Freewheel Unicycling Megathread

Freewheeling unicycles - The future?

People have been building freewheel unicycles for many years now so it’s about time we had a proper thread for all of the useful information.

Please post below anything freewheel related, especially anything that’s missing from these initial posts so I can keep them up to date and relevant.

General FAQ

Terminology - What do we mean by a freewheel unicycle?

A freewheel (or freewheeling) unicycle, as the name suggests, is a unicycle that freewheels. These typically use a hub with a clutch, which only engages when you’re pedalling forwards.
This means that when you stop pedalling, the unicycle wheel continues to rotate.

Unlike a BC (impossible) wheel that freewheels in both directions and has no method of propulsion or seat, “freewheel unicycle” normally refers to a unicycle with a seat and pedals.

Some people have built freewheel unicycles without pedals rather BMX pegs to put your feet on, but they are even more uncommon than ones with pedals.

Why would someone want a freewheeling unicycle?

Like most questions about unicycling, the short answer is “why not?”

The longer answer is that it’s another skill to learn, and with practice provides rather a different experience and allows you to ride in a way that no other unicycles do.

Are they harder to ride than a fixed wheel unicycle?

Yes.

Where can I buy one?

Right now, complete freewheel unicycles are not available new. Unicycle.com briefly sold one some years ago but as of right now (July 2021), they have to be purchased either second hand, or built up from parts. Your favourite unicycle supplier may also be able to build up a complete unicycle for you if they have the parts in stock.

Build FAQ

What size?

People have built freewheels from 20" to 36" so go with whatever you think will work for you. Generally 24"-27.5" would be recommended if you’ve not got a specific size in mind already.

Which frame?

Any 100mm bearing spacing frame with disk brake mounts on the left (internal) side. Nimbus Oracle (up to 29"), Qu-Ax RGB, Qu-Ax QX Series, Mad4One Muni/URC Muni, Flansberrium etc.
Nimbus also have a 100mm dual disk 36" frame coming soon (expected to be available late 2021).

KH frames are not compatible as the disk mount is on the wrong side, although you can weld a tab onto the appropriate size - UDC (UK) sells a kit for this use with the Schlumpf BrakeFast.
D’brake mounts can be used, but are not generally recommended due to flex and vibration that is less than ideal on a freewheel. The now included stiffener plate is an improvement but not a perfect fix.

Which hub?

It should go without saying that to build a freewheel unicycle, you need a freewheeling hub.
As nobody is making a unicycle specific freewheel hub yet, we have to look elsewhere and think a little bit outside of the box.

At this moment the best hubs to use are either the Bicymple 1:1 freewheel hub (ISIS), or the JR Drift Trikes P-Hub (square taper).
This is down to the number of clutch engagement points (24 for each), and so far the lack of failures of these hubs.

Alternatively the Nimbus Drift Trike Disk Hub, or Madazz Trikes Freewheeling Pedal Hub. These are identical in design, and although they’re not quite as good as the JR, plenty of riders use them with no issue. Hardcore riders do have a habit of splitting the hub shell in two though, especially when riding with long cranks, so be careful!

All of the aforementioned hubs are square taper aside from the Bicymple one.

Are there any better hubs? These hubs don't seem to have been designed to handle abuse.

Qu-Ax were planning to release a unicycle specific hub in early 2021 but COVID-19 has caused many production delays across the industry. This hub uses a sprag clutch which provides instant engagement and is therefore an improvement over the 18 or 24 engagement points of other hubs, and the Qu-Ax Q-Axle interface for cranks - a vast improvement over the square taper options. Now this hub is expected late 2021 or early 2022.

Can I just modify my existing unicycle/wheelset?

Yes, and many people have done exactly this. If going from a stock 100mm Nimbus Oracle or KH wheelset, the spoke lengths required are close enough that you can generally do a straight hub swap (to either the aforementioned Nimbus/Madazz, JR, or Bicymple hubs). Other wheels or hubs may require new spokes depending on their original hub dimensions.

Can I build without a brake?

Yes, but the same hubs would be recommended if you can get them. Obviously then you have more frame options if you’re not considering adding a brake in the future. You could even use a frame designed for square taper hubs with 40mm bearings (see next question).

Do I need to do anything else to make this work?

If you’re using a standard frame designed for 42mm bearings (designed for ISIS or Q-Axle hubs) then for all of the square taper hubs you will either need 1mm bearing shims (sold by UDC), or replacement bearings (17x42x12 - often available on eBay).

If you’re using the Bicymple 1:1 ISIS hub, then you must ensure that you use crank spacers. This is even more important than on a fixed wheel because not only will you likely damage your cranks without, the hub itself will come apart if the spacers are not there to hold it all together. Spacer length will depend on your specific crank choice (~2mm less than the distance between the bearing and the inside of a crank pushed on by hand).

What cranks, at what length?

For either the Nimbus/Madazz, JR P-hub, or other drift trike hubs, you will need square taper (cotterless) cranks.
For the Bicymple hub you need standard ISIS cranks (common on most higher end unicycles).
For the future Qu-Ax hub you will need Q-Axle (or Shimano Hollowtech II) cranks.

As a general rule, go for one size shorter on the length than you would go with a fixed wheel. Extra length is only useful for uphill as if you want to slow down, your brake has to do all of the work.

Can I use x/y/z part or do x/y/z not mentioned in this FAQ?

Absolutely give it a try and let us know how it goes! Freewheel unicycling is very much a new part of our sport and we’re all learning all the time. There’s a wealth of information on this forum about weird and wonderful possibilities too - have a search and see if anyone’s had similar ideas.

Does anyone sell an off-the-shelf freewheel unicycle/wheelset that I can buy?

No, but Qu-Ax may do in 2021 and others may follow. Your local bike shop should also have no issue doing the build/modification for you if you’re not keen on DIY.
Your favourite unicycle supplier may also be able to build up a complete unicycle for you if they have the parts in stock.

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[Work in progress post - Learning and Techniques]

Learning and riding without a brake
AJ has done some great tutorial videos on getting started without a brake:

Learning and riding with a brake
Learning to ride with a brake is easier than without, however this is potentially done at the expense of improving your balance as quickly and may slow your progress later on.

Brake Control

Brake control is the biggest part of the learning process when coasting with a brake, and this is something that you can learn without even owning a freewheel!
If you’re already confident with a brake then you may find that your progression to actually riding a freewheel is pretty straightforward.
Whatever your unicycle, if you have a brake then by using it regularly you can be improving your braking skills with a goal of progressing to a freewheel in the future.

Learning without a freewheel - Brake Coasting

One thing you can practice without a freewheel to improve your braking skills is brake coasting. This is when you take your feet off the pedals entirely, and use your brake to balance.
To start, try using your brake heavily when getting off the unicycle, allowing the unicycle wheel to do a number of revolutions without your feet on the pedals, before putting your feet down on the ground. From that point you can start pulling harder on the brake at the end of this coasting period to bring the unicycle back upright and continue riding.
This is easiest when going downhill on smooth terrain, but with sufficient speed and/or braking skill this can be practised almost anywhere.

Brake Coasting on a Unicycle - Corbin Dunn Brake Coasting in 2011 [YouTube]
A Coasting Dream - David Weichenberger Brake Coasting in 2014 [YouTube]

Practising on flat
@toutestbon made a great video in 2017 showing a variety of different mounts and tricks:

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[Hubs/Ideas/DIY/Oddities]
In this post, freewheel parts, DIY parts, and anything that isn’t quite a freewheel unicycle, but could be…

Unusual bicycle hubs:

Bicymple 1:1 ISIS Freewheel Hub


Internals

Summary
The first available ISIS 1:1 freewheel hub.
ISIS spindle
100mm bearing spacing with standard 22x42x12 bearings.
24 points of engagement.
This hub has been weighed at approximately 590g (incl. bearings, without bolts), 639g (incl. bearings, incl. 12mm bolts).

Availability
None - we bought them all.
Bicymple are investigating the manufacture of more, but with COVID this might take a long time.

Usage
This hub can be used as a straight swap in any internal disk unicycle frame without modification or bearing shims. Normal ISIS unicycle cranks can be used, but crank spacers are essential to stop the hub coming apart during riding.
So far a handful of riders have these hubs with reports that aside from the ISIS cranks and smaller Q-factor, there’s very little difference in feel from the JR P-Hub (see below).

Issues
The hubs use M15x1 axle bolts, that although they conform to the ISIS spec, are an uncommon size on unicycles (we normally use M12x1).
ISIS crank spacers are essential. There are two bearings press-fit into the hub shell which although may stay in place initially, require the use of crank spacers to ensure they don’t come out of the hub.

Spacers
From user testing, the following spacer dimensions can be used as a guide:

Cranks Condition Spacer size
Bicymple 152mm New 8.5mm
KH Spirit New 8mm
Mad4One 10-pin Used 8.5mm

Maintenance
To maintain the clutch on this hub, the clutch side sealed bearing must be removed from the hub. This is a press fit so may not be trivial to do. The axle pushes out towards the clutch side - pressing/hitting the disk side of the axle should make it fall out of the clutch side of the hub.

Drift Trike Hubs:

Nimbus/Madazz Drift Trike Hub

NimbusDriftTrikeHub
Summary
This hub has 100mm bearing spacing, with a square taper axle, and optionally a standard 6 bolt disk brake mount. It comes in black (Nimbus/Madazz) or Orange (Madazz only).
UDC lists a weight of 618g.

Availability
Limited
The Nimbus hubs are no longer in production - some stores still have stock.

Usage
This hub used to be commonly used for building freewheel unicycles due to its reasonable availability from unicycle.com and other suppliers. It also has close enough hub flange dimensions to be used interchangeably in stock Nimbus/KH wheelsets without requiring new spokes.
To use this in a frame designed for ISIS hubs with 42mm bearing holders, you require 1mm shims, or replacement bearings (17x42x12)

Issues

  • The clutch in this hub has only 18 points of engagement, which can mean that a moderate amount of pedalling is required before engagement.
  • The hub shell is not very thick, and under hard pedalling has been known to crack in half on numerous occasions. Therefore this hub is not generally recommended for use off-road, especially with long cranks and uphill usage.
  • The axle is square taper which means a limited number of strong cranks are available and it may not hold up very well over time, especially off-road. This has however not yet been an issue - the hub shell cracks first!

Maintenance

  • Bearings don’t last forever - they should be always coated in a light coat of oil or grease to reduce surface corrosion, and they may need replacing every few years depending on riding conditions and distance.
    To remove the bearings, both circlips must be removed. Circlip pliers are highly recommended to avoid damage.
  • The hub should ideally be checked for wear, and cleaned and re-greased regularly to ensure a long and reliable life. This should probably be done every 500-1000 miles with the amount of abuse that unicycling can give to these hubs that were not designed for it. To do this, the non-clutch (disk) side circlip is removed, and the axle can then be lightly knocked out from that side.
    To re-install, spin the axle in the freewheel direction while re-inserting and the pawls should automatically retract and slide into the hub shell, then reinstall the circlip.
JR Drift Trikes P-Hub

Internals:


Summary
This hub has 100mm bearing spacing, with a square taper axle, and a standard 6 bolt disk brake mount. It comes in black or purple.
This hub has been weighed at 690g.

Availability
Limited
This hub is as far as I know no longer in production. Stock is limited.

Usage
This hub has commonly been used for building freewheel unicycles due to its general superiority over the aforementioned Nimbus/Madazz hub, although the Bicymple hub is expected to be a superior choice in the future. It has close enough flange dimensions to be used interchangeably in stock Nimbus/KH wheelsets without requiring new spokes.
To use this in a frame designed for ISIS hubs with 42mm bearing holders, you require 1mm shims, or replacement bearings (17x42x12).

Issues

  • The clutch in this hub has only 24 points of engagement, which although better than other hubs, can mean that a moderate amount of pedalling is required before engagement.
  • The hub flanges are very close together, which means that larger wheels especially have limited strength compared to a standard unicycle wheel. So far this has not been an issue even on wheels up to 32" (ridden on road), but is something to bear in mind.

Maintenance

  • Bearings don’t last forever - they should be always coated in a light coat of oil or grease to reduce surface corrosion, and they may need replacing every few years depending on riding conditions and distance.
    To remove the bearings, both nuts must first be removed. The disk side nut is right hand thread, and the clutch side nut is a left hand thread (reverse thread).
  • The hub should ideally be checked for wear, and cleaned and re-greased regularly to ensure a long and reliable life. This should probably be done every 500-1000 miles with the amount of abuse that unicycling can give to these hubs that were not designed for it. To do this, the non-clutch (disk) side nut is removed, and the axle can then be lightly knocked out from that side.
    To re-install, spin the axle in the freewheel direction while re-inserting and the pawls should automatically retract and slide into the hub shell, then tighten up the disk side nut (a spanner can be used carefully on the square taper axle as something to tighten up against).

Onyx Racing Drift Trike Hub


Summary
Onyx Racing makes Sprag Clutch bicycle hubs, and briefly made a short run of square taper drift trike hubs with sprag clutches.
Presumed to be 100mm spacing and standard 17x40x12 bearings for square taper hubs.
Expensive when available ~$500, and unavailable without a new order with MOQ of likely >5 units

Availability
None
No longer in production, never seen second hand.

They apparently could make us ISIS ones, but they’d come in at ~$700 with a MOQ of 10 units.

Unicycle Specific Hubs - soon:

Qu-Ax Sprag Clutch Freewheel Hub


Summary
This is a prototype hub made by Qu-Ax being tested by Becky Wiedener and Florian Kaiser. This is the first freewheel hub that has been designed from the ground up for unicycling.
This hub has 100mm bearing spacing and 42x12mm bearings to fit into standard ISIS/Q-Axle frames.
It uses the Qu-Ax Q-Axle crank interface, an instant engagement sprag clutch, and has a standard 6 bolt disk pattern.

Availability
None
Not yet in production. ETA Q4 2021/Q1 2022

Usage
This is expected to be the best hub for freewheel unicycle usage once released and should be a drop in replacement for non-freewheel hubs (although new spokes may be required).

Issues
Unknown - some issues have been experienced during testing but this is normal for any prototype product and these are expected to be fully resolved in the production version.
Due to the engineering involved in producing such a hub, we’re not expecting it to be cheap. It’s likely that it will be significantly more expensive then Qu-Ax’s current Q-Axle hubs.

DIY Hubs/unusual freewheel unicycles:

DIY Freewheel Hub - AWS

@aws has made his own ISIS freewheel hub with two sprag clutch bearings:
Freewheel Unicycling Megathread - #40 by aws

Not a unicycle:

MC² Transformer Bike


This is an interesting bike that first appeared in 2014 as crowdfunding campaign, went on to full production, then the company went quiet more recently.
Most interesting to us unicyclists is the front wheel, complete with of a two speed geared freewheeling hub.
The bearing spacing is unknown, but it’s presumed to be close to 100mm, and it appears to use standard 17x40x12 square taper axle bearings.

The shifting appears to work by means of a free-spinning planetary gear set (for 1:1), with an outer ring gear that’s locked in place to go to the high gear (1:3). In the prototypes this locking mechanism was a secondary disk brake, but the finished products appear to possibly use some kind of drum brake or enclosed disk arrangement.
With some imagination one can see how this same idea could be used to create a freewheeling/fixed hub complete with hand controlled shifter. If there is enough modulation in the “gear changer” then this could potentially be used as a rudimentary CVT, or at least allow you to slowly change gear rather than jump from 1:1 to the slightly insane seeming 1:3.
The gear change is demonstrated in this video: MC2 bike Direct Wheel Driving system - YouTube

https://www.mc2bike.com/store/p11/MC²_DRIVING_WHEELSET.html (website working July 2021)

Bellcycle

This is another crowd funded product that went on to full production, but it was only ever sold as a kit of parts.


It utilises an extra wide square taper axle complete with chain drive in a similar manner to some DIY geared unicycles but with a freewheeling sprocket connected to the driving wheel.

http://bellcycles.com/ (website working Jan 2021)

Kervelo Bicycle Hub

This was a hub designed for a recumbent bicycle by the company Kervelo.
It consisted of a Pinion P-line gearbox with single sided mount and a huge custom cage hub and wheel surrounding it.
This never looked like it would be the strongest design around, but it was a fascinating concept and it presumably worked on a recumbent!

It used ISIS cranks, would have been at least 2.7KG (the weight of a Pinion gearbox), and due to the single sided mount, almost certainly not strong or stiff enough to ride as part of a unicycle.

Kervelo kernel-hub

Following the apparent success of their previous hub prototype with a Pinion gearbox, Kervelo then went on to create the Kernel Hub, a 6/12 speed internally geared hub complete with ISIS cranks and pretty normal looking spacing, but with a somewhat unusual looking mounting setup.


Sadly despite apparently going into production, this disappeared as fast as it appeared and it never seems to have actually been sold.
https://www.kervelo.com/transmissions/gearhub-kernel-hub/ (web-page no longer exists - 2021)

Bicymple

Another front wheel drive bicycle that went into production, using either a freewheeling Schlumpf 2 speed hub, or their own custom made ISIS 1:1 freewheel hubs.

https://shop.bicymple.com/products/bicymple-penny-farthing (Website working Jun 2021)

Unibike

A number of BMX riders over the years have removed the rear of a bike with front stunt pegs to create a “unibike”.
This is what we’d call a peg freewheel now, but with handlebars instead of a seat.
Robin Eriksson Unbike - YouTube

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[Work in progress post - History, notable, and showcase]

Historical discussion threads:

Freewheel Unicycle - 2006
26" freewheeling unicycle - 2007
Freewheeling KH24 - 2007
Freewheel hub design - 2008
Freewheel 36er - 2013
Adventures in Freewheeling - 2013

Riding Videos:

Offroad/Downhill

Freewheeling the Anza Trail, 36" Edition - Carl Hunt - February 2013 [YouTube]
Downhill Dream - Carl Hunt - April 2014 [YouTube]
Unicycle Freewheel - Tibo Waza - June 2016 [YouTube]
Ben Soja - Jan 2018 [YouTube]
Coasting Duthie Hill - AJ Kinsella-Johnson - Jan 2018 [YouTube]
Almaty Trail 2019 - Dmitry Bibichkov - Aug 2020 [Instagram]
Freewheel Revolution - Rebekka Wiedener - Jan 2021 (Qu-Ax prototype hub) [YouTube]

Jumps/rollers

Small Jump Practice - Carl Hunt - May 2014 [YouTube]
No pedalling - AJ Kinsella-Johnson - July 2019 [YouTube]
Big jumps - AJ - Feb 2020 [Instagram]
Landing jumps - AJ - March 2020 [Instagram]
Progress on the freewheel - Samuel Mößner - October 2020 [Facebook]

Urban/Skatepark

Tibo Waza - January 2018 [YouTube]

Road/Distance

32" à roue libre au Grand Roquet - Simon Jan Du Voyage - Nov 2016 [YouTube]
Freewheel unicycle training in my street - Simon Jan Du Voyage - Dec 2017 [YouTube]
J’ai croisé le Père Noël à Saint-Malo - Simon Jan Du Voyage - Jan 2021 [YouTube]

Other

3.8x Geared Freewheel - Carl Hunt - March 2015 (JR Game Changer Drift Trike Hub) [YouTube]
Peg Unicycling - Carl Hunt [YouTube Playlist]
Freewheel Unicycling - General - Carl Hunt - [Youtube Playlist]

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Not totally true, Romain from the CDK shop, France, still has a few new Nimbus hubs. If you’re in Europe you can purchase one there :slight_smile:

That was meant to be regarding complete unicycles rather than just the hubs - I’ll update to make it clearer.

It’d be impossible to keep up to date with hub stock.

Sure. However he can build a complete unicycle with this hub - he’s done one for me two months ago :smiley:
But, yes, I see what you meant. BTW, great thread. Thanks for your involvment in this discipline!

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Absolutely - that’s that the Build FAQ is for! :grin:

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I’ll add a note to say that suppliers will often be able to build up from parts if they have hubs in stock.

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Thanks for starting this thread @mowcius

Great work, @mowcius! Let me contribute something related to the JR P-hub: disc side nut is right-hand threaded, non-disc side nut is left-hand threaded. (I just needed that haha)

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I have the following, but it could probably do with being rearranged somehow:

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Adventures in Freewheeling - 2013

Too bad waalrus’ Youtube channel is shut down. There was a lot of great freewheel videos there. Anyone knows him and can ask?

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He reuploaded some of them here.

I linked some of them in the Riding Videos section.

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Today, I converted my 26" freewheel muni, which I had been using for more than 3 years, to 29"! First ride went pretty well, the 29er fits my local terrain very well (trails with lots of roots and mud, dirt roads in between). I kept the 125 mm cranks.

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When I went off social media a few years ago I deleted the videos that were in my old YouTube account. As you discovered I reuploaded some of them into my regular Google account. I purposefully didn’t upload all of them but I’ll look through and see what I else I can find. They could stand as a “what not to do” in terms of freewheel unicycling since I spent years and thousands of miles on techniques that were not so good.

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Happy to have you back with us!

Do you ride freewheel much these days?

Whatever you think of your techniques, your videos definitely helped to inspire many of the current generation of riders!
Just seeing you ride off-road got my mind obsessed with the possibilities.

If I remember correctly you had a video with you riding a 36" freewheel. I’d be interested in seeing the free mount.

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There used to be a video somewhere of someone (possibly in China?) riding a 36" freewheel too, but I can’t find it now.

There’s are two great 32" mounts in this video at 0:33 and 0:49:

And two videos from the freewheel 36" thread with brakeless mounting:

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There are two different angles of the mount at the beginning of this video in addition to those interspersed throughout.

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