Tongue weight

Converting Cargo Trailers into TTTs

Re: Tongue weight

Postby QueticoBill » Sun May 28, 2017 11:08 am

Just for my clarification, the 40%/60% behind and in front of axle rule - which seems to have proponents pushing closer to 30-70 - is weight aft and fore of axle, not overall length, correct? And from 8-15% of the weight on the hitch? I'm guessing that if you just used the combined length of cabin + tongue box if any, and the axle was around the rear third point, it would be fine. Or does moving the axle back 6" really make a difference? Will I ever know whichever way I do it? I'm leaning towards being less likely to regret not moving it. I just found the spreadsheet to be too many guesses, like where do I keep a jerry can of water and will I use my cast iron or lighter weight cook gear? 1 pound cylinders, 25 pound, or white gas (which is likely for me.) Foam mattress or my regular sleeping pads? I hope Redneck is right.
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A tear with no name: viewtopic.php?f=50&t=67624
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Re: Tongue weight

Postby Redneck Packrat » Sun May 28, 2017 11:36 am

Best way to do it is, after you build it, pile your heavy stuff in it without building cabinets/mounts etc. (It doesn't matter if it's on the floor or up on the wall for this.) Distribute it where you *think* you're gonna want it (batteries in back, water in front, or whatever) and go down and weigh it and move it around until you get to get roughly 65/35 front to back. If you don't want to fill your water tanks, just pile bricks in it to approximate that weight.

When you get home, either measure your hitch to ground on a level place or even just "eyeball" it, if it looks right to you how it's setting down in back of tow vehicle. Get a feel for how it pulls while you're on the way there and back, and especially if you had to move stuff around see if you could feel a difference on the way back. Then, as you build it out, keep track of how you stay close to where you had the hitch height.

A good source for a place to find a scale would be a cotton gin, grain elevator, fertilizer distributor. All of that stuff is traded by weight in truckload amounts. Usually if you don't want an "official" weight, they'll charge only a pittance so long as they're not terribly busy when you go. Also, some of them will leave their electronic scales "on" even when closed and visible through a window as a courtesy to the farmers who might want to check their weights. Explain what you're wanting to do and if you notice the display would be visible through a window after hours, seek permission to do your playing and adjusting on a day they're closed.

I've always found that I like loading a trailer until the hitch drops an inch or two from unhooked. I suspect you'll find that's about where you want to be :thumbsup:
Bill
Texas Gulf coast, near Corpus

Working on this, started 5/2017: http://www.tnttt.com/viewtopic.php?t=68614

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Re: Tongue weight (getting close via calculated weights!)

Postby working on it » Sun May 28, 2017 11:54 am

flboy wrote:No doubt, some of the work was flying by the seat of my pants, but with a good working understanding of the need for load balance and distribution.
  • I used the trailer balance worksheet, all along, with a long-term plan in mind, to correct any/all errors I would make during the build. And, working on a low (no)- budget, for most of the build, I made many design and materials compromises that I became aware of, that further altered the weight balance negatively, to be overcome later.
  • While the goal of most American trailer builders is to achieve a 10-15% tongue-to-total weight balance, the European model strives for 7-10% tongue-to-total, since most of their tow vehicles have been traditionally lighter in weight (and towing capabilities) than the traditional, larger, American cars, and of course, our pickup trucks. I knew I was building a heavier-than-most trailer, originally to be towed by a very small vehicle, a Chevy HHR Panel, so I was trying to keep the tongue weight lighter, to go with the European model. I was encouraged by this quote, from a respected forum member, while being discouraged by others.
  • Grant Whipp wrote:“In general terms, the rule of thumb on a typical teardrop is one third (1/3) of the body length from the rear edge of the body is where the axle/spindle centerline should be. So, in general terms a typical 4'x8' bodied teardrop should have its axle/spindle centerline 32" from the rear of the body and a 5'x10' teardrop will have it at 40" from the rear of the body. However, amount of cabinetry (and where it is placed) and number of appliances will affect that figure. My 8'ers run at about 31" and 10'ers at about 43", but I don't hold cotton to that 10-15% tongue-weight spec ... I like it in the 5-7% range ... and that's just me”. – Mon Feb 12, 2007 12:36 pm
  • When I was nearing the (initial) completion of my build, I had achieved a near zero tongue weight, prior to shifting some items forward, and used test weights to measure actual balance shifts, in addition to calculated changes. Still, when I first weighed the completed TTT, without any of the added cargo I had planned for, from the start, I only had 45 lbs tongue weight, out of 1280 lbs total, or 3.52%. I tried it out that way, on the weighing trip, to also test a worst-case scenario for towing, just to see how it would handle, if I needed to tow it that way. It handled well, over twisting roads and over bumps, though I never exceeded 50 mph. But, I found out that, with just a little more weight (170 lbs, added as cargo, forward of the axle), to reach my projected "trip" loading, 1450 lbs, I achieved 9.8% tongue weight...more than enough for European standards, over Grant's stated range, and right at the standard lower limit for the American model. I knew I could get-by safely towing like that, especially since I would always have the Weight Distributing hitch system on my truck, to equalize the load, since I now had confirmed that my truck, not the HHR, would be my TV.
  • At that time, I was using a small toolbox on the tongue, having not yet found the size or style tongue box, to install on the trailer, and planned for in my initial design drawings. A forum member PM'd me that he found the ideal box for me, on Ebay, and I bought and installed it, soon thereafter. Once installed, I had the combination/variety storage spaces I had wished for, and soon, my balance problems? were solved. Eventually, as camping needs caused me to add/modify/change things, my trailer became heavier, tongue weight continued to increase, and now, is well beyond 10%, probably closer to 15%, as I just added 300+ lbs overhead weight, between the tongue box and trailer doors. I haven't re-calculated nor re-weighed the trailer, but the trailer has to be over 2k lbs now, with tongue weight approaching 300. But, without the use of a worksheet, during the build, or my constant awareness of the weights involved, I probably would've had problems on my first outings, with an imbalanced trailer. I've had none, thankfully, due to that awareness.
2013 HHRv "squareback/squaredrop", rugged, 4x8 TTT, 2225 lbs
  • *3500 lb Dexter EZ-Lube braked axle, 3000 lb.springs, active-progressive bumpstop suspension
  • *27 x 8.5-14LT AT tires (x 3) *Weight Distribution system for single-beam tongue
  • *100% LED's & GFCI outlets, 3x fans, AM/FM/CD/Aux. *A/C & heat, Optima AGM, inverter & charger(s)
  • *extended-run, on-board, 2500w generator *Coleman dual-fuel stove & lantern, Ikea grill, vintage skillet
  • *zinc/stainless front & side racks *98"L x 6" diameter rod & reel carrier tube on roof
173193172890148599
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Re: Tongue weight

Postby dancam » Sun May 28, 2017 5:35 pm

With a trailer that large its a lot easier to balance things out and the tandem axles help a lot. Not sure if its an issue with that big of a trailer but with smaller ones you want to be careful to avoid building a see-saw. Even if you get 10-15% tongue weight like you should but all your heavy stuff is at the very front and very back your trailer will bounce around like a see-saw if you hit a large bump and can bounce the back end of your tv around. Especially bad if that happens while going around a corner.
So try and plan for the heaviest things to be as close as possible to the axles.

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Re: Tongue weight CALCULATING FOR BALLPARK ACCURACY

Postby working on it » Sun Jun 04, 2017 2:30 pm

working on it wrote:I used a trailer balance worksheet, that was on this forum's design pages. I altered the format for more detailed item-by-item installation, accounting for small changes in position and/or weight. Since I started my TTT build with the heaviest items all behind the axle, I always relied on the worksheet to help me keep the rearward weight bias under control, until I could get everything I needed to put the trailer in balance, which I eventually did. I originally started camping with the nose too light (about 7-10% tongue weight), before I modified to bring it around to conventional norms (10-15% tongue weight). I'm still adding more to the front, since I have a heavy-duty truck to tow with, and a weight-distributing hitch (I always tow everything using one) for stability. My 4x8 TTT has crept over 2000 lbs now, with a tongue weight over 220 lbs, but it's been a long struggle to get there, and the worksheet kept me apprised of where I stood in that process.
  • I had been wondering about the accuracy of my post, quoted above, since I actually had not weighed the trailer in years, and not modified my worksheet in three years. I had noted the weight of items I had moved, changed placement of, or added, all along, but just kept a mental picture of what was happening, overall.
  • I located what I judged to be the most accurate worksheet, from 7-26-2014, and modified it to reflect the changes I made to my TTT since then. All my worksheets were based upon travelling loads, since that is most realistic, and useful, to judge the road-worthiness of a trailer. From the start of my build, I never stopped trying to balance the trailer, though my inclusion of everything I could possibly need on a trip, was packed (overpacked) inside the 4x8 trailer. The 1000 lb goal of my trailer build was doubled, but the strength of the trailer was of foremost concern, so I am still pleased with the way it turned out. No more additions to come. ???
  • my 4x8 trailer's travel weight has changed significantly.png
    my 4x8 trailer's travel weight has changed significantly.png (26.76 KiB) Viewed 1117 times
    my guesstimations were pretty close to calculated figures
  • I figured the loads as I will pack up for my next trip, with the canopies and pantry strapped in place on rack and tonguebox. The foodstuffs in the trailer pantry, the water aboard, and the cube-in-cube rear "perishable storage" cooler will all be loaded at the last minute, to ensure freshness, since my garage stays over 100 degrees all summer long, and I don't want spoilage.
  • PREPPED & READY.png
    PREPPED & READY.png (374.36 KiB) Viewed 1117 times
    the new travel configuration gives better balance to a once rear-heavy trailer
2013 HHRv "squareback/squaredrop", rugged, 4x8 TTT, 2225 lbs
  • *3500 lb Dexter EZ-Lube braked axle, 3000 lb.springs, active-progressive bumpstop suspension
  • *27 x 8.5-14LT AT tires (x 3) *Weight Distribution system for single-beam tongue
  • *100% LED's & GFCI outlets, 3x fans, AM/FM/CD/Aux. *A/C & heat, Optima AGM, inverter & charger(s)
  • *extended-run, on-board, 2500w generator *Coleman dual-fuel stove & lantern, Ikea grill, vintage skillet
  • *zinc/stainless front & side racks *98"L x 6" diameter rod & reel carrier tube on roof
173193172890148599
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