OK, so maybe the title is a bit too cute. But it was suggested I try to balance my focus on highly technical stuff with a little bit of lighter stuff. Well, air is light, isn’t it?😉
Today’s key points:
- Know the minimum tire inflation based on manufacturer estimates of the weight of the RV.
- Check your inflation with a good gauge at least monthly and every morning before travel.
These tire inflation posts are important
Tire inflation seems to be a topic that confuses some and has others believing in misleading or just plain incorrect information. Tire inflation is one item that directly affects the safety of your RV, truck or car as you travel down the highway. Many of my posts have been background information that you really don’t have to know or fully understand. The intent of these topics is to give you a better foundation of understanding more about tires, but if you only pay attention to one series of posts, this is it.
Tires do not carry the load. They are just a container of air. It is the inflating air that does the work. Think for a moment of an impact wrench. It can’t do the work of loosening or tightening nuts on your wheels without the air. A tire can’t do the work of carrying the load or provide the traction needed to turn, start, or stop if it doesn’t have air. The load a tire can carry is based on the air volume of the tire (tire size) and the pressure of that air inside the tire.
If you want to get a feel for how little load your tire can carry without air in it, you can test this yourself. Simply take an unmounted tire and stand on the beads of the tire. I think you will find that the tire can support less than 5% of the rated load before it deflects more than an inch or two, or even completely collapses.
About load range
Some people believe that tires with a higher load range can carry more load at the same inflation than a tire with a lower “load range”. This is simply not correct. You would be hard-pressed to measure the load capability difference between a load range D and E tire, or between G and H load range tires at the same inflation pressure.
If you are not sure, the “Load Range” is marked on the sidewall of your tires. If you don’t see the words “Load Range” look for “LR” followed by a letter usually between C and G. “Load Range” may not be in large letters but you should be able to find this information on your tires. There is more information on sidewall stamping HERE.
How much air you need in your tires
The simple answer to how much air you need in your tires is on your data sheet aka Certification Label. Depending on the year your RV was made, this information is on a sticker on the outside driver side of your trailer, or near the driver’s left elbow and visible from the driver’s seat if there is no door, or on the inside (door jamb) of your motorhome entry door.
Wherever it is, you should also have the information in the stack of owner’s manuals you received when you bought the new RV. Find this data sheet and write down the information for loads, minimum inflation, tire size and load range and place this info where you can easily find it. This inflation is the minimum based on what the RV manufacturer thought you would load into your vehicle. They may have guessed correctly or you may have gone way over that estimate, depending on how much “stuff” you carry.
Weigh your RV at least once
Every RV owner should get their RV on a truck scale at least once to confirm its actual weight. If your scale reading is near the GAWR (gross axle weight rating), then it is important that you do a detailed weight measurement.
Our next post will cover how to know the real load on your tires and what you need to do to be sure you are not overloading your tires, wheels, axle or RV.
Roger Marble
MORE POSTS ON TIRE INFLATION
- “Cold inflation pressure”: A clarification of tire terms
- More information on tire cold inflation pressure
- How to set tire pressure when there are wide swings in temperature
- Learn the basics of setting tire pressure and testing TPMS
- My RV tire pressure is showing a significant increase. Is this OK?
- Is the tire pressure too high?
- Should you adjust tire pressure when temps get colder?
- Do not adjust your tire pressure for ambient temperature
*****
If you have tire questions, check out Roger’s posts on RVtravel.com. There are hundreds of posts covering everything to do with tires.
If you still have a question for Roger after searching the above posts, send your inquiries to him using the form below.
RVT1260
Tire pressure… always a hot topic. Been RVing for nearly a decade now. Our Endurance tires are rated to 80 PSI max. I run them at 79 PSI every time. Super Duty tires are run at max per the doorjamb sticker… 75 rear, 60 front. Never had an issue. Ever. I do know of family members and friends that continue to have blowouts because they run 10 PSI below max. I check the pressure every morning before movement. We have a TPMS system installed and it works. To each his own, I suppose, but I have found that running right up to max gives me peace of mind.
Just to clarify, the “MAX” on the tire sidewall is the PSI that will deliver the highest load capacity. Not the highest psi a tire can tolerate. THIS post should help clarify the concept. But glad to see that you are keeping an eye on your inflation.