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myredracer's avatar
myredracer
Explorer II
Jun 11, 2013

What makes up a GVWR rating?

I am wondering what it is in the design of a trailer's frame and suspension or otherwise that gives it a particular GVWR rating. Is it the axles primarily?

We have a trailer with a GVWR of 6800 lbs but it weighs in at 6600 lbs without much of any significance loaded into it. We are having serious frame issues (on a new trailer!!) and need to re-inforce the frame and strengthen it due to extreme flex and movement of spring hanger brackets. This will add weight though. The weight of steel will cause the GVWR to be exceeded. We *could* replace the 3500 lb axles with 4000 lb ones. The I-beam needs strengthening and when done should be able to carry more weight. The axles do not see the full weight of the trailer since some is on the tongue (almost 1000 lbs in our case). Due to an excessive side to side movement of the spring hangers (they are tall at 6" high) they will get tied together from one side to the other and we may use the Mor/Ryde crossmembers. The bushings in the spring hangers are worn out all ready and our trailer is only 2 months old and we have only towed it about 100 miles. The frame is already showing signs of failure. There is also substantial bounce in the rear of the trailer and I think some may be due to vertical frame flex. Very poor design. FWIW, welding is not the best.

With all the remedial work needed on our frame, will it effectively raise the GVWR? Is it even possible somehow to get it re-certified with a higher rating?

53 Replies

  • Yes the GVWR is limited by many things, including the frame strength, axle weight ratings, hitch capacity, ball size, and other things to much to list.

    It seems that your frame is design critical at about 6,000 pounds, with spring hangers not rated for much more than that weight. The frame should not show stress cracks until well into 80,000 miles and 10+ years of service, even then cracks are not "Normal" but a sign that perhaps the steel is a little to thin for the weight applied to the chassis.

    So my guess from the information provided is the manufacture put a trailer to heavy on the frame that is to lightweight. Strengthening the frame might help, but in reality, a stronger frame with thicker steel walls, and more weight capacity on the axles, spring mounts, springs, brakes, hitch mount, ect. all lead to a larger weight capable trailer frame.

    So the limiting factors? I have not seen a 2" ball mount rated over 5,000 pounds capacity. Beyond that weight, they go to a 2-5/16" ball mount, rated upwards of 13,000 pounds - that I have seen for sale, I hear they go higher though.

    Axle weight rating. Say you have a 4,000 pound axle weight rating, and one axle, the GVWR might be as high as 4,500 or 4,800 pounds, with the remaining weight on the hitch, however a more conservative manufacture would place a GVWR within 350 pounds of that 4,000 pound axle weight rating. If a higher weight was required, they would be prudent to increase the number of axles, or increase the GAWR. With 2 axles, rated at say 3,500 pounds each, then a 7,000 to 7,500 GVWR can be built on that chassis, depending of course on the frame thickness, height, and construction.

    There are 13,000 pound GVWR trailers with proper frame construction, and a pair of 6,000 GAWR axles under it. The manufacture relies on the hitch weight of 1,000 pounds to balance things out.

    Anyway it seems like you need to take everything you put into the trailer out, and take it to a scale. If the trailer is significantly over the manufactures GVW empty, as advertized, and you can not safely add 800 pounds of camping stuff to it, take it back to the dealer, and let them deal with the lemon laws, and facts that you can not use it safely.

    If you start to modify the frame, then the manufacture can cancel any remaining frame warranty due to un-authorized repairs and modifications.

    Fred.

    Fred.
  • You absolutely correct, this should not be. We discovered bent spring hanger brackets (about 5/" to one side) the day after we picked it up. I had taken it to an independent RV shop to get a LP gas fitting and they noticed. I reported it to the dealer immediately and it took Lippert about 6 weeks to say it is "within spec."

    I then took it to a frame shop which is also a government certified inspection facility. When the trailer is up on the hoist, the hanger brackets bend one way, and when the trailer is on the ground, they bend the opposite way. The lower flanges of the I-beam are distorted where the hanger brackets attach. When they push on one side of the trailer, the wheels go wonky and way out of camber. The spring and equalizer bushings are worn from all the flexing. We are on the west coast so it would have been towed about 2K+ miles to the dealer.

    The frame is made from paper thin sheet metal. The beam is 3 pieces of sheet metal welded together to look like an I-beam. The metal is simply too thin. We are looking at $1,000 - $2,000 to do the remedial work. We have sent the report and photos from the frame shop to the dealer and they are waiting to hear back from Lippert. Not sure how this can be "within spec." The frame will eventuall crack and/or welds will fail unless it is fixed. Even then, it will still be substandard and the only way to fix it would be to replace the frame....

    It's pretty pathetic that they are putting this stuff on trailers and trying to get away with it.
  • This is curious?
    It is a new trailer (2013) and you should not be having "serious frame issues." Keep in mind that some of that weight will be tongue weight and thus will go to your tow vehicle..about 13%.

    You should not be having these issues unless you have really overloaded or have abused it in some way...(rough off road travel, improper jacking/stabilizing, etc.)