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.
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?
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 (March 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.
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.
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 from July 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), and d’brake mounts are not generally recommended due to flex and vibration that is less than ideal on a freewheel.
Right now, ideally the JR P-Hub due to it having the best build quality, smaller engagement from a finer ratchet ring, and (currently) no complete failures.
Alternatively the Nimbus Drift Trike Disk Hub, or Madazz Trikes Freewheeling Pedal Hub. These are both the same hub, 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 these hubs are square taper (cotterless) and as such require square taper cranks to go along with them.
Are there any better hubs? Square taper is old-school!
Not yet. Qu-Ax are planning to release a hub in 2021 but COVID-19 has caused many production delays across the industry. This hub uses a sprag clutch (which provides instant engagement), and the Qu-Ax Q-Axle interface for cranks - a vast improvement over our current square taper options.
Any other options? I already have a load of ISIS cranks, can I use those somehow?
Sadly not at present. Right now your options are square taper, or the future Q-Axle hub.
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 do a straight hub swap (to either the aforementioned Nimbus/Madazz or JR hubs). Other wheels 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?
Yes, if using a standard frame designed for 42mm bearings then you will either need bearing shims (sold by UDC), or replacement bearings (17x42x12 - often available on eBay).
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 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.