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.
Don’t ride on mismatched trailer tires. (image: iRV2 member drfife)
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.
Do your load ranges match? (image: LiveWorkDream.com)
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 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.
See also: How To Avoid The Dangers Of An Overweight Trailer
Rene Agredano and her husband, Jim Nelson, became full-time RVers in 2007 and have been touring the country ever since. In her blog, Rene chronicles the ins and outs of the full-timing life and brings readers along to meet the fascinating people and amazing places they visit on the road. Her road trip adventures are chronicled in her blog at LiveWorkDream.com.
Picture is of a Belt Separation and not a Run Low Sidewall Flex Failure.. Two different conditions with two completely different causes.
Passenger car tires are almost all “Load Range” B but cars do have specified inflations shown on the door jam placard. Your RV also has a tire placard. Motorhomes have it near driver seat. Trailers on outside, driver side toward front. It has important safety information on tire size and Load Range plus minimum inflation. Trailers almost always should be running the tire pressues molded on the tire sidewall associated with the max tire load capacity. If you look you will see that the sticker shows that same pressure.
I’m wanting to replace the Westlake tires on my 2014 Wildcat 317Rl with a GVWR of 13,769. Considering the Saliun, Goodyear and Maxxis. Tire size is 235/80/R16E. Which brand would you recommend?
One word SAILUN.
Sailun is made by the same company that makes Towmaxx.
Which plant is that?
NO ONE TALKED ABOUT AIR PRESURE, TIRES ARE MOSTLY RATED AT 44 PSI. WHICH IS A LOT, HOW MUCH LESS IS THE RATING AT SAY 35 PSI ??? DOES 20% LESS AIR RESULT IN 20% CAPICITY?
Lower pressure increases internal friction. Add a very hot road and speeds a little high, and a blowout is possible even when the load rating seems okay.
Max sidewall pressure reduces rolling resistance. This also reduces tire footprint on pavement (to optimum?).
I’ve pulled a new-to-me trailer with junk tires (4 different mfg’s, 3 sizes, one studded) home empty. I stopped immediately to air-up and check lights, and kept my speed as low as was safe on the road. It was dark and cool, so every chance was on my side. My local tire shop had 4 low-miles matching correct trailer tires to install that weekend.
44 psi is Passenger tire. LT and ST (Light Truck and Special Trailer) tires have higher “Load Range”
LR-C is 50 psi
LR-D is 65
LR-E is 80
and truck tires are higher.
You can learn some facts about tires in R application on my blog http://www.RVTireSafety.net
I am an RV owner and retired Tire Design Engineer (40 years)
As explained earlier, if your tires have a maximum inflation pressure they are probably not specifically for light trucks, trailers, or commercial vehicles… and you will have trouble finding information about how load capacity varies with inflation.
For LT, ST, and commercial tires the manufacturers publish “load/inflation” tables – following industry standards for the tire type – which show the load capacity at various pressures. Don’t use some rule of thumb or formula- look it up in the tables.
I carry an “AIR BOSS” compressor to maintain the specified PSI (and check the COLD PSI frequently). I also keep a torque wrench in my travel trailer tool bin, so I can check the lug nut torque (you can look that up on line or in your owners manual (different wheel sizes and travel trailer weight, have different lug nut values).
New tires aired up right will get you a long way down the road. However, the best way to get the most out of your tires is to match the air pressure to the load on each individual tire. Michelein tire chart for your size tire will give you the best scenario for your individual situation. But to get even more mileage out of your tires, balance them. When reinstalled they will be out of balance slightly, but enough to cause wear. I installed centro matic wheel balancers in 2013. They were installed on new Dextero LT 225/75R 16 tires. Air pressure @ 42#. [Recomended by Michelin tire chart.]. I have over 60,000 miles on them. I have six tires on a 2001 34’ Airstream. There is 8620#s on 6 tires, that means 1436# per tire. The reason for such low pressure for each tire.
Incorrect. Tire companies advise that all tires on an axle should have the same pressure. If you are selecting the pressure based on the measured load then you would use the load on the heaviest end of an axle. If you don’t know the actual load on each end of an axle then you should assume that one end is loaded to at least 53%.
When reading charts, especially Michelin, be sure you know if the numbers are per tire, per axle end or per axle… Michelin chart is correct for the Michelin brand which has slightly different numbers than the rest of the industry.
You missed another very important consideration – age. Most trailer tires never wear out their tread, they get old and rot and crack and generally become more prone to failure. I tend to lean towards a 5-7 year replacement schedule. Age is even more of a concern if they are running at or near capacity, and/or are under-inflated. I always run my trailer tires at their max pressure…less heat generated and less rolling resistance.
Another thing to consider – many tire shops don’t see the need to balance trailer tires. I’m not sure why you wouldn’t want to balance them…seems to me you’re just going to try to shake the poor trailer apart! I always make sure mine get balanced…
Maxxis ST tires are recommended for 3/4 and 1 ton trucks? NOT. ST tires are not legal on anything but a trailer. LT tires are for trucks and are a better choice for trailers. Myself and many others have upgraded to LT tires on our trailers with great success. Don’t fall for the ST hype.
A few years ago the tires on my 5th wheel were 5 years old. I took the RV to Camping World and asked them to check the tires. They said they were still good. On my very next trip I had a blowout on the RV. Needless to say, when the tires are 5 years old, I replace them now!!
This thread starts off with misleading information. Tire failures do not occur simply because you may have different Load Range tire on a different position. Tires fail because they do not have the proper inflation for the application (trailer vs motorized vehicle) or improper for the actual load.
As a retired tire design engineer, I suggest you read my RVTireSafety.net blog to learn the facts.