting.

Frequently Asked Questions

What PSI should I use for sand?

Use a setup- and route-specific guidance source for your terrain interval. The result is bounded by the entered load table and verified front/rear cold-pavement pressures; there is no universal sand pressure.

What PSI should I use for rock crawling?

Use a route-specific guidance interval only when the entered manufacturer rows support the axle loads. Account for wheel fitment, sidewall hazards, terrain, and speed. Beadlocks do not prove load capacity.

Can I air down without a portable compressor?

Carry a compressor or know where you can reinflate. Airing-down results are for off-road use; reinflate to verified front and rear road pressures before pavement and follow tire and wheel maker guidance.

What is tire load range and why does it matter?

Use the exact manufacturer load/inflation table for the tire size entered. The calculator selects the lowest authored pressure row that supports the axle load after any required passenger-to-truck capacity adjustment; it does not infer capacity from a generic load-range label or fill gaps between rows.

Does airing down affect fuel economy on the highway?

Off-road pressure is not a highway recommendation. Reinflation to verified front and rear road pressures before pavement helps return to the intended operating condition; follow tire-maker guidance for heat, load, and speed.

What tire pressure should I run in mud?

Treat a sourced mud interval as terrain guidance only: the entered load table, verified cold-pavement pressures, wheel fitment, temperature, speed, and conditions bound the result.

How low can I air down without beadlocks?

This calculator is limited to an expected maximum off-road speed below 15 mph. Beadlocks are wheel-retention context, not load evidence, and do not waive that speed envelope. Check tire and wheel guidance and reinflate before pavement.

Do I need to air down for gravel and dirt roads?

Use a local or route-specific guidance interval rather than a generic gravel number. Use the calculator's intersection only as evidence-bounded off-road starting guidance, and reinflate to verified road pressures before pavement.

Sources & references

Michelin load and inflation tables — match the exact tire and table, use measured axle-end loads when available, and hold one pressure across an axle based on the heavier end.
Goodyear inflation bulletin — explains why sidewall maximum is not the correct operating pressure and why replacement sizes require load/inflation-table data.
USTMA tire care and service manual, page 34 — requires passenger-tire capacity to be divided by 1.10 for light-truck applications. This adjustment does not establish replacement suitability.
BFGoodrich tire FAQ — provides the off-road, below-15-mph context for sub-20 PSI operation, while retaining the requirement for adequate load capacity.
BFGoodrich off-road guide — explains why there is no universal airing-down number and why tire, terrain, vehicle weight, temperature, and bead retention matter.

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Airing Down Calculator

Airing Down Results

The Physics of Airing Down

Terrain factors to document

How to source an interval

Frequently Asked Questions

Sources & references

Embed this calculator on your site

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