Alberta bound on the Vegematic

[nxski]

My hitch from E&H is rated for 5000lb tow weight. That said, if the trailer is balanced there is very little vertical weight. That whole set-up looks like a physics lesson in torque. Glad to hear the drama is over for you...hopefully.

[Rattlenbang]

My hitch from E&H is rated for 5000lb tow weight. That said, if the trailer is balanced there is very little vertical weight. That whole set-up looks like a physics lesson in torque. Glad to hear the drama is over for you...hopefully.

As far as physics goes, weight is only one of the forces acting on the hitch. Remember that there is still mass and when you hut a bump, the trailer (or any other load) can start pitching, and since inertia is a function of mass, the downward load can be far higher than simply the weight. This style of hitch is supposed to be rated at 500 lbs, although I assume that's static weight. Who knows what they can handle in terms of dynamic loads? Making it more complicated is the load in a rig like this is more rotational than a trailer tongue would be. The manufacturer guarantees it will carry 500 lbs because that's what the hitch receiver is supposed to carry. Throw in a custom hitch and everything goes out the window, though.

I've burned through three cubbies so far, so thankfully the load is dropping.

[Yokohama]

There's really no space for a couple hundred litres in the van. It's this, on top, or pull a trailer. This option provides the least wind resistance and no trailer drag. But in the future I'll put the cubbies in a couple of big plastic totes from crappy tire or something. One of the jugs (the one I burned a hole through) dripped a bit on the ferry deck and they weren't happy at all. I came down to the car deck and they had a bunch of pads under it, and a boom around the thing.

It would be possible to get a large fuel cell or maybe a large plastic drum and mount it on the platform in place of the jugs. Then you can equip it with a pump and quick connect coupling to pump it into the main tank when you stop to use your "veg station".

Of course, one could also make some kind of better supported platform just for this use.

[Rattlenbang]

Unfortunately, My tank has an air leak, or I'd just connect the vent tub to the jugs. As the level in the tank dropped it would draw in more veg. Self feeding and no pumping required! A couple of rectangular totes as fuel tanks would work well back there.

[nxski]

My hitch from E&H is rated for 5000lb tow weight. That said, if the trailer is balanced there is very little vertical weight. That whole set-up looks like a physics lesson in torque. Glad to hear the drama is over for you...hopefully.

As far as physics goes, weight is only one of the forces acting on the hitch. Remember that there is still mass and when you hut a bump, the trailer (or any other load) can start pitching, and since inertia is a function of mass, the downward load can be far higher than simply the weight. This style of hitch is supposed to be rated at 500 lbs, although I assume that's static weight. Who knows what they can handle in terms of dynamic loads? Making it more complicated is the load in a rig like this is more rotational than a trailer tongue would be. The manufacturer guarantees it will carry 500 lbs because that's what the hitch receiver is supposed to carry. Throw in a custom hitch and everything goes out the window, though.

I've burned through three cubbies so far, so thankfully the load is dropping.

Is that meaning you can hang 500lbs off it? Sticking out how far? Mine is rated to pull 5000lbs which takes into account the motions of the trailer. Even with 2000lbs in the trailer, I can still lift the tongue by hand, so I don't think the strain on the hitch even when going over a bump is too bad.

[bbisset]

...Making it more complicated is the load in a rig like this is more rotational than a trailer tongue would be...

Yes. You have to divide the length of the lever's effort arm by the length of its resistance arm. So the "resistance arm" in this case might be a weld 2cm away from the pivot/rotational point (your fulcrum). Assuming your "lever" is one meter (for ease of math), that's 50 times whatever the force is. Assuming 100kg of vegemite fluid hanging on that, there's 5000kg of force applied to that weld - potentially well beyond the 5000 lbs. rating... rotational momentum inertia notwithstanding. In a traditional trailer ball setup, the ball (where the downward force is applied) is only 20cm away from the pivot/rotational point, and most trailer tongue weights are light enough that you can pick them up (say 50kg max). So given the same criteria, that's only 500kg of force applied to the same weld.

[Rattlenbang]

...Making it more complicated is the load in a rig like this is more rotational than a trailer tongue would be...

Yes. You have to divide the length of the lever's effort arm by the length of its resistance arm. So the "resistance arm" in this case might be a weld 2cm away from the pivot/rotational point (your fulcrum). Assuming your "lever" is one meter (for ease of math), that's 50 times whatever the force is. Assuming 100kg of vegemite fluid hanging on that, there's 5000kg of force applied to that weld - potentially well beyond the 5000 lbs. rating... rotational momentum inertia notwithstanding. In a traditional trailer ball setup, the ball (where the downward force is applied) is only 20cm away from the pivot/rotational point, and most trailer tongue weights are light enough that you can pick them up (say 50kg max). So given the same criteria, that's only 500kg of force applied to the same weld.

While the math is correct, it's far simpler than the actual situation, where the load is spread out over a large area and the fulcrum is as well, as the receiver is welded along it's length. And while a hitch is rated for pulling loads and downward force loads, what's its rating for torque? All I can say is that the thing is supposed to be able to hold 500 lbs and if they were tearing out hitches, I think a few lawsuits would put them (and princess auto) out of business. My hitch came apart because it wasn't engineered like an off the shelf hitch is (one assumes they are engineered), which raises further questions of liability when you leave such a thing on a vehicle when you sell it. Personally, I would take it off rather than passing it onto another owner.

Having said that, we've traveled 800km so far with it like that. The additional straps helped carry the load without a problem.

[Rattlenbang]

We made it! 1800km of backroad, mountains, and winding BC highway on 170 litres of veg. I'm surprised how little huge climbs effect fuel consumption. We took Grey Pass from Kootenay Lake to Cranbrook, 5600 feet of climb in 16 km of goat trail, and still made 24.5 mpg. Go figger.