Towing · chassis & road

Tire pressure by load chart

The number stamped on the sidewall is pressure at maximum load capacity — not automatically the right PSI for your measured axle weight. Use a scale ticket plus the tire maker’s load/inflation table.

Active corridor: Montana · Wyoming · Idaho · Washington — case-by-case beyond.

Field notes

Underinflation relative to actual load is still the most common heat-and-failure path we see on corridor tire calls. Guessing “80 PSI because the forum said so,” or always running sidewall max, both miss the point: pressure follows measured load for that tire model and size.

Who this is for

Right place if you

Have (or will get) axle weights and need cold PSI from a real chart. Just changed cargo, batteries, or water habits. Soft sidewalls, cupping, or a TPMS that keeps dipping on one corner.

Maybe not yet if

You have never weighed the rig travel-loaded — start with weighing your rig. You need age/DOT date help — see tire aging.

Load first, then the chart

Every tire manufacturer publishes a load/inflation table for that specific tire model and size. Once you know actual per-axle weight from a scale ticket, divide by the number of tires on that axle (or axle group) to get per-tire load, then match that figure on the maker’s table. Do not invent a matrix from memory, and do not treat a neighbor’s PSI as yours.

Sidewall max is a limit

Max sidewall pressure is the pressure at the tire’s maximum rated load — a ceiling, not a default. Running max forever when your measured load is lower can ride harsh and still be the wrong answer for that axle.

Cold only

Set and check when tires are cold — before driving, or after several hours parked. Hot tires read high; bleeding a hot tire down to your cold target leaves you under once it cools.

Duals and tandems

Uneven duals or a hot single on a tandem pair often show up as one tire carrying more than its share. Measure, then adjust cargo before you chase a “mystery” low tire.

TPMS honesty

TPMS catches slow leaks on the road. It does not replace a cold gauge check against the chart after a weigh or a big cargo change. Pair with tires, TPMS & brakes.

Owner checklist

Weigh travel-loaded; photograph the ticket and every tire/axle placard
Identify the exact tire model/size on the sidewall
Pull the manufacturer load/inflation chart for that tire — not a generic blog table
Set cold PSI from measured per-tire load; recheck after the first heat cycle without bleeding hot
Re-weigh and reset after major cargo, battery bank, or water-habit changes

Failure modes we see

Forum PSI forever

Someone else’s chart or a round number from a Facebook thread. Your axle load and tire model decide.

Hot bleed-down

Adjusting on a sunny shoulder to “look right,” then driving home soft.

Never weighed

Door sticker max is not a substitute for a ticket. See the weighing guide.

Ignoring age

Correct PSI on a dry-rotted carcass still fails. Check DOT dates.

DIY vs book UMRT

Reasonable DIY

Scale ticket, maker chart, cold gauge, TPMS install per instructions, covers for UV when parked long-term.

Book us when

You want a sanity pass on ticket + placard photos before a long MT · WY · ID · WA run, suspect uneven dual loading, or need on-site inspection after a heat event. Prefer Text clear photos of the ticket, sidewall, and placard.

FAQ

Can I just run sidewall max?

Only if your measured load actually requires it per the maker chart. Max is not a lifestyle.

Where does the chart come from?

The tire manufacturer for that model/size — dealer, maker site, or the literature that shipped with the tire. We do not invent load matrices here.

What does a visit cost?

Trip $75 within 30 miles then $1.50/mi each way; labor ~$150/hr with 1-hour minimum / 30-minute increments; diagnostic $175 applied if you proceed.

Text first?

Yes — Prefer Text (616) 606-5277 with ticket and sidewall photos. Many owners only need a redistribution or chart read; some still need on-site.

Prefer Text Book a Service All guides

Pricing teaser

Trip fee $75 within 30 miles, then $1.50/mi each way. Labor ~$150/hr (1-hour minimum, billed in 30-minute increments). Diagnostic $175 applied toward repair if you proceed.

Credentials (text): Victron Professional Certified Installer · weBoost Authorized Installer · Peplink Certified Associate · Dometic Professional Certified. Starlink = installs only (not a certified partner title).