Tire Safety & Selection

RV tyres are not something people think about until a problem arises. That's the issue. Even if the tread looks good, the tire isn't healthy, properly loaded, or right for the RV, nor has it been sitting for years in the sun.

Tire safety is all about weight for motorhomes, fifth wheels and travel trailers. Not dry weight of brochure. Not based on how the rig "feels." Actual axle load and actual tyre load counts. After determining the loaded weight, you can make a pressure setting based on the tire manufacturer's load tables or the RV placard and select replacement tires that are truly suitable.

RoadReviewer Take

Three major RV tire pitfalls are running the tires under inflated, not taking into account the age of the tire, and assuming that the original RV tire size is the same as the current load. Although a TPMS is a great help, it is no substitute for weighing the RV, checking cold pressure, inspecting sidewalls and replacing tires before they become a trip ending situation.

Start with weight

All tyres are rated for a maximum load at a given pressure. All campers come with axle ratings. The more trips that are added, the more people, water, food, tools, bikes, batteries, solar equipment, cargo, and hitch weight. The only way to find out what the tires are loaded with is to weigh the RV when it is ready to travel.

Individual wheel position weighing is the best option. If not, axle weights are still the better option than guess work! After weights are loaded, check them against the axle ratings as well as the tire load ratings and inflation tables. Even if a trailer is under GVWR, there can be a side to side imbalance which causes the overloading of one tire.

Cold pressure matters

Tire pressure should be measured with tires cold, before driving or after parking the vehicle for a period of time that will allow the tires to cool. Typically the pressure molded on the tire side wall is the maximum pressure for the maximum load, and not a single operating pressure for all RVs. The RV placard and tire manufacturer's load tables are more helpful.

Heat is a tire enemy, and underinflation creates heat. Overloading has the same effect. An overloaded under inflated tire is asking to fail. That is exacerbated by hot weather, highway speeds and rough roads.

Tire age is real

RV tires tend to "wear out" before they age out. This is particularly the case for motorhomes, seasonal trailers and rigs that are left outside. Factors of aging are sun exposure, heat, storage conditions, low use and poor inflation. The DOT date code is a way of identifying the time of manufacture. If owners don't get to know it, they can't only use the tread depth.

While there is no universal age guideline that applies to all tires and all uses, many RV owners start thinking about replacing tires when they reach the five- to seven-year mark and take the tire manufacturer's advice. Once cracking, bulging, uneven wear, impact damage or recurring pressure loss is detected, then age is secondary. Replace the tire.

ST, LT, and motorhome tires

ST tires are usually employed on travel trailers and are designed for the service. Commercial type tires are frequently manufactured to fit motorhomes and are matched to the axle load, wheel size and speed rating. Some towables are equipped with LT tires as per design and manufacturer's requirements. It's not all about the letters! Full load capacity, speed rating, wheel compatibility, reality of operating conditions.

If the vehicles are equipped with tires that are less expensive or lower rated, the safety margin is eliminated. If the RV was already near the limit, the owner may wish to consult with a knowledgeable tire dealer about the larger capacity tires, but remain within the wheel and suspension limits.

Check the tires for signs of wear, punctures, or bulges.

Each month, tires should be checked for their pressure, irregular wear, cuts, bulges, valve stems and embedded objects, and sidewall cracking. Check not just the "easy" out side, but inside sidewalls as well. If axles are not properly aligned, suspension components are worn, or tires are not properly inflated, trailer tires can wear irregularly.

Valve stems are worth checking out. The same goes for extensions on the dual rear wheels. A leak at an extension can cause the same effect as a puncture. Metal valve stems are typically recommended for use when TPMS are added, but it should be the same as the wheel and sensor needs.

TPMS is not magic, it's useful.

One of the improved safety features for towables and motorhomes is a tire pressure monitoring system. Can alert driver to pressure loss or temperature change before driver is aware. However, a TPMS does not excuse neglectful or manual checks. It won't be able to tell you if it's aged out, overloaded, cracked or wrong.

Carefully set warning levels. Alarms need to be tight, or they won't do much good. If they're too loose, they might go unnoticed.

Storage habits

Keep tyres clean, at proper pressure, and shield from direct sunlight, if possible. Do not park for extended periods in water, mud or oil contaminated surfaces. If possible, relocate the RV from time to time. To reduce UV exposure, particularly in warm climates, tire covers may be considered.