Increasing the maximum wheel size from 618 to 640 mm

This discussion has an associated proposal. View Proposal Details here.

Comments about this discussion:


Ongoing from another discussion this will be a proposal about voting to change max wheel size to 640mm instead of 618mm


The pro's of allowing a 640mm tyre


  • Enables more participation from new riders who may not have a legal unicycle to take part without modification to their unicycle (even the Nimbus E-Sport 24"" Baskeball unicycle which looks like a decent all round unicycle if you want a 24" is slightly over 618mm
  • May increase participation from Unicycle basketball players as they are unlikely to have a hockey legal tyre and unlikely to swap tyres over to play hockey. Forces them to choose one sport.
  • May enable a league of some type in the future in basketball dominated countries (France) There are a few serious teams in France that I know of, they would struggle to set up a league and draw in more teams/players when most don't have a legal tyre.
  • For the moment it fixes most issues with "legal tyres"
  • 24" wheels are becoming less common in the bike world and with it less tyres. I know the Halo tyre was previously used as a good tyre with legal size however I think this is no longer made. Enabling a larger size enables a greater number of tyres to be sourced.

The cons of allowing a 640mm tyre

  • You are still going to have the problem of having to measure tyres that are near the maximum allowable size.
  • You will have to make a new tyre measurement box
  • Goalies will have more goal covered - yes this is true by a small amount. Everyone will be allowed to use the same size however and the goalie must weigh up the difference in harder to move their wheel quickly vs covering an extra 2cm of goal. Most good shooters should not be affected by the small increase.


The points that I think some people may believe are an issue but I don't think are.

  • Injury - From my experience there is no difference in out of control crashes on 24's compared to 20's. If you are good enough to get the tyre moving fast on a 24" you are good enough at stopping it. If you aren't good at stopping it you are also not good at getting it moving meaning you don't have faster speeds than someone on a 20". Most 24" riders I know get outpaced by riders on 20's. People who have tyres closer to 640mm are likely to be either basketball players, who are good riders and should be able to control their wheel and muni wheels - which usually have longer cranks and therefore will be hard to get going fast and have good amount of stopping control.
  • Everyone will start using 640mm tyres - There are only a select number using 24's, of all the people riding I dont think the extra 22mm allowance will sway many to chance from 20" to 24". For majority of riders who are on 24" they are unlikely to change their tyre to get the largest wheel, with a larger tyre comes greater effort to ride and turn, I have ridden a 24x1.95 regulary and a 24x2.5 during a few club games and the larger tyre feels bad to ride compared to the smaller wheel in my opinion.



I'm unsure on this.. Can see both pros and cons. If we do change this, I can't see many people using them anyway.. But I see how this can benefit countries like France, where basketball is more common over hockey.

I can remember when the UK league used to be active, we would sometimes have problems with 24" wheels, where riders were going too fast for what they could handle and struggle to stop.. The speed wasn't just an issue, but the size of the wheel was also getting in the way.


I have seen more people failing to control riding 20" unicycles with 89mm cranks than people riding 24" unicycles. Bad riders can get a 20" with 89s going fast better than they can get a 24" with 125s going fast due to the short cranks vs longer cranks.

In our league there are VERY few crashes with 24's (obviously there are less of them) but mainly because the riders who are quick can control them and the riders who are not good with control cant go quick enough as they aren't good riders. 

The point of the wheel size is to "get in the way" it is a tactical decision to have a larger wheel. The downside is you are not agile and 20" unicycles can out turn you. In the rules people must avoid contact so if someone is getting in the way in that sense they will be penalised for it.



Additionally we are looking at a very small increase. It is not like we are going from 24" to allowing 29" unicycles in hockey.



1. How many injuries are caused by 24"s now?

2. How many injuries are caused by 20" unicycles now?

3. How much increase are you expecting to 24" caused injuries from an increase from 618-640mm.

I think the answers to both 1 and 2 is almost none as we have a very safe sport, and there are probably more caused by 20" purely based on the frequency of use. The answer to 3 I think would be a very small amount.


I agree with you Steven and see no issues with making the wheel size a tad bit bigger. 


Go for allowing  640mm tyres!


Hey Rolf can you accept this




There has already been a lot of discussion here and I don't think any more is necessary.

I will be moving this to a vote tomorrow, unless there is strong disagreement.

Copyright © IUF 2016