Adding cranks to a road front or rear hub?

Hello everyone, I’m somewhat in a quandary and I figured who else to ask but my fellow cyclists.

I’m taking a welding class, and I’ve built a chassis for a big wheel. I had planned on using a 650c front or rear wheel along with the carbon fork, but I’m unfamiliar with somehow adding cranks to a rim like on a unicycle wheel. I’d rather not buy a uni just to take it apart.

Any useful advise using my wheel idea? It doesn’t have to look pretty, it just has to work like a uni hub/crank combo. I do appreciate the help, and constructive advise.


Am I correct in assuming you want to make a miniature penny farthing style bike, a little big wheel if you will?

The problem with using a bike hub is where the bearings are located. The hub body rotates around an axle on a bike but you need the hub to be fixed to a spindle which is then attached to your cranks.

If you want to use all bike parts you could weld some flanges onto a BB spindle. There are innumerable things that could work but if you have to buy parts anyway I would just spend $30 on a square taper hub from UDC.

EDIT: sorry sometimes I assume people on here know unicycle jargon. UDC = (

I built a wheel like that out of a 700c deep-v rim,

are you building a bicycle or a unicycle, because you said you are in a welding class but using carbon forks, bicycle forks have a rake, uni frames are straight, you can just locate a used uni to cannibalize for 50 bucks, some cheaper ones are 50-100 dollars anyway. would be way cheaper to just do that than to buy and pay shipping, all you need is a wheel with no offset like on a single speed or front wheel that has the same size flange on the hub as the uni hub, assuming you know how to spoke a wheel.

If you decide to use unicycle equipment you will need to purchase bearing caps that weld on to a fork that are compatible with unicycle hubs. I think you’d need two sets. You can purchase them here. Unfortunately a carbon fork does not weld very well. :stuck_out_tongue: You might be able to form your own bearing clamps though if you use carbon fiber. But honestly if you are going to use unicycle parts you probably will have to use a steel fork.

Then you’ll need to buy a hub, I would recommend the chromoly ones that can be purchased here. They are available in both 36 and 48 hole.

Once you have a hub you are ready to build up your wheel using the rim and spokes of your choice.

If you go with the chromoly hub your wheel would be compatible with standard square taper cranks and you’d be ready to go with only $38 (plus shipping and hardware) spent. You could also go the more expensive route and use an ISIS hub and better caps instead of square taper but that’s far more expensive and probably overkill. Another possibility you could consider is buying the drift trike hub manufactured by nimbus unicycles. It uses square taper and freewheels but costs over $100. (Standard unicycle hubs do not freewheel.)