I like to remove my camper in the winter so I can throw a snowmachine in the bed. I built a pulley system in my garage for one-man removal (basically a beefed up rip off of a Harken Hoist). I originally built this for my old fiberglass topper so the pulleys aren’t exactly where I want them, but it works pretty good!
I use the hoist to lift it off, then set it on 2x4s underneath to take the some of the stress off the aluminum extrusions (and for extra safety factor since I park my truck underneath it). Also allows me to lower it back down to open it up and dry out.
Added some spacers so I could use 1/4-20 t nuts. Lugs should be able to handle about 2000lb - I believe the t track would rip out before the lugs would fail. They also make great tie down points when throwing the canoe up on the beef bars!
Great question - if I were to do it over I would make them taller and mount them on the lower extrusion.
Honestly I was just trying to minimize the material I used. And leave the lower t-tracks available to slide around other future attachments. I didn’t think the upper extrusion would flex as much as it does - and I didn’t really think through the fact it would put stress on the hinges and locks.
First let me say - I agree that suspended loads can be super dangerous, and I do not stand underneath my GFC until I string up the 2x4s underneath for extra support. Looks like adv_riggs had a similar idea with some webbing straps.
That said… aluminum is a lot stronger than you might thing. I’ve spent a fair amount of time playing with 80/20 and have always been impressed with how strong it is. But once I saw how much the extrusion flexed under load I got a little concerned and actually ran a few calcs (I’m a mechanical engineer and a bit of a nerd…). These extrusions are custom, but pretty similar to 1x3" 80/20. Modeling it on 80/20, each extrusion should be able to hang ~750lb. T-nut tear-out for 1/4-20 should be somewhere around 500lb ea. Disclaimer, these are just some napkin calcs, so don’t take my word for it - be safe and be cautious.
Good Mechanical Engineer! I always say 1/4-20 is good for 700Ibs of camping force.This is in shear and it’s extruded so .
How are the V2 RTT attached to the lower frames on this? If I remember correctly on my V1, the RTT looks bonded to the steel tube frame. Please correct me if I’m wrong.
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