Load range letters (C, D, E, G…)  Indicate the tire’s ply rating and max pressure capacity — never downgrade load range from what the manufacturer specified, even if the tire size matches
DOT date code  The last 4 digits of the DOT stamp on the sidewall give week/year of manufacture — most RV tire manufacturers recommend replacement at 7 years regardless of tread depth, since sidewall rubber degrades with age even sitting still
Under-inflation  The single biggest cause of RV tire failure — a tire running even 20% under its rated pressure builds heat rapidly at highway speed and can fail catastrophically
Cold inflation pressure  Always check and set pressure before driving, not after — tire pressure rises as the tire heats up during a drive, so a post-drive reading isn’t your baseline
Weigh your rig loaded  Set tire pressure based on actual per-axle weight from a certified scale and the manufacturer’s load/inflation chart, not just the sidewall max

FIELD NOTE

RV tires often look fine visually right up until they fail — sidewall cracking (weather-checking) is the visible warning sign of age-related degradation, but a tire can fail from age before checking becomes obvious. When in doubt, the date code beats the tread depth gauge.

Sensor not reporting  Usually a dead sensor battery (most cap/valve-stem-mounted TPMS sensors use a 1–2 year replaceable or sealed battery) or a sensor not paired to the monitor after a tire rotation
False low-pressure alarms in cold weather  Tire pressure drops with ambient temperature (roughly 1–2 PSI per 10°F) — a real phenomenon, not a sensor fault, but worth setting your baseline pressure to account for it
High-temperature alarms  Take seriously — this is the leading indicator of a tire building toward failure, often before a pressure change is even noticeable
Internal vs. external TPMS  Internal (inside the wheel) sensors read actual tire temperature more accurately but require dismounting to service; external cap sensors are easier to install/swap but more exposed to road debris and theft

PRO TIP

A TPMS is an early warning system, not a substitute for physically checking tires before every trip. It tells you about a developing problem in real time on the road — it won’t catch sidewall weather-checking or age-related degradation sitting in storage.

How electric brakes work  An electromagnet inside each brake drum is energized by the tow vehicle’s brake controller, pulling the armature into the magnet and applying the brake shoes — proportional to how hard the controller tells it to
Time-based vs. proportional controllers  Time-based controllers ramp up braking on a fixed curve regardless of how hard you brake; proportional (inertia-sensing) controllers apply trailer braking proportional to the tow vehicle’s actual deceleration — proportional is the better-feeling, more common modern standard
Weak or no trailer braking  Check the 7-way connector pins for corrosion first, then brake magnet wear (they wear thin over tens of thousands of miles), then controller output setting/gain
Trailer brakes grabbing too hard or locking up  Almost always a controller gain setting too aggressive for the trailer’s weight, or uneven magnet wear side-to-side
Breakaway switch  A pull-pin safety device that applies full trailer brakes if the trailer separates from the tow vehicle — needs its own charged battery on the trailer and should be tested (pin pulled, brakes should lock) at the start of every season

FIELD NOTE

Brake magnets and shoes should be inspected annually and are a wear item, not a lifetime part — expect service around every 12,000 miles for magnets/shoes, sooner if you tow in hilly terrain or brake hard frequently. Uneven wear side-to-side is a common cause of pull during braking.