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Hammerboy's avatar
Hammerboy
Explorer
Dec 08, 2016

Another tire question

I've been searching the forumns but can't quite find what I am looking for as far as tires for my unit.

Our fifth wheel we purchased this past spring wieghs in just under 9k dry, has a gvwr a shade under 12k and a pin wieght of around 1500 pounds. These are published wieghts as I have not taken it to the scales yet for real world weight.

In all the years of owning a rv, I never had much concern or any trouble for that matter with the stock st tires they came with. We never took any really long trips either. Our unit has 15" aluminum rims with the dreaded Towmax tires. So my question is what tires would you put on? Would you move to 16" rims for better choices and Craigslist the old ones? Are all st tires rated for 65mph? My unit not a heavy beast like a lot of you guys pull so I'm not sure if I should go to lt tires or stick with st's.

17 Replies

  • Not all ST are 65mph rated.

    Just bought a new TT. I was surprised to see they have a speed rating of 75 mph, rated as L I beleive. Can't remember the brand but they are ST, and yes, made in China. BTW I have no plans to test the speed. Usually towing 60-65 mph.
  • donn0128 wrote:
    Sorry but one simple answer is YES, I would swap to 16 inch LT tires and enjoy the safety and longevity they will provide.


    ^^^^THIS^^^^
  • Dry weight number is of little value unless you only tow the trailer with nothing in it.
    GVWR is just a number you should not exceed but without actual scale weight there is no way to know the real tire loads.
    The reality is that over half of RVs that have been weighed discover they have one or more tires or axle in overload. This may be due to just having too much stuff in the RV or the load not being evenly distributed. Individual tires do not care if the tire on the other end of the axle is underloaded by 10% if the tire we are looking at is 5% overloaded.

    It is suggested that tire load capacity be at least 15% above the measured scale weight for every tire.

    Tires on trailers should be run at the tire sidewall inflation to lower the belt Interply ShearInterply Shear force that is trying to tear the belts apart.
  • Ivylog's avatar
    Ivylog
    Explorer III
    I use nothing but used takeoff LT tires on my many trailers. You can find a match set less than three years old mounted and balance for less than $50/tire. At 10 years of age from new I think about replacing and rarely are my trailers lightly loaded and I've been doing this for decades. By going up a size you should have plenty of carrying capacity even with a LT 15" tire.
  • Get tires and wheels rated for the full GVWR shown on the sticker.
    At that level I agree LT is a more reliable tire.
  • Sorry but one simple answer is YES, I would swap to 16 inch LT tires and enjoy the safety and longevity they will provide.

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