Single Wheel DIY Trailer

So I decided to make a single wheel bike trailer, attached to both seat stays, in a slim, long design.
Plan is to use as much scrap/recycled material as possible.

Welded together some shelving to make the frame, then the horizontal pivot was made using some workshop scrap and more shelving.
The vertical pivot works with one tube inside another. The inner one is free to move, the outer one is welded in place.

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Did some tack welds for test fitting, then welded up properly and spray painted in rattlecan silver.
Built up a wooden box to sit on the frame, held in place by bolts and ply struts.
The trailer attaches to the chain stays using quick release pins. The plate itself attaches to existing points on the frame.

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To do:

test ride it properly
learn to weld...
grind down the welds so it can pivot left and right a bit more
grease the vertical pivot
redo the attachments to the bike.

I'm starting on a second trailer, and plan to do the attachment arms out of tubing, they should fit better into larger tubes on the plates (again using the QR pins)

I've not done metalwork before, and for a POC build I'm happy enough so far.

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That's a cool little project. How long did it take you in all?

I'd guess about 25 hours here and there. Had it on the bike last night and again this morning. Works really well, just a bit rattly but i can fettle those rattles away I expect.

It needs a flag on the back and some kind of stand to keep it upright when not attached

I like the concept.

Welding tips: turn the power up on your MIG and use the back of your other hand to guide the torch. That way you’ll get better weld penetration and the welds won’t be all wiggly because you’ll have better control over the torch.

thanks. i definitely need to practice. i find it hard to see. the work is usually just at the distance inbetween my long and short sightedness range so its out of focus.

Ah, that sounds a bit annoying. Have you got an auto-dimming mask? Even one of the £30 eBay cheapies will make it a lot easier if you’re using a fixed shade mask.

Yes it's auto dimming, I've just got poor focus at the distance I tend to be welding at.

Starting on version 1.2 next. Box tube, better fixing to bike. Version 2.0 will be for sale :)

Why so narrow for the body of the trailer?

I figure wider things can still be sat on it, either directly or by adding a platform. Narrow works well for tents and other longer items. I need to check it's wide enough for a 4 pack of beer. And narrow is more stable with a single wheel.

Plus I like the look, it kind of flows from the two seat stay attachments