Heavy Haul Guide

Heavy Equipment Trailer TPMS: Lowboy & RGN Tire Monitoring

A lowboy trailer does not haul a couch. It hauls an excavator, a dozer, a crane, a load so heavy the trailer had to be engineered low to the ground just to clear the overpasses — and every pound of it sits on a set of tires that the driver cannot see and cannot reach without crawling under the deck. A heavy equipment trailer TPMS exists for exactly that reason: on a rig this loaded, a tire losing air quietly is not a flat to fix at the next exit, it is a machine worth hundreds of thousands of dollars riding on a tire that is about to come apart.

This guide covers the trailers that move heavy equipment — lowboys, RGNs, and step decks — and how to monitor every tire on them, from the inner duals to the rear axle. If you just want the sizing answer: a four-axle lowboy is sixteen tires, a 22-wheel system covers it with room to spare, and the same system scales up to a 36-wheel fleet when you add more equipment trailers to the yard.

1. What a Lowboy Is (and Why It Has So Many Tires)

A lowboy trailer is a specialized flatbed with a deck that sits low to the ground, so tall equipment — excavators, dozers, cranes — can be loaded without exceeding bridge clearance. An RGN (removable gooseneck) is the heavy-haul variant whose front neck detaches, letting the equipment drive straight onto the deck from the front. A step deck splits the difference with a lower front and a higher rear. What they share is the thing that matters for tire monitoring: they are all multi-axle, dual-wheel trailers, running anywhere from three to five axles and sixteen to twenty-plus tires, because the load has to be spread across enough rubber to be legal on the highway.

That axle count is the whole reason monitoring is hard on these rigs. More axles mean more tires, more inner duals the driver cannot see, and a longer deck that puts the rear tires a long way from the cab. A system built for a car or a small RV simply does not have enough sensors or enough signal range to cover a lowboy — which is why the right tool for the job is a multi-axle lowboy trailer TPMS, not a repurposed passenger-car unit.

2. 3 Traits of Construction Tires That Change Monitoring

Heavy-equipment tires are not RV tires, and the difference changes what a monitoring system has to do:

• They run high pressure. Construction and heavy-haul tires run 100–130 PSI and up, far above the 50–80 PSI of an RV or utility trailer. A TPMS with a 0–200 PSI range covers them with headroom; a consumer unit that tops out near 100 PSI will alarm constantly or not work at all.
• They carry slow, extreme loads. A lowboy moves at a crawl with an excavator on the deck, and that low-speed, high-load condition generates heat differently than highway rolling. A monitoring system that reports temperature as well as pressure is what catches a tire cooking itself during a long, slow haul.
• They live in the dirt. Equipment trailers spend their lives on job sites — mud, gravel, sand, and standing water — not clean highways. Sensors need IP67 waterproofing and tough housings, or the job site retires them before the tires do.

3. Which Trailer Do You Run? Match It to a Kit

Here is the sizing table for the trailers that move heavy equipment, by axle count and wheel count:

The four-axle row is where most heavy-equipment haulers live: sixteen tires, which a 22-wheel kit covers with six positions to spare. If you run several trailers or a multi-axle heavy-haul setup, the 36-wheel kit covers the whole yard under one monitor. For a broader look at how the system stacks up against the field, our semi truck TPMS buyer's guide has the full comparison.

Built for Heavy Haul

GRUNDIG 550S Solar Powered TPMS — 22-Wheel Kit

• 22 sensors cover a 4-axle lowboy (16 tires) with 6 to spare
• 0–200 PSI range reaches the 100–130 PSI construction tires run
• Pressure and temperature alerts for slow, heavy hauls
• Signal booster included for the long lowboy deck
• IP67 sensors + solar monitor built for the job site

View the 22-Wheel Kit →

4. 22 Wheels for a 16-Tire Rig: The Multi-Axle Answer

The reason a 16-tire lowboy wants a 22-wheel system, not a 16-wheel one, is headroom. A lowboy's tires are not all the same age or in the same condition, and heavy haulers replace them one axle at a time as the job site takes its toll. The spare matters, the second trailer matters, and the inner duals — the tires you cannot see and cannot easily reach — matter most of all. A multi-axle TPMS that reports every position, inner and outer, is the difference between catching a leak on the far trailer axle and discovering it when the tire lets go under a hundred thousand pounds of machine.

For many equipment haulers, the trailer is not a fixed partner — it is a rotating cast. An operator may run a four-axle lowboy one day, a step deck the next, and a flatbed the day after, all behind the same tractor. That is where a single multi-axle system earns its keep: the sensors live on each trailer, the monitor lives in the cab, and the booster bridges the gap between them. Hook a different trailer and the display reads its sensors without reprogramming, so the same 22-wheel monitor covers whatever is behind you today — and a 36-wheel kit covers the largest combination in the yard. The trailers also sit idle between jobs, and idle tires lose air on their own over weeks of sitting. A monitor that reads all the tires the moment the rig powers up catches a winter's worth of slow loss before the loaded lowboy ever reaches the highway, which is exactly when a low tire would otherwise become a blowout.

When the load is measured in tons, the tires that carry it deserve to be watched on every axle, not just the ones you can see.

5. Mud, Dust & Heat: Monitoring That Survives the Job Site

A lowboy's working life is spent where the roads are not roads: muddy job sites, gravel staging areas, and sand lots, in heat and rain and salt. That environment is hard on electronics, which is why the specs that matter on an equipment trailer are different from the ones that matter on a motorhome. The 550S's sensors are IP67 waterproof and dustproof, with user-replaceable batteries rated for about two years, so a sensor that survives the season can be kept alive with a coin-cell swap instead of a replacement. The monitor runs on solar with a Type-C backup, so there is no wiring to run along the trailer and no charging routine to forget when the trailer sits in the yard between jobs.

6. Add a Backup Camera for the Lowboy Hook-Up

Loading a lowboy is an exercise in precision — driving a dozer onto a deck with inches of clearance, then backing the loaded rig out of a job site with no room to spare. A wireless backup camera with a magnetic mount drops onto the trailer's rear or the gooseneck area in minutes and feeds a 7-inch monitor in the cab, giving the driver eyes on the deck and the space behind it during the most precise moments of the job. The same philosophy as the TPMS applies: the things you cannot see from the seat are the things that cost the most when you get them wrong.

7. Frequently Asked Questions

8. The Bottom Line

Heavy equipment does not forgive a tire failure. A blowout under a loaded lowboy is not a flat to fix at the next exit — it is a hundred-thousand-dollar machine and its operator put at risk on the side of the road. A 22-wheel tire pressure monitoring system puts every axle of a four-axle lowboy on one screen — inner duals included — with pressure and temperature alerts and a booster that reaches the far end of the deck, in sensors tough enough for the job site. If you are still working out the exact sensor count for your rig, our sensor-count guide for 16+ wheel rigs has the math.

Disclaimer: Axle and tire counts vary by trailer configuration. Always count your actual wheel positions and match the system to your tires' pressure ratings and the manufacturer's installation instructions. A TPMS is a monitoring aid and does not replace pre-trip inspections or regular tire maintenance.