projectfatbastard

This is the first of my unicycle projects. I built it using a Trek 24" BMX style fork. The hub was a hand made adaption which I discovered wasnt quite strong enough. I recommend that you dont bother trying to make your own hub, unless youre on a REALLY tight budget and you dont intend to do any bigger jumps than a bunny-hop.

I calculated exactly how much I spent on it and discovered that it cost more to build than it would cost to buy one! I stopped counting the cost after I bought the fork because I liked the idea of riding a machine I built myself. If only it lasted a little longer! took a bit of massaging to get the Nokian Gazzaloddi into the frame without hitting, but it was worth it. Without doubt it is the best off-road tyre for a unicycle you can get.

When I go into build mode, I call myself "Overkill Engineering" and this certainly lived up to it. I will weigh it as soon as I get some scales, but it is almost twice the weight of my standard United 20" with a steel wheel and cranks.

How to build your own unicycle.

I began by buying the longest BMX axle I could find, and ground off the bearing lands to make a perfectly smooth and round 1/2" OD rod with cotterless fittings on the end. I then cut it in half and lengthened the whole shebang with a bit of steel tube that I welded to it. The length is decided by where your bearings must sit (width of frame) and clearance for your cranks. Try to keep it as narrow as you can to make it easier to ride.

I tried to find a 24" wheel that was completely shagged so that I could use the hub out of it, but after a fruitless few weeks searching and going into every bike shop I went past, I gave up and bought one. I wound up with a brand new 36 hole Aluminium Rim with a steel hub attached. Note: you MUST find a hub with a larger than usual diameter, because you have to be able to somehow fit your axle through it!

You have to grind out the bearing cups in the wheel to fit your new axle through, and I found out that they are hard as nails. Stuffed 3 drill bits and it didnt even make a dent! Not being able to use a drill bit makes it very hard to make the hole perfectly round! In the end I used a high-speed grinder (or a die grinder) and a tungsten rotary burr to round it out. If you turn the wheel every other time you run the burr round, it winds up pretty even and round. Once its big enough to fit the axle in, weld it into the wheel so that it cant move. Thats about it for the wheel/hub assembly.

Get your hands on a 24" Trek chrome BMX fork. grind the weld off the bottom of the headtube and bash the headtube out. Unfortuately, the headtube in that fork is tapered on the inside so its gotta go if you want to fit a seatpost. Find a suitable sized replacement tube (1 1/8" OD x .058") and bash it into where the headtube was. Weld it in and clean up the dags on the inside of the tube so you can slide the seatpost through.

This part is optional. I did it because I couldnt find those united main-cap bearing caps that are on most uni's, so I made do with pressed steel pillow blocks. This setup is much heavier, due to bigger bearings and the extra 3/16 steel plate you have to weld to the ends of the frame so that the pillow blocks dont bend. Use end caps if you can get them.

I made my seat post from a bit of 4130 chromoly I had lying around that just happened to fit in the hole. I drilled out a flat piece of 3/16" 4130 sheet to look like a seat mount and bent it in a vice. bit of welding and that was that.

Bash it all together, and there you have it, your very own unicycle!