Proposal 85: Definitions of Unicycle in 1D.1 [ Revision 4 ]Committee: Main Committee
Submitted on 2019-05-23
Status: Passed on June 12, 2019
The definition of Standard Unicycle is confusing, because it is often thought of as a unicycle allowed in Standard Class races.
Unicycle, Standard: A Standard Unicycle has only one wheel. It is driven by crank arms directly attached to the wheel’s axle/hub, with no gearing or additional drive system. Pedals and cranks rotate to power the wheel. Is balanced and controlled by the rider only, with no additional support devices. Brakes and extended handles/handlebars are permitted. For some events, such as track racing, standard unicycles have restrictions on wheel size and/or crank arm length. Other events may specify other restrictions. When not noted otherwise, there are no size limitations.
Unicycle, Unlimited: A Unlimited Unicycle is powered, balanced and controlled by the rider only. Gearing, shiftable or not, and/or freewheel are allowed. (This may also be referred to as ‘Transmission.’) Multiple wheels are permitted, but it must not be possible to ride the unicycle when more than one wheel touches the ground.
Unicycle, Wheel Size Classes: The IUF defines standardized wheel sizes classes for unicycling competitions. Each class can have a limit on the maximum allowable outer wheel diameter (maximum diameter), the minimum allowable crank arm length (min crank length), and allowable transmission system, as defined above in the Standard and Unlimited Unicycle definitions.
Unicycle Class Max Diameter Min Crank Length Transmission
16 Class 418mm 89mm standard
20 Class 518mm 100mm standard
24 Class 618mm 125mm standard
24+ Class 640mm No limit standard
29 Class 778mm No limit standard
Unlimited Class No limit No limit unlimited
For any tire in question, its outside diameter must be accurately measured.
Crank arm length is measured from the center of the wheel axle to the center of the pedal axle. Longer sizes may be used.
The maximum diameter for the 24+ Class and 29 Class are defined such that virtually any commercially available tire, 24 inch or 29 inch respectively, should fit under these limits. However, this is not guarenteed and the referee should still be aware of the limits.
Unicycle: A Unicycle is a vehicle that has a single rolling contact with the riding surface. It may have multiple wheels, but it must not be possible to ride the unicycle when more than one wheel touches the ground. It is driven by pedals and cranks which rotate to power the wheel. It is powered, balanced and controlled by the rider only, with no additional support devices. Unless noted otherwise, a unicycle may be fitted with handlebars and/or brake(s).
Regular Unicycle: A regular unicycle is a unicycle with only one wheel. The cranks are fixed directly and permanently to the wheel's axle. (This excludes unicycles with gearing even if in 1:1 ratio, a chain drive and/or a freewheel.) Unless noted otherwise, there are no wheel size and/or crank arm length limitations.
[Note for the editor, not intended as literal rulebook text: all instances of "standard" throughout the Rulebook that refer to "unicycle" should be changed to "regular".]
The definitions of Unicycle, Standard and Unicycle, Unlimited are replaced by definitions of Unicycle in the wider sense of the word, and Regular Unicycle which more or less corresponds to the former Unicycle Standard.
Unicycle Wheel Size classes, as well as defining Unicycle Unlimited, has been deleted here. It also occurred in Chapter 2, 3 and 4, and it remains there, albeit with some changes that are subject of other proposals.
Parent discussion: https://iuf-rulebook-2018.committees.unicycling-software.com/discussions/160
Some other relevant comments in: https://iuf-rulebook-2018.committees.unicycling-software.com/discussions/149
- Revision 4 changed by Klaas Bil (31 May 16:08)
In the previous revision, I had not changed
"A Unicycle typically has only one wheel"
"A Unicycle is a vehicle that has a single rolling contact with the riding surface",
although I mentioned in the Change description that I had done so.
Sorry, that was an oversight. I have changed it as yet.
- Revision 3 changed by Klaas Bil (26 May 12:59)
1. Added "unless noted otherwise" to the statement that handlebars and brakes are permitted, because this is sometimes not allowed, see e.g. 8B.2.
2. Added "is a unicycle" to the first sentence of the definition of Regular Unicycle, to make explicit that the definition of Regular Unicycle builds on that of Unicycle, so that everything that is defined for Unicycle also applies to Regular Unicycle.
- Revision 2 changed by Klaas Bil (24 May 17:00)
1. First sentence of definition of Unicycle changed from
A Unicycle typically has only one wheel.
A Unicycle is a vehicle that has a single rolling contact with the riding surface.
2. Added a note that all relevant instances of "standard" when referring to "unicycle" should be changed to "regular".
- Revision 1 changed by Klaas Bil (23 May 13:07)
Votes on this proposal:
21 out of 23 voting members have voted.
Agree: 21, Disagree: 0, Abstain: 0.