For all of you who care, wich you proly dont, here is a frame design i came up with 2 or 3 days ago, it consists of a neck, 2 sheets of .035 4130 and bearing holders, the addvantage is very light, and extreamly rigid, the down side is no flat crown for 1 or no footed skils. I hope to build a proto type of it soon, out friend has a sheet metal brake, a metal bender and a F’ing huge band saw, wich are the only tools i dont have that i need to build it.
heres some pics(the green is just to give a better look at how its built, without shadows it looks like a wilder frame.)
It looks like you should give that design a go. Some suggestions would be to make some more reinforcement where the seat tube meets the arch, and use thicker metal 9than what you would normally use0 at first, then if you think its too strong, you can always make a lighter one if you want. Also, it would be a good idea to put some small dia. bendable tube (that you can buy at pet stores for fish tanks)alond the outer edge od the brace, because I could see some painfull cuts and injuries from that sharp edge.
It sure looks light, but I wonder about rigidity for two reasons:
First, tubes are generally the preferred shape for lightweight, rigid
frames. Why aren’t bicycles made using this shape if it is an
improvement? Second, I don’t see how your design resists twisting.
If you crank on the handle, twisting the seatpost, what stops the
frame’s legs from twisting?
My advice is build it with thick enough metal to withstand the
stresses. Also, follow the advice of others and do something about
the exposed egdes.
Looks to me like it would weigh about the same amount as the tubing equivalent. I can picture the amount of flat sheet metal you’ve got there being bent into about the same size tubing on most unicycle frames. Looks very different to standard uni frames though.
The twisty part is the fork legs. I can’t imagine flat stock being as rigid as tubing of the equivalent weight no matter how you arrange the pieces. The current design, with only the one small rib down the side, looks extremely flexy.
It would probably take several tries to get something with good rigidity at a reasonable weight. And that means making them of course. You cant test designs in a 3D graphics program…
Tony Melton has a similar crown on his trials uni frame. I think it has flat plates instead of tubing on the horizontal bits. His frame looks incredibly cool…still remains my favourite ever trials frame.
Okay thank you, I didnt see the seat so I was about to say wow you look pretty good at the Ultimate wheel. Speaking of Ultimate wheel can anyone ride one of those efficiently enough to make it look good? I wanna see a video or something of it. And also an Impossible wheel.
