Differences between towable, motorhome and car tires

Differences between towable, motorhome and car tires

RV Tire Safety
with RV tire expert Roger Marble

This is a summary of a discussion I had on an RV Forum on tire pressure that started with a question and some comments.

Question: “I’ll give my take on maybe why we have travel trailer owners, motorhome owners that never had a TT, TT owners that moved up to a MH, MH owners that act like they still own a TT – maybe there is another I can’t think of right now. The point is, tire pressures are figured differently between the RVs’ owners involved. I have friends that own motorhomes  and suffer blowouts all the time and their tires look good at the pressure they are using and not a Run Low Flex Failure that will most likely cause a blowout. Maybe Tireman9 will answer some of the differences between tire pressures of travel trailers and motorhomes to clear up some of the misconceptions people have.”

Here is my answer to the broad question:

Yes, the proper inflation for a motorhome and a “towable” RV are different. There is actually strong science behind why there is a difference. This blog post is a short explanation. You can read the technical info here.

The other issue is that some folks just do not want to hassle with vehicle maintenance required with RV ownership. They are used to cars that have thousands of man-hours of engineering design, testing and development to make those vehicles extremely reliable.

Some of us are old enough to remember that when we learned to drive we were taught how to change a tire, as 10,000 miles was good tire life. Many probably learned how to change oil or adjust a carb. Some even knew how to set the engine timing and change a set of spark plugs. Nowadays it’s hard to even see the plugs but with their life now at 50,000+ and the ignition computer controlled and many tires good for 40 to 60k miles, who needs to know how to maintain a car?

RVs have a number of systems that do need maintenance. The tires on RVs are an outlier. While top tier tire companies use essentially the same rubber compounds and tire building equipment, this blog post explains the concept of “tiers” in the tire industry. If you have a MH you will probably recognize the brands and names of the tires on your RV. 

However, if you have a “towable,” and by this I mean both 5th wheel and more basic “travel trailers,” many of you probably have tire brands that don’t even fall into the 5th tier level. Some of these off-brand tires may not have a lot of up-to-date engineering built into them, but IMO the main problem is the selection of tire size and load/speed capacity made by the RV company.

Again IMO, many RVs are sold based on low cost but the unit has lots of “bling.” I don’t think I have ever heard of a salesman touting the benefits of the tires that come on an RV. I doubt that many even know the size or maybe even the brand provided on the various units they sell.

So the bottom line is that tires on RVs need more maintenance than the tires that come on cars, partially because of their usage but also because there is such a small margin of extra capacity provided based on the tires being undersized to keep costs down. Maybe if RV companies spent more, or even some, time evaluating better options, i.e., had better quality for the tire sizes and type they offered, the incidences of tire failure on RVs would be less frequent, just as they are less frequent on today’s cars. 

Read more from Roger Marble on his blog at RVtiresafety.net.

##RVT818

 

 

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7 thoughts on “Differences between towable, motorhome and car tires

  1. Kevin Endres

    Yeah, some problems with Towable tires and RV tires are the purchasers. I purchased a used 5ver and the owner I purchased it from had car tires on it, rated at just under 1000 lbs each, the gvwr was 10k. After checking the tires, which looked properly inflated I found the tire pressure to be 65 psi with the tire clearly stating no inflation over 32 PSI at the rated weight. He also stated that he replaced two of the tires on his last trip to Illinois from Florida and the other two were replaced on the trip down.

    No kidding. They got replaced with properly rated tires before It left my house. I wouldn’t even tow it to a dealer for replacement.

  2. Tommy Molnar

    I’ve been noticing uneven wear on my travel trailer tires from time to time. I’ve even had to have the trailer axles straightened twice, though I think this issue was caused more by bad roads and pot holes then anything else. One tire guy explained how simply turning a trailer with dual axles results in different tire wear on the front axle from the rear axle. Thinking about how the tires twist and bend in sharp turns (like backing into a campsite), it makes sense to me. And Roger’s article seems to back this up.

    I’m not sure what “technical facts” Rob desires.

  3. David Ozanne

    I recently replaced the tires on my motor home. This is the first time I have been told that the steering tires and the drive tires use different treads. I have Hercules tires 14 ply now and the tire pressure is higher than the old tires required. I suggest that anyone changing their tires on a motor home, go to a dealer that services commercial trucks and find out from them what tires to buy and what the pressure should be.

  4. Ralph

    I found this article interesting and informative.

  5. Roger Marble

    Rob, Not sure what your question is. Do you have alternate data and Finite Element analysis available on tires subjected to the cornering forces in multi-axle trailer application? If so I would be very interested in seeing your analysis.
    My direct contact email is available on my blog http://www.RVTireSafety.net

  6. Rob

    I am sorry but this article really has no value, if you’re going to write about a topic than explain your conclusions with some technical facts.

    1. Chuck Woodbury

      No value, Rob? I can’t agree with you on that. Maybe not to you if you’re an expert on the subject, but I kinda think maybe some other folks found this of significant value. Maybe they will chime in with a comment.

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