Thursday, March 3, 2016

Tire Inflation pressures for your RV trailer

Government and tire industry standards agree. The correct inflation pressures for your RV trailer tires are determined by it’s manufacturer and depicted on the Vehicle’s certification label, in it’s owner’s manual and on tire placards. They are called, “Recommended Cold Inflation Pressures”.

Normally - over 95% of the time - recommended inflation pressures for RV trailer tires are going to be the same as the maximum amount found on the tire’s sidewall. That leaves zero room for adjustments. OOPS, there is a way for adjustments to be made. Go to a good set of vehicle scales and see what the weight is for each wheel position on your trailer. Then use those findings to balance your cargo load so no tire is overloaded. It may require unloading things to your truck or just not carry them.

Replacement tires must provide the same or more load capacity than the Original Equipment tires. Replacements with excess load capacity by inflation can be adjusted up to the maximum load capacity shown on their sidewalls. But, you should still weigh your trailer and balance it’s cargo load.

Don’t be duped by recommendations to air your tires to the load carried. That’s what truckers do and you can see the results on our highways all across the country. The FMCSA has no provision for recommended tire inflation pressures. The inflation pressures for our RV trailer tires (any design) were set in motion by FMVSS. Don’t let those that want to use trucker regulations confuse the RV trailer tire inflation subject. What is good tire inflation for tractor-trailer tires is not good for RV trailer tires.

Bottom line: At replacement time get tires with 12% - 15% excess load capacity above your GAWRs

Tuesday, December 20, 2011

Why do so many trailer tires (ST) fail?

There is no clear answer, only speculation. Anecdotal information drives speculations into name calling and negative design confidence.
As everyday tire users we are spoiled. We don't suffer tire failures with our everyday vehicles. When we do they can almost always be accounted for. Most of us will go for many years without a single tire failure. Then we get an RV trailer and POP goes the tires.

The tires on our everyday vehicles are - in most cases - specifically designed for the vehicle they are on. They are quality graded for all sorts of conditions with tread designs to match the grading. Their load capacity has been derived from the maximum loaded vehicle with a 6% reserve left over which will seldom, if ever, be used. They are constantly in use so the built-in chemical compounds stay in action and degrading is held at the bare minimum. Most of them will wear out long before they will ever get old enough to be effected by degradation or age or both.

On the other hand the RV trailer also has tires specifically designed for their position. And that's where almost all of the similarity ends. Seldom has a tire design been scrutinized as often and with such detail as the ST tire. Almost all of the American manufacturers have given up on the trailer tire or have sent it to their off shore plants in faraway places like China, Vietnam, Korea, Taiwan or Thailand etc.

Most users that have had a ST tire failure or numerous ones are not going to like or agree with many of my analogies on this subject. The overwhelming evidence will support my stance but there are no official statistical findings to support what I say. But, logic always has a strong influence on many outcomes in the absence of other evidence.

In the absence of numerous recalls for the ST tire one must assume the design is sound and cannot, by itself, have caused the many failures reported against it.

Once the design is ruled out of the failure scenario  the cause must lie elsewhere. So, is there a single cause or a combination of causes? I like multiple causes over the single one. Of course any highly abused single cause can also be the culprit.

Here are my accusations. We overload our trailers. We speed with our trailers. We take a somewhat lackadaisical attitude about our trailer's tire pressures. We store our trailers for long periods of time - six months or more - with no regard for the tire's condition or pressures. The trailer may not even be level which causes tires on the low side to become overloaded for their entire time in storage. We don't balance or rotate the trailer tires. Sometimes the spare is
exposed to the elements for so long it explodes.