Mixing mix plaid shorts with a striped shirt won’t hurt you. But mismatched RV trailer tires can kill. A tire blowout is inevitable if you’re driving on improper RV trailer tires. Here’s why matching trailer tires and load range on all four is a matter of life or death.
Over the course of 12 months we had two RV tire blowouts. To pinpoint the cause we drove to Livingston Texas for a weigh-in at the Escapees RV Club’s professional-grade RV weigh scale. During our weigh-in I mentioned our two trailer tire blowouts to the scale weighmaster. She walked around our rig while examining each trailer tire. Then she returned the verdict. “This is probably why,” she said as she pointed out the source of the dangerous RV tire blowouts. “Your tires don’t match. You have three different load ranges on four tires.” Her answer caught us off-guard and we weren’t sure what she meant.
“They’re trailer tires,” I said. “Isn’t that good enough?” Apparently it wasn’t. She recommended buying all new trailer tires with the exact same load range. We wanted another opinion before spending the money so we turned to RV trailer tire expert Ron Russell. He owns the company that installed our electric over hydraulic trailer brakes.
Don’t pay the price of mismatched trailer tires and load range.
Russell kicked things off by illustrating the importance of rolling on a set of trailer tires with identical load range. He explained how the load range for passenger car tires isn’t as much of a safety issue as it is for RVs. Since most passenger vehicles are operated with a 20-30% reserve load capacity, they have ample room for extra cargo. On the other hand, most trailers travel while fully-loaded with zero reserve load capacity. The slightest amount of extra weight on just one tire can push it over the load range and cause a blowout.
All tires should have the same load range but don’t buy them until you know your RV’s GVWR (Gross Vehicle Weight Rating). You’ll find it in your owner’s manual or on a small metal plate mounted to the outside of your RV. Once you know your trailer’s GVWR, you want to buy a tire and wheel combination that exceeds your trailer’s GVWR by at least 20%. This amount is the tire’s “reserve load capacity” and it’s something you want plenty of.
Passenger car tire shops usually don’t carry good trailer tires. Most will special order trailer tires if you ask, but will try to sway you into buying popular brands carried by their distributors. Don’t buy until you talk to a professional RV tire expert who can recommend the proper tire brand, size, and load range for your needs.
We ordered a set of Maxxis 10-ply ST225/75R15 tires with a load range E. These tires are recommended for trailers, ¾ and 1-ton trucks. A passenger car tire shop ordered them at our request, then installed them in their parking lot. The $800 cost was steep but worthwhile. Our new tires have have heavier cord material, sidewalls, and bead wire than our previous ones. And now we tow with more confidence because we are towing with a 20-30% reserve load capacity. This small but expensive upgrade gives us peace of mind with better protection against scary, damaging trailer tire blowouts.