Left / Right weight

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Left / Right weight

Postby Photophobic » Thu Nov 09, 2017 3:57 am

this must have been discussed before but I can't seem to find anything...

How much concern do I need to place on left/right weight distribution? Everything i find is front/back. ideally symmetrical would be great but a cooler full of ice and beverages isn't exactly counterbalanced by the dry foods & stove on the other side of the galley. based on front/back weight I might move my battery off the tongue but won;t have a centered space for it (and a second wouldn't fit opposite).

I'm new to towing in general so maybe I'm over thinking this (i don't have a counterbalance for my weight in the truck) but rather check with experience for safety from the start while i can still make design changes.

Thank you,
Paul

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Re: Left / Right weight

Postby working on it » Thu Nov 09, 2017 10:46 am

  • I've towed a lot of trailers, some with good balance in all directions, and others wildly skewed to one side or the other, or too far front or rear, or both. Sometimes you just have to live with the bad situation, but when it's your trailer, load (or build) it with common sense, if at all possible. I have been known to load too much, and probably incautiously, but my squareback trailer build was done as well as I could, given my predeliction towards extremes (more is better!).
  • When I was building my TTT, I used the Trailer Balance worksheet in the Design Resources shortcut in the TnTTT header (at the top of this page), or here: http://tnttt.com/Design_Library/Trailer%20Balance%20101.htm. It is great to help with the front-to rear balancing, to achieve the proper tongue-to-total weight proportions, but doesn't address side-to-side balance. Normal distribution of items inside the trailer might skew the balance a bit, unless taken to extremes, it should be OK if common sense guides the placement. I'm typing this as I sit inside our 20-ft travel trailer (our temporary home for the past 6 weeks, while our new home is nearing occupancy condition), and the refrigerator, stove, water heater, microwave, propane furnace, and electrical panel are all on one side, while only a dinette and under & overhead cabinets (+ the TV and radio units) counter-balance them. Presumably, the trailer mfg. people assume the trailer owner will store enough weight inside those storage areas to compensate for their weight on one side; but if not, the suspension should be strong enough to handle the imbalance, the same as automotive suspensions can handle the imbalance of various occupants inside.
  • Since I was building a small size trailer, a 4x8, and knew I was dealing with a marginal suspension (the original axle had an unknown weight capacity, and I was expanding the 50" x 60" original frame to hold twice what it probably was intended to haul), I tried to distribute loads/components evenly from side-to-side, too. Space limitations also forced me to distribute bigger items as a counter to other large items, with small items strategically stored in the remaining space available. Two large items were designed into my plans, from the very start, that had to counter each other, in my galley area: the generator (w/extended-run fuel tank, added later...in a center-mounted position), and the A/C unit (mounted thru the rear bulkhead wall, with drip pan and exhaust ducting taking up space in the galley. The generator and slide/turn mounting weighed about 80 lbs, so the A/C and associated components, should weigh about the same, ideally. But, most of the A/C's weight is forward of the generator's, though the side to side balance effect is similar. I utilized room under the drip pan as a home for my Aquatainer water dispeser, at camp, though it weighs too much to transport in that position. Still needing some more left-rear corner balance, I at first put my battery there, then after moving it to the tonguebox, put a 5-gallon fuel jug there (I decided that that might not be the best spot, directly in front of my main 12vdc cut-off switch, and replaced it with a cooler). I filled in the remaining available spaces with Coleman gear, and 110vac surge protection and a fire extinguisher, to achieve an all-around balance, of sorts. The aquatainer rides to camp (with another, as extra water, and both serving as a tongue-weight enhancer, also compensating for the already heavy components permanently stored/installed in the galley.
  • using Aquatainer placement for balance.png
    using Aquatainer placement for balance.png (640.82 KiB) Viewed 2997 times
  • Inside the cabin, I followed the same thought process, and balanced front-to-rear, with a forward bias, and side-to-side, as best I could. Because the A/C unit was already taking up space, high on the streetside rear wall, I used an old keybox, transformed into a 12vdc inside-cabin fuse/switchbox combo. It was heavy enough to nearly compensate for the A/C weight opposite it, and again, I used smaller items to better balance the equation, inside. As mentioned before, the front cabin wall is where I strap-in my Aquatainers for travel, using an e-track, for balance. On the return trip, if both containers haven't been emptied, I put the heaviest one on the streetside, diagonally opposed to the heavy generator in the right-most rear corner.
  • balaced load on rear interior wall.png
    balaced load on rear interior wall.png (651.71 KiB) Viewed 2997 times
  • Moving forward, the tonguebox is as evenly balanced as I could make it, with equipment and heavy hardware stored inside,
    as well as the battery. Mounted on a sliding plate on the single-beam tongue, I used outrigger stabilizer struts, and a roller-on-runner support system underneath, to guarantee no weight shifting on the road. The spare tire and wheel are mounted directly behind it, in a neutral balance spot.
    aluminum tonguebox balanced too.png
    aluminum tonguebox balanced too.png (552.55 KiB) Viewed 2997 times
  • As I built it, my trailer became heavier than I originally wished, and with some heavy items mounted high up; I became concerned that the center of gravity might be a bit too high, especially if I ever intended to take the trailer down unpaved roads, or tilted roadbed. I calculated the balance fore and aft, so I also calculated it top to bottom, and strove to ensure that my center-of-gravity stayed as low and forward as possible, and that future modifications didn't adversely affect either. I modified my frame/suspension to strengthen it, and it helped the COG also. Recent additions of a fuel tank in the rear (for the genny), an overhead lift bar in the cabin (also serves as a roof joist), and the front rack over the tonguebox all raised the COG a bit, but not much. Even so, I use a weight-distributing hitch to pull my trailer(s), which always helps in any balance situation, IMHO.
Last edited by working on it on Thu Nov 09, 2017 8:33 pm, edited 1 time in total.
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
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Re: Left / Right weight

Postby Socal Tom » Thu Nov 09, 2017 11:25 am

Assuming your springs are properly rated for the rig, I'd say as long as you are less than 200lbs different side to side it probably won't matter ( that's about the weight of one person). You may be ok higher than that, but I wouldn't worry about a less than that. Everytime you drive on a road that isn't flat, your weight shifts toward the downhill side, so its not an abnormal situation to be out of balance to some degree. If you are concerned measure the distance from the frame to the ground with the trailer on level ground, if its tilted more than an inch then you might want to look at rebalancing, or getting some heavier springs.
Tom

( Full disclosure the 1 inch number is just a gut feeling, not based on any data)
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Re: Left / Right weight

Postby Photophobic » Sat Nov 11, 2017 5:56 pm

Thank you both, you've put my mind at ease a bit. My battery placement will still wait to see what my tongue weight is at but if it gets moved to the back I'll move the cooler opposite while driving, everything else should be balanced close enough.
Paul

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