I am in the process of build a freewheel uni so that I can coast with my feet still on te pedels. I am aware that I will not be able to ride backwards or hop and that I will need to install a hand brake. I have my design figured out for the most part all I need really is a set of spoke rings. Anyway I would appriciate any help you guys could offer especially in building a hub from scratch.
If you have a powerful enough brake on it you will still be able to hop the only problem will be that you will have to hold the brake on while grabbing the seat. But that wouldn’t be that hard. I’d like to know your planned design for the hub and crank set up.
I think what ever you do a free wheel on a unicycle would take a bit of getting use to.
As soon as I start assembling the hub (still have some problems) I will keep you up to date.
That sounds great! I love all these new inventions. Keep us posted please.
the easiest way that I can think of to build a freewheel uni would be to custom-build a short chain-driven frame, then use a rear bicycle wheel, chain rings and all, because rear bike wheels already have freewheel capabilities.
You also might want to make sure that the gearing ratio between the crank arm sprocket and the wheel sprocket is fairly easy (1:1 or lower, because I’d really hate to fall off a giraffe (albeit a short one) while freewheeling going really fast.)
I custom build wooden uni frames, you can email me if you need help.
Ken Fuchs and Tom Miller made a freewheeling unicycle once. I think all they did was use a different type of wheel bearing. This was a simple solution, using some form of one-way needle bearing. You pedaled to pick up some speed, then tried to coast as long as possible. With the addition of a good brake, you should be able to do some interesting things with it, but I think it will always be much more advanced than riding a regular unicycle.
Ken’s bearings seized up or failed after a while, though. I’m guessing they were not intended for the amount of force that was being used on them. But if you can find some one-way bearings, that would be a heck of a lot easier than having to build a custom hub.
I’ve got a half a converted coaster brake uni hub somewhere - It got shelved in favour of the full - susser.
John Foss wrote:
>Ken’s bearings seized up or failed after a while, though. I’m guessing
>they were not intended for the amount of force that was being used on
>them. But if you can find some one-way bearings, that would be a heck of
>a lot easier than having to build a custom hub.
The inside diameter of the hub shell was probably increased after months
of braking action on that surface. It probably should have been a
tighter press fit. Switching the clutch bearing to the other side
Also, it is probably true that the clutch needle bearing used was not
designed to handle the torque generated by human legs. I tried to baby
it, but the first one still eventually failed. However, the replacement
bearing never failed, probably due to my increased experience on the
cycle and the continued avoidance of over-stressing the clutch bearing.
Ken Fuchs <firstname.lastname@example.org>
Re: Re: freewheel
Power Cranks <http://www.powercranks.com/> use clutch bearings (one clutch bearing on each crank). These are weird cranks that only apply power when you pedal forward. The clutch bearings they use are able to handle the power output of professional road cyclists without slipping. The bearings were rather large which explains the somewhat bulky design of the cranks.
Perhaps you need to use larger clutch bearings. Or the hub body may need to be made out of a harder material.
With the right bearings and the right hub body this is probably the easiest way to make a freewheel unicycle hub.
The other option would be to convert the rear hub on a mountain bike. It would be more work, and would require more machining and design. But it might not be as prone to slipping under heavy load. If the hub engagement delay is an issue some of the fancy hub designs (like Crhis King <http://www.chrisking.com/hubs/hbs_index.html>) engage more quickly than lesser hubs. But wow! that would be a spendy unicycle hub.