Estimating your teardrop weight

[angib]

Sharon Heisley has done a magnificent job in cataloguing over a hundred teardrop weights and this has given the opportunity to reverse the process and say what does a typical teardrop weigh?

The data is shown in the graph below, for those that read graphs - weight up the vertical scale and plan area (body length times body width, both in feet) on the horizontal axis. The red squares are foamies, I believe, which shows they can be the lightest trailers. The biggest thing to notice is the huge range of weights at each size. This gives the most important conclusion - the weight of a trailer depends a lot on how heavily it is built. That sounds obvious, but it is important to recognise that when someone asks "how much does a 4x8 Benroy weigh?", there is not a single right answer, just a huge range of right answers.

Sharon trailer weight graph.JPG (59.27 KiB) Viewed 34478 times

Excel worked out the black average line thorough the middle and I've added the red 'Heavy' and green 'Light' lines by eye. These can be turned round into simple formulas for estimating trailer weight, as follows:

Light - Trailer weight (pounds) = 15 x Body Length (feet) x Body Width (feet)

Average - Trailer weight (pounds) = 25 x Body Length (feet) x Body Width (feet)

Heavy - Trailer weight (pounds) = 40 x Body Length (feet) x Body Width (feet)

And, yes, that means the heavy trailers are nearly three times the weight of the light trailers for any given size! That's why there isn't any one 'right' answer to what will/should my trailer weigh? You need to calibrate your own behaviour first. If you design aircraft structures for a living, you can probably build at the 'light' weight. If you don't believe plywood is made in any thickness but 3/4", you will probably build at the 'heavy' weight

[citylights]

Excellent! Love to see statistics in use.

The variability of teardrop weight is not entirely dependent on the construction. It is greatly dependent on options too. An air conditioner, mini-fridge, built in stove, 15-inch tires, and battery will take a light weight teardrop right up to the heavyweight line. The difference is only a couple hundred pounds.

I am glad to see... Mine is not above the red line!

[48Rob]

Andrew,

Thanks for your continuing contributions!

Rob

[eggsalad]

I'll call the formula "good by me". My TTT is most definitely not a teardrop. It's a 4'x7' box for sleeping only.

By this math, it should weigh about 420lbs. Because I used an old PWC trailer, my weight is a bit higher, at 470lbs. I'll call that fair.

[working on it]

If the weight of "heavy" trailers are usually near the median described by this formula Heavy - Trailer weight (pounds) = 40 x Body Length (feet) x Body Width (feet)
then my build is in its own category, the Neutron Star-Class-Trailer weight (pounds) = 55.5 x Body Length (feet) x Body Width (feet). Not only did I use 3/4" plywood in my build,

If you don't believe plywood is made in any thickness but 3/4", you will probably build at the 'heavy' weight

but incorporated neutronium wherever I could, to ensure that it would grip the road. EDIT 10-26-14:Weight reduction program still in progress. Now weighing in at only 1518 lbs, just 47.44 x body length x body width.

sky's%20the%20limit%20for%20weight!.jpg (45.9 KiB) Viewed 33206 times

[Sparksalot]

Very cool graph. My own Compass Rose falls between the medium and heavy lines, only because I could not find a source of 1/2" oak veneer 4x10 plywood.

BTW, 5x10 coming in around 1400#. Any heavier and I'd want to have brakes because I can feel her pushing at times.

[doug hodder]

Andrew,

Thanks for your continuing contributions!

Rob

Amen...I've working on my 7th build and have called on Andrew a number of times. His expertise has always given me a feeling of confidence in my frame builds. I can weld, but am by no means an engineer. I've really learned a lot from this gentleman. I come in light and strong which is what I'm shooting for. Thanks Andrew!

And a big thank you to Sharon for putting this chart together! It's a great resource for other builders. Doug

[mikeschn]

Now it's sticky! Thanks Sharon!

Mike...

[pcs]

Starting a first build. Dose this formula include the initial trailer weight, or should I add it?

[Sparksalot]

Starting a first build. Dose this formula include the initial trailer weight, or should I add it?

My tear is one of the data points. I included the frame in the total.

[S. Heisley]

.
The weights are for completed (or at least camp-able) trailers, including the chassis (metal frame, wheels, etc.).
It is said that home builds are rarely truly completed because builders are always finding ways to improve them.

Please recognize that the weights are not a formula but rather the highs, lows, and average weights volunteered by our forum members.
What your teardrop will weigh is mostly dependent upon you and how you build yours and, yes, that includes the weight of your chassis as well as your cabin.

[noseoil]

Figured I should post this here, since I'm starting and have no idea what it will weigh based on real-world experience with trailers. I set up a spreadsheet on the "rolling weight" estimate, and it comes in at a hefty 1322# including the frame & all the stuff inside. How close is this really? I don't know at this point but it's based on a summation of parts, materials and "stuff" which will be used in the build. I'll edit this post once I'm done and can get it weighed on a certified scale.

The frame is heavier than I would have built myself, but it was a "good deal" & too good to pass up, since it was a commercially made flat top which was about the right size already. It's actually a little too well made, since it tips the scales at a hefty 510#, a bare rolling weight for the frame & tongue box after stripping as much off as I could. My projected weight comes out at 29.33 pounds per square foot (5x9 Benroy) and the cost will be about $110 per square foot (materials only, no real labor other than a little welding by a friend in his shop). Let's see how I do with my figuring. I'm tracking hours but have no idea what it will take to finish, so no estimate on that part yet.

Perhaps another chart on cost per square foot & hours per square foot in the future might be in order? Thanks for posting this chart, it's a great idea. Here's the obligatory "before" shot.



The "after" shot will be ready in the next year or two..... Best, tim

[drhill]

510 lbs for that trailer with the tongue box isn't too bad at all. I built a 5' x 10' flat deck with plywood deck and a long tongue (about 65") to accommodate a bike rack. The trailer has ST205/75R14 trailer tires, 3500 lb axel and 2500 lb springs (1250 per side). The trailer weighs 585 lbs complete with spare tire, but excluding the tongue box or teardrop pod. I want the trailer to be heavy enough to haul a good load of firewood, lumber, furniture or whatever. I weighed it once at a weigh scale at 1960 lbs and that was with the teardrop pod, bike rack and 4 bikes, two coolers, 10 gal water, 2 propane tanks, folding canopy, folding table, tent for other people --- fully loaded for a 4 day weekend. I am real curious to go weigh it with the tongue box and pod but no other gear, but that is about 50 km each way. Maybe in the spring.
enjoy your building.

[Dalorin]

I know that this is an old thread, however, I'm wondering if anyone knows how much weight you save if you do not skin in aluminum.

My trailer alone tips the scales at 550 lbs. I wanted 14" wheels and that meant the manufacturer used a larger axle etc. I decided not to skin in aluminum for many reasons but I imagine that I saved myself some weight as well.

I'm trying to keep the total weight under 1500 because that's the max for my 4 cylinder RAV4.

[S. Heisley]

I know that this is an old thread, however, I'm wondering if anyone knows how much weight you save if you do not skin in aluminum.

My trailer alone tips the scales at 550 lbs. I wanted 14" wheels and that meant the manufacturer used a larger axle etc. I decided not to skin in aluminum for many reasons but I imagine that I saved myself some weight as well.

I'm trying to keep the total weight under 1500 because that's the max for my 4 cylinder RAV4.

I believe that this would, again, depend upon the builder. That is because one must consider the type of paint, whether there is epoxy and/or primer put on before the paint or aluminum; the number of coats of paint; and, possibly even the thickness of the aluminium sheeting. So, it might be hard to say.

If you look at the cans of paint, they will sometimes tell you how much the paint will weigh, once applied and dried, and you could probably calculate it out for both the paint or the aluminum that you are considering and at least come close.