TPMS on Towables: The 2028 Mandate and What to Fit Now

It is not a mandate, and it does not apply to you.

That is the first thing to say clearly, because the phrase “2028 TPMS mandate” has entered circulation attached to the assumption that a federal law is coming and that owners of existing trailers will eventually have to comply with something. Neither is true. What happened is narrower, and understanding exactly what it is tells you a great deal about whether to fit a system to your own trailer — which, separately, you probably should.

What was actually approved

In March 2026, the RV Industry Association’s Board of Directors approved a program requirement that tire pressure monitoring systems be included on towable RVs beginning at the start of each manufacturer’s model year 2028 production. The requirement covers towable products under 26,000 pounds GVWR.

The mechanics matter:

• Rather than setting one industry-wide date, each manufacturer implements at its own model year changeover, so that every unit in that manufacturer’s MY2028 lineup is equipped.
• The requirement takes effect during calendar year 2027, as manufacturers begin building MY2028 units.
• RVIA inspectors verify compliance during normal inspection visits in 2027, tracking VINs and coordinating with manufacturers on changeover dates.
• Separately, the association’s Standards Steering Committee approved public inputs to add the requirement to the 2029 edition of NFPA 1192, the Standard for Recreational Vehicles. The proposed language requires a tire pressure and temperature monitoring system installed in accordance with SAE J3309, the recommended practice covering trailer TPMS for units under 26,000 pounds GVWR.

So: a trade association imposed a build requirement on its own members, ahead of the consensus standard it expects to adopt later, and enforces it through its own inspection program.

Why federal law does not cover your trailer

The federal TPMS rule, FMVSS No. 138, came out of the TREAD Act and requires tire pressure monitoring on new light vehicles — passenger cars, multipurpose passenger vehicles, trucks and buses with a gross vehicle weight rating of 10,000 pounds or less. When NHTSA developed the rule it did not propose extending TPMS to medium or heavy vehicles, and trailers have never been within its scope.

The practical effect is that the vehicle doing the pulling has been legally required to monitor its tires since the mid-2000s, while the vehicle carrying most of the weight, running the cheapest tires, and sitting outside the driver’s field of attention has not been required to monitor anything at all. That gap is what the industry has now moved to close, voluntarily, roughly two decades later.

You are not obligated to close it on your own trailer. You are, in my view, foolish not to.

Temperature is the point, not pressure

The most useful detail in the RVIA action is buried in the standard it references. SAE J3309 covers tire pressure and temperature monitoring, and temperature is doing more work here than pressure.

Trailer tire failures are overwhelmingly heat events. The sequence is consistent: a tire runs underinflated or overloaded, the sidewall flexes more than it should, flexing generates heat, heat degrades the bond between belts and carcass, and the tire comes apart — often at speed, often on the side you cannot see from the mirror. The pressure loss that started it may have been slow enough that nothing looked wrong at the last walkaround.

A pressure-only monitor catches the cause. A pressure-and-temperature monitor catches the cause and the consequence, and it catches something else that pressure alone will never see: a dragging brake or a failing wheel bearing. Both dump heat into the hub, and the tire temperature climbs before anything else gives you a symptom. For a tandem-axle trailer where a seized bearing is a genuine roadside-fire risk, this is arguably the more valuable alarm of the two.

Two contributing factors are worth naming because they are within your control. Overload is the first, and trailer tires are frequently asked to carry more than their rating because the trailer itself is loaded beyond its axle capacity — a problem that starts with misunderstanding what the tow vehicle and trailer are actually rated to carry, which we cover in towing capacity and why the sticker number is not your real limit. Sustained speed is the second: special trailer (ST) tires carry speed ratings that are lower than passenger tires, and running above the rating for extended periods generates heat the tire was not designed to shed. Check what your specific tires are rated for rather than assuming.

Should you fit one now?

Yes, for anything with more than one axle that travels meaningful distances, and the reasoning is not really about safety statistics. It is about asymmetry of cost.

A trailer blowout rarely stops at the tire. The failing carcass throws heavy rubber into the wheel well at speed and typically takes out some combination of the underbelly panel, fender skirt, sidewall trim, wiring, and plumbing runs in the area. Repair bills routinely reach four figures, and the trip is over. Against that, a monitoring system is a rounding error on the cost of owning the rig at all — a figure we itemise in full in our five-year cost of RV ownership breakdown.

This is also one of the quieter arguments in favour of a motorized rig over a towable, since a coach’s tires are already federally monitored and sit in front of the driver rather than behind — a trade-off we weigh in travel trailer vs Class B vs truck camper.

The case is weaker, though not absent, for a single-axle lightweight trailer that rarely leaves the region. On a single axle, a tire failure is immediately obvious to the driver, and the consequences of a slow leak are less likely to compound unnoticed. Even there, the low cost of entry makes it a reasonable purchase — see our comparison of off-road teardrops under 2,500 lbs for where light single-axle trailers sit generally.

How to choose a system

Ignore brand rankings. The meaningful choices are architectural.

Sensor type

External sensors are the sensible default for a retrofit. The one non-negotiable is that they should not be fitted to short rubber valve stems on wheels that see highway speeds — the added mass at the tip of a flexible stem is a failure mode of its own. If your wheels have rubber stems, budget for metal replacements at the same time.

Look for flow-through external sensors, which let you check and add air without unscrewing the sensor. The ones that must be removed to inflate get checked less often, which defeats the purpose.

Signal repeaters

The transmitter is at the back of the trailer; the display is in the cab. On longer rigs, or where a metal-sided trailer sits between the two, the signal needs help. Most manufacturers specify a length threshold above which a repeater is required, and repeaters typically need a permanent 12V feed. Read the specification for your combined length before assuming the base kit reaches.

If you get intermittent sensor dropouts after installation, the answer is almost always a repeater rather than a faulty sensor.

Display and integration

Three approaches:

• Dedicated monitor. A small display, usually suction-cupped or dash-mounted, sometimes solar-assisted. The most reliable, the least elegant.
• Phone app over Bluetooth. Fewer objects on the dash, but check whether the app must be open and in the foreground to alarm. A monitoring system that only alarms when you are looking at it is not a monitoring system.
• Integration with the tow vehicle’s factory TPMS. Some late-model trucks support adding trailer sensors to the vehicle’s own display. This is the cleanest result where it is available. Support varies by manufacturer and model year, and the RVIA requirement says nothing about how OEM trailer systems will communicate with tow vehicles — that remains unsettled.

Sensor count

Buy enough sensors for every trailer tire and the spare. A spare that has quietly deflated in its carrier over two seasons is a common and thoroughly avoidable discovery to make at the roadside.

Setting it up so it does not cry wolf

The most common reason people stop using a TPMS is nuisance alarms, and nuisance alarms are almost always a setup error.

Baseline at cold pressure. Set the reference to the cold inflation pressure specified on the trailer’s tire placard, measured before driving, not to whatever the tires read after an hour on the highway. Special trailer tires are generally run at the maximum cold pressure marked on the sidewall unless the placard says otherwise — confirm against your own placard rather than assuming.

Expect pressure to rise as you drive, and do not treat that as a fault. The rise is a gas law consequence: pressure increases roughly in proportion to absolute temperature. Working it through, a 10°F rise raises pressure by about 2% of the absolute pressure — roughly 1 psi on a 30 psi car tire, but closer to 1.8 psi on an 80 psi ST tire. A tire that starts at 80 psi cold and reads 88 psi warm on a hot afternoon has not developed a fault.

Set thresholds with that headroom in mind. Typical manufacturer defaults sit around 12–15% below baseline for the low-pressure alarm and 20–25% above for high pressure, with temperature alarms commonly in the region of 158°F (70°C). Treat those as starting points and follow the documentation for your specific system and tires rather than these figures.

Watch differentials, not just absolutes. One tire on an axle running consistently hotter than its neighbor is information even when neither has triggered an alarm. That is the bearing and brake signal, and it appears well before any threshold is crossed.

What changes for buyers in 2027 and 2028

If you are shopping for a new towable in that window:

• MY2028 units from RVIA member manufacturers should arrive with TPMS fitted. MY2027 and earlier units generally will not, and the changeover date differs by manufacturer.
• Ask which sensor type is fitted. An internal sensor with a sealed, non-replaceable battery is a future tire-shop visit that an external sensor is not.
• Ask what the display arrangement is and whether it integrates with anything, or whether you are getting a proprietary monitor.
• Do not pay a meaningful premium for the feature. The retrofit cost is low, which caps what factory fitment is worth.
• Registration, licensing and weight class requirements are a separate matter entirely and unaffected by this change — see our guide to RV and trailer registration, weight classes and licences.

Frequently asked questions

Is TPMS required on travel trailers? Not by federal law. FMVSS No. 138 applies to light vehicles of 10,000 lbs GVWR or less and has never covered trailers. The RV Industry Association has imposed a program requirement on its member manufacturers to fit TPMS to towables under 26,000 lbs GVWR from each manufacturer’s model year 2028 production, taking effect during calendar 2027.

Will I have to retrofit my existing trailer? No. The requirement applies to new manufacturing only. There is no retrofit obligation on owners at any level of regulation, and none is proposed.

Does the 2028 requirement have the force of law? Not on its own. It is enforced through RVIA’s membership inspection program. The related change proposed for the 2029 edition of NFPA 1192 could acquire legal force in jurisdictions that adopt that standard by reference, which is a state-by-state question and a later one.

Are internal or external sensors better? External sensors are easier to fit, cheaper, and allow battery replacement, but add mass to the valve stem and can be stolen. Internal sensors are protected and add no stem load but require tire dismounting to service. For a retrofit, external flow-through sensors on metal valve stems are the practical default.

Why does my TPMS alarm on hot days? Almost always because the low or high thresholds were set against a warm baseline, or set too tight. Pressure rises with temperature by roughly 2% of absolute pressure per 10°F, which is a larger absolute jump on a high-pressure ST tire than on a car tire. Re-baseline to cold placard pressure and widen the high-pressure threshold.