Freewheel Unicycling Megathread

In this paragraph, you could add bearing dimensions to fit square axle in ISIS frame. The dimensions announced by @muni_ben : here (17x42x12mm)
I didn’t check the measurements, but I just ordered 4 of them on aliexpress. :innocent:

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So I put that info in the build FAQ but perhaps it should be there also.

I’ve had similar bearings on all of my freewheel hubs for a few years now (although I ordered them from eBay) so I can say that the sizing is definitely correct.


@qu-ax, is there any chance of an update to the estimated release date for the new hub?

I know there have been delays due to COVID so I’m guessing Spring is unlikely now?

Also do you know yet whether there will also be a complete wheelset/unicycle for sale or offered as a built to order on the website? I know even back in the Nimbus Drift Trike hub days people were asking about complete wheelsets rather than having to arrange all of the wheelbuilding themselves.

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Spring is impossible, indeed.
Delays in bike-industry (to which we belong, supply-wise) explode - on some items, they are about 2 years!! now. I would love to have it until end of year, but every date I would name now would be like claiming to know when the pandemic is going to end :slight_smile: sorry.

As this is rather a specific item - and most riders will want another rim (than the one I would have in mind right now), it’ll most probably be as spare. But that is also like thinking about making a 5.000 or 10.000 people party once the pandemic is “over” :slight_smile:

Sorry, I can fully understand you impatience - and once I know more, I will be glad to share, but right now, I cannot tell more precisely, sorry!


Thanks for the update and your continued work on the progression of the niche within a niche that is freewheeling!

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Here are some pictures of my freewheel hub.

I made the hub housing a bit different to the drawing.
It was easyer to build two parts welded together with a short piece of pipe between them. Building it out of 7075 aluminium would be less weight.
The axle is built as a pipe. I cut off the isis ends of a bottom bracket and grinded them on a lathe. So i could stick them into the axle and braze it together with cusi3.
Inside the hub there are two csk25pp 2rs one-way bearings. So if they are turned arround the disc brake is on the right side. Outside there are normal 22x42x12 isis bearings.
To hold the disc there is a big washer screwed to the hub.
I think everyone who is able to use a lathe and a simple milling machine is able to diy.


How did you maintain concentricity and symmetry of the ISIS ends of your new axle?

It seems like it would be very easy to get skewed bearing surfaces as well as crank interfaces.

Looks like the inside of the axle and outside of the ISIS end could be turned/machined to a pretty close tolerance and then some relief ground on parts of the ISIS end to allow for silver brazing. Alignment should not be a problem.

Yes i made a very close tolerance between the inside of the axle and the narrowing of the ISIS. I hammered the ISIS ends into the axle. Between the ISIS and the axle there was a small V-gap for brazing.
Before brazing i put the cranks temporarily on to aline them.


I think you mean concentricicicity :stuck_out_tongue:


I umm, don’t know what you mean :wink:

It doesn’t help that my spell checker doesn’t understand the word concentricity, so concentricicity looks identically wrong when checking messages

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So, this is a thing.


Awesome! Please share a link!

First a plea. Please don’t everyone go out and try and work out how to get hold of one yet unless you’re prepared for possible disappointment.

So far nobody has tested them on a unicycle, and I’ve no idea about availability (probably poor with the pandemic situation and the other issues right now in the cycle manufacturing world).
@rogeratunicycledotcom is going to enquire.

With that out of the way, it’s the 1:1 freewheel hub of the bicymple (

Some info got posted on the Facebook group.



What about the geared hub from the penny version?

Super dangerous! Rolling at 25km plus per hour and freewheeling…

Is that a real issue? I can top at 27+ kmph on a freewheel with a good brake. A geared freewheel hub would certainly need some time to be used to it but it can be great.

Dadn’t had @waaalrus a geared freewheel (but with much higher ratio)?

There’s a 3.8 ratio on some geared hub. @toutestbon has one on a 20".

What about the geared hub from the penny version?

It uses/used a freewheeling Schlumpf hub.

As they were custom engraved with bicymple, they clearly had a production run done for them, but I had previously presumed that they were square taper hubs.
Based on these 1:1 hubs being ISIS I’m now thinking that they had a custom run made of freewheeling ISIS Schlumpf hubs, which with the BrakeFast Schlumpf Brake Adaptor would allow a 2 speed freewheeling unicycle with a disk brake.

They apparently enquired about another run and got nothing, so clearly Schlumpf isn’t making custom freewheeling hubs or unicycle hubs.
Now someone just needs to find a 2 speed bicymple owner who wishes to part with it…

Super dangerous! Rolling at 25km plus per hour and freewheeling…

Honestly I don’t think it’d be that bad. I’ve done 25kph on my freewheel downhill and it felt fine.
Because you’re not spinning your cranks around madly, if you’re doing brake assisted freewheeling then that speed doesn’t feel all that bad.

There’s a 3.8 ratio on some geared hub

The JR Game Changer hub is 3.8x geared, but it’s single speed so not all that useful, and it requires a custom frame.