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Ben @ TriSled made a quad for some guy in WA and I saw it before it went out. Or possibly when it came back for modifications. Either way, I wanted one.

My excuse was that I was going to be doing an unsupported group tour and wanted to be able to load up on gear without the hassle of a trailer. By the time you build a trailer that can cope with 100kg of stuff, work out how to attach it to the bike, how to stop it when you want to, and how to avoid it trashing you and the bike if you stop or turn too fast, it's just a giant PITA. So, a four wheel load bike.

I asked for it to take one of the big black bins from Bunnings, and of course I went out and bought the biggest size - 220 litres. It weighs about 8kg. But the quad actually came with one of the smaller ones so I use that as a lid, and also as the bin when I'm not carrying huge loads.

The bin acts as a really effective airbrake, and the lid helps, and a smaller bin is less of a brake. But I'm still doing well to average over 20 kilometres per hour for any distance. Once I was on tour there were a couple of times I rode it without a load in and was spinning along at 30kph going "whee", but that required touring fitness *and* a short journey.

The quad as it arrived, and I immediately fitted it with mudguards and a chain guard. The double chain idlers at the front mean the chain length doesn't change when you slide the boom in and out. There is extra drag, but it's never bothered me enough that I've bypassed them.
Note the bolt through the axle in that last photo. It's important later.

Quad in use shots. First is on tour, with 20W solar panel and the camera set up so I can take selfies.

You know that bolt? This is not that bolt. This is the bolt I bought to replace the bolt I bought to replace the bolt above when it broke. I got about 1000km to the bolt. For a month through Queensland.

This is what Ben did to the other quad when the guy wanted lower gears. It's still derailleur geared, but the second stage halves the ratio. Speedy this quad is not.

My demands were much less reasonable. Two wheel drive and a Rohloff! Much crying on the phone later Ben finally managed to get a couple of industrial freewheels rated to the sort of torque he needed. To stop me breaking them. If you do the maths it looks a bit ugly. I can press about 100kg per leg, and let's be realistic and say I don't pull much. So, 100kg at 165mm is 981N * 0.165m = 162Nm at the bottom bracket. Then we gear down using a 24T chainring and the 34T sprocket to get 230Nm at the rear axle. That's mid-range 4 cylinder car engine territory. Or, at 10mm radius where that bolt was breaking, 23kN of shear force.
Turns out that there's not a lot of demand for industrial freewheels like that, but some German company makes them. A snip at $500 and 1kg each. Oh well, give me a couple of them, then :)
And one little hiccup... I'm stressing that Rohloff to close to the torque limit. Pretty regularly. So when it came time to flip the cog I spent a long time soaking penetrating oil into the thread and faffing about. I still shattered the Rohloff cog removing tool and damaged the hub. Without getting the cog off. I think it's stuck. Luckily the hub isn't built into a wheel, so it'll be cheaper to post back to the Rohloff factory and say "fix this please". I think this is the major defect with the Rohloff hub, they should have gone with splines here.

My quad, with the matching trailer I built because it turns out that 120kg of stuff is not enough. And one of Ben's pretty quads so you don't all think he only makes agricultural machinery for the likes of me. These days he's doing three wheelers for loads because that's where the money is, but I'm sure he could be bribed to make another quad.

And my tow bar, since that's something Ben will not fit. He said "don't be an idiot" or something.
So I sent him photos of my four wheel trailer.