Updating the specs for a "standard" unicycle (Closed for comments)

Comments about this discussion:


Change is painful when there are a lot of 'standard' track unis out there already. But the specifications were made years ago and perhaps need updating. Here are some items for discussion:

  1. Tire/wheel size and how to measure it
  2. Brake/no brake
  3. crank length
  4. Pedals (clip-in allowed?)
  5. Gear ratios other than 1-to-1

Anything else?


Please let's have a serious discussion about moving to a "faster" wheel size for Track. The only reason we are still racing on 24" wheels is that back in the 70s and 80s, it was the largest size you could buy off the shelf. Those days are way over. I cannot see the point of "racing" on such slow unicycles! The one upside of that size is that, mostly, you can run out of dismounts at any speed. But on the other hand, doesn't that just mean they're too slow?

My Track unicycle is 31 years old. I had a nicer one, from the early 90s to 2000, but it got stolen at Unicon X and I'm back to my old, faithful 1981 Miyata (with its now-broken axle; still not fixed yet). But this is not about me buying a new unicycle; I already have lots of other sizes, plus I'm going to restore my old 24" no matter what! But Track racing lost its attraction to me in the late 90s when I realized most of my riding was done on a 26" wheel (before I got a Coker) and yet we were still "racing" on 24" wheels. That's silly.

So we developed a standard for 700c racing unicycles, and they were kind of a "side event" at Unicons 12 and 13. Didn't catch on. If we're going to make the change, we might have to bite the bullet and REPLACE 24" with a larger size.

WOAH! YOU CAN'T DO THAT, EVERYBODY WOULD HAVE TO BUY NEW UNICYCLES! THEY WON'T ACCEPT IT! You're probably right. To make it work, we would have to announce the change a year or more in advance. Nobody would have to buy something new, as the old wheels would still be allowed. People who really care about Track racing on unicycles would, of course, show up with new unicycles.

What size? Probably not 700c. There was a recent discussion on the Unicyclist.com Forums about using rim size, or BSD (Bead Set Diameter) as a size that would be much easier to work with. It would be nice to get away from having to measure tires, which is really hard to do quickly without making special devices to stick the wheel in.

What wheel size do people think makes sense for racing on an athletics track? Based on some testing, I do not favor 36". Heavy wheels, and fitting to the lanes while transitioning from the curve to the straightaway are problems. I think something in the 29" range is the right size.

Please comment on what you think about the idea of moving to a larger size for Track racing? For smaller riders, we would keep 20" (and maybe 24") but not for the grown-ups.


Response to Kenny's original post:

Tire/wheel size and how to measure it
Bigger size, hopefully measured by rim, to eliminate the need to measure tire diameters. If we do need to stick with diameters, which we might, The options I can think of are a measuring tape around the tire (hard to do quickly, especially by a single person), or a special tool that's pre-set to either stick the wheel in, or be slid over it (like a giant 2-prong fork).

Brake/no brake
This being the Track category, I don't see a reason to disallow brakes.

Crank length
Keep a minimum, no maximum. If we still don't have the will to go to a larger, faster wheel size (24" are kids' tires!), maybe we can go to 100mm for 24", and something proportionally smaller for 20".

Pedals (clip-in allowed?)
I'm not a fan of feet stuck to the pedals for Track. We have seen that it works, well, for Road racers but that's a very different environment. On the track things happen very fast, you're riding all out, and there will be other riders all around you. So for me, I still recommend against it.

Gear ratios other than 1-to-1
My short answer is no, but if you wanted to add events, separate from the existing, traditional ones, that might be interesting. I'd rather see geared unicycles racing longer distances, so basically off the track.


I believe the 2 prong fork is a great idea. It can be a simple rigid, non-metallic bar (thermal expansion) with 2 permanently affixed end pieces defining the max diameter of any wheel/ tire combination. If any wheel/tire combination at its widest point cannot fit between the two ends of the "Instrument", then, that wheel/tire combination shall be deemed illegal. The IUF can have these "instruments" certified and distributed.


It's not like the attendance at track racing with the current rules (24", 125 mm except for juniors) is dwindling, is it? Note that in road racing (if it is allowed to mention in this discussion) 10k standard has usually way more riders than 10k unlimited.

I conclude that the current rule for track racing fits with the desires of the majority of riders. It is telling that experiments with 29" wheels in track racing did not catch on.

If the larger wheel size of 29" is not picked up voluntarily, why enforce it? Who are you making happy?



What Klaas says is true. But perhaps we are asking the wrong questions. Of course there are lots of 24" riders in the 10k race. They already brought those unicycles to race Track, so they are availbe for the 10k. Why didn't they bring their 36ers? If you've flown with one, you know the difficulties. If you have one and have never flown with it, it could be because of those difficulties. It's a big deal to bring one, so less people do.

So the big question: Why do these people have 24" unicycles? What do they use them for besides IUF-style racing? Mine got used for three basic things, Track, the very rare (for me) basketball game, and short trips, such as to pick up or drop off a car being worked on near my office. Nothing else.

I have faster unicycles if I want to go faster. We are racing. We should be racing faster.

So ADDING a set of 29" races got a lukewarm reception because those same riders were still bringing 24" unicycles for all those juicy Track events. It meant bringing an extra unicycle. That's why I only think it will work if it is offered for the same array of Track races we do on 24". Perhaps the way to make the transition succeed would be to offer those races in both sizes. Of course you can only enter one or the other. Look at it this way; it might add some heats, but it would still be the same overall number of riders.  :-)


I for one have brought my 36" to several Unicons (for the marathon). My 36" would thus have been available for 10k, but I choose to enter the 10k on 24". In short: I prefer to compete on small wheels (if my competitors are on those small wheels too, of course). I'm not sure if this holds for many riders. But I do know that interest in 24" track racing remains high. Apparently not everybody thinks like John, quitting track racing because of the small wheel size.

At lower levels, e.g. at our Dutch Nationals, many competitors are not seriously into track racing and for quite a few riders, 24" is their biggest uni. Since that is the max wheelsize anyway, it makes an easy entrance to track racing. Move the wheelsize to 29" and those riders are discouraged. Remember the IUF rules are not only for Unicons.

It would be interesting to see what would happen if track racing were offered in 24" and 29" versions, mutually exclusive as John suggests. Perhaps on a Unicon first, as a test, as we find the most serious participants there. If it still wouldn't catch on (which, frankly, I expect), there's even less chance it would work outside Unicon.

(But hey John, are you sure it would be the same number of riders? I thought that your point is that many riders, at least yourself, have quit track racing because of the small wheel size? An't you coming back if you can race 29"?)



Klaas: "I choose to enter the 10k on 24"
I can see wanting to do that to race against your peers/friends, but otherwise, not so much. I wonder if there are more of me, or more of you out there? And of course the equation for that changes based on the travel required to get to the event. Next near, NAUCC will be within driving distance! So I will have more choices.  :-)

Klaas did bring up the interesting point that many of the riders at Dutch Nationals have 24" as their biggest uni. By country, there are probably very different answers to the question "Where do people buy their unicycles?" If they are shopping online they likely have more choices. If they are in a bike shop, it's more like the old days. And if they are in a club, they are more likely to choose sizes similar to what the other riders are using, which might mean still a lot of 24s.

Which goes back to the question of why people are choosing 24". If for Track racing, that will change if the size changes. If it's for other purposes there is more to know. If it's because that is what all their fellow riders use, it rotates back to the previous question but we can see the trend.

"Remember the IUF rules are not only for Unicons."
This is true. At the same time, Unicon is probably not the best place to test "conversion" to larger wheels for racing, again because of the luggage factor. It would probably be easier to do at the national level where, especially in smaller countries, people aren't flying to the event. But if the IUF isn't doing it, it would be hard to get it going anywhere if it doesn't ramp up to Unicon.

Are the Swiss still doing races on 26"?


Am I coming back if I can race on 29"? Yes! It's a whole new world then. New records to set (by younger people), and new learning of how to push one's limits on a larger wheel. And the IUF Slalom will be very interesting!  (Yes, of course I've tried it, at sizes up to 45" but that's not the same as racing it!)


@John Foss: no we're not racing on 26'' in Switzerland, that stopped at least 12 years ago!

I completely agree with Klaas statement: "I conclude that the current rule for track racing fits with the desires of the majority of riders. It is telling that experiments with 29" wheels in track racing did not catch on."

There have been so many chances (Unicon 13, Unicon 14, Unicon 16, Unioec 2015,...) for riders to ride on 29 wheels, the minority of unicyclists did it. That shows me that the interest of changing to bigger wheels is not existing. Just imagine how many riders we would lose if we change the wheel size. I estimate that at least 75% would not change to bigger wheels (me included, even though I love my 29 wheel!). Maybe your idea would work for 800m, maybe 400m races as well. But have you ever tried to do wheel walk on a 29 inch? I did, and I can tell you, you will definitely not be faster than on a 24! Slalom??? no comment! Believe me, I train the slalom at least 3 times a week, I've tried out a lot, I've experimented with crank length, with wheel sizes, and so on! Sorry, but it's NOT possible to race a slalom with a 29! Never! You can of course ride it, but you will never be able to race it in 18 seconds. That's the current world record, males even race it in 17.8! Think about it.

Furthermore I would like to consider the point of safety. At the speeds we race now it is possible to run if you dismount! A lot of younger riders however crash because they are not able to run after a sudden dismount. The speeds we have now allow these crashes but the faster you race the more likely it is that you crash and seriously hurt yourself. Think about that point as well. And again do not take 800m as an example, think about 100m races!


This is a good discussion! 

My question is are we solving any problems by making changes to the definition of a standard unicycle? So far the only plus I've heard is so the racers can go faster, but I don't see that in itself as solving a problem. In fact it could result in more track injuries since it would be more difficult to run out of a UPD. Having said that, I could possibly see allowing 100mm cranks. 


I personally like racing on 24" and spinning really fast.  Partly because of the level playing field but partly because you can't get that hurt.  I've UPDed full speed on a 24" slightly faster than I could run and only came off with a brush burn on my elbow (and if I had been wearing elbow pads would have been fine).  I can guarantee, full speed on a 29" you're going to get a lot nastier of falls.  Not to say there isn't a time a place to try to push how fast you can go on a unicycle of any size, but it is nice to have races that you can all out push with significantly less consequences.

I don't care for the idea of adding a 29" as a mutually exclusive race because it would make for difficult choices and more segmented competition.  As it stands right now in the 10k, I'm always torn between doing 24" which I really enjoy, or doing a 36" unlimited because at NAUCC pretty much all the adults do unlimited and only that one counts for overall distance awards.  Now I realize those things are more specific to NAUCC than Unicon, but you have similar issues where people have to choose one or the other partly based on what other people are doing.  If we add a 29" then in the 10k there are 3 choices, segmenting up the competition even more and in track there are 2 choices.


@Mirjam: "But have you ever tried to do wheel walk on a 29 inch? I did, and I can tell you, you will definitely not be faster than on a 24! Slalom??? no comment!"
Remember you are always allowed to use smaller wheels. But of course that brings us back to the problem of how many unicycles we are able to bring to far away competitions. And I believe you about the Slalom, I watched you compete in the Finals! Once upon a time, I was the fastest, from the year of the course redesign (1989) until I was eclipsed by Marc Hafliger at Unicon 11 (2002). I learned that a 20" could be just about as fast, but stuck with 125mm cranks the whole time. I can't remember what Marc used; he had several specialized unicycles just for the Track events, and dominated almost all of them that year.

I don't remember that 29" Track events were offered at Unicon 14, definitely weren't at U16, but your point is well made. If people wanted to race on bigger wheels, more of them would be saying something. So I will drop it. I just get worried about the lack of tires, and the possible abandonment of that wheel size by the bicycling industry. That will play out, and we'll see where it goes.

I also like the idea that crashing on 24" is relatively low risk. I even got some videos of top riders falling in the Expert 100m heats, but they seem to have worked out decent techniques for it, sliding on their bellies. Bigger wheels would clearly up the danger level, though not necessarily in an impressive way when compared to Trials, Downhill, etc.

Returning to the original topic of the thread, about Standard Unicycle definitions, I think it's important to be specific. There is no such thing as a "Standard" unicycle, except in the definition of a "plain" unicycle with no added features, like a geared hub, brakes, etc. Not sure if we have a use for that though. It probably needs to be specified per event category. Track (and 10k) have specific requirements, Standard Skill has different limitations (or lack thereof). So rather than the super-generic term of "Standard Unicycle" we should probably add a definer: "Standard Track Unicycle", "Standard Skill-Eligible Unicycle" etc.


Dear John, 


the underlying intention of your initial comment on further specifying the definition of a "standard unicycle" may be a good one, such that you intend to protect this generic term of being exploited by some tricky unicyclists. Nevertheless, there already exists a long-established procedure to measure wheel-size and crank-size before any major competition. To my knowledge people are already accustomed to this standard procedure and accept the judgment of the people carrying out the measurement process without complaints, given the fact that measuring a unicycle is an objective procedure and independent of subjective opinions. Consequently, your effort to include further specification requirements could be useful to simply include the measurement of a "standard unicycle" (24" wheel and 125 mm cranks) in the Rulebook (although I think this should already be mentioned somewhere). Any further intentions of specification, on the other hand, would only result in a too complex definition that would make matters far too complicated. 

Concerning your suggestion to open up competition for unlimited unicycles, I have to remind you that there is a good reason behind allowing standardized unicycles only. The only difference between competing riders should be their ability to ride and the hours spent on practicing. Opening up competition for any kinds of unicycles would completely distort this competitive environment and take away incentives for further training sessions. Therefor, this is highly counterproductive in creating any sporting competition and would only result in a "material war" of who can afford the most expensive unicycle. 

All in all I would ask you to keep the following in mind: There is always a way to enhance your performance on a unicycle and that is - practicing. After having completed your next race, you can be proud of your great performance due to your diligence, rather than buying an expensive unicycle that is better than the one of your fellow competitors. 


Regards, Lisa Hanny 


 Hurray to the direction the discussion is going.


@John: Unicon 14 in Denkmark (1500m), Unicon 16 in Brixen (100m)....

I like your point about the material war. We also have to consider that unicycling is a sport where you have so many different disciplines and you have a wide range to choose from. So if somebody doesn't like competing on a 24'', he or she has plenty of other options like muni, road racing, and so on. So at the end I think it's also important to still have an overview over all the different disciplines. I do not think that it is bad to have such a wide range but if we start adding standard, unlimited, 29, to every race it will end up in having small age groups and this doesn't make the races specatular either...


@lisa.h: "Opening up competition for any kinds of unicycles would completely distort this competitive environment and take away incentives for further training sessions."
No worries. My mention of unlimited in my previous post was in talking about the larger world of things we refer to as "Standard" unicycles; outside of the Track segment. I have no desire to add additional specifications to Track racing (unless people want to discuss a shorter crank limit).

@Miriam: "...if we start adding standard, unlimited, 29, to every race it will end up in having small age groups and this doesn't make the races specatular either..."
I agree, especially at smaller conventions. Much as I would like to see us go faster, I will wait until there is a more popular push for bigger wheels in Track.


It sounds like the only area that shows interest in possible change would be crank length. Here are my thoughts in no particular order:

  • Shorter cranks will provide faster speeds, at least after the start. Will these speeds be too fast to safely run out of?
  • Most kids learn using 125mm cranks, anything shorter may be difficult for them. But the rules would not force them to use shorter cranks.
  • Shorter cranks will make gravel and such more difficult. But again, that would be an equipment choice not a requirement.
  • Cranks are a relatively inexpensive "upgrade" without making travel more burdensome.

It's good to revisit this discussion every few years to make sure we take advantage of technological advances and the definitions remain relevant to the current state of unicycling. Having said that I don't promote changing the standard simply for changes sake, there must be a reason. Are we solving a problem, making the sport more enjoyable, appealing to newer riders, etc. I look forward to your feedback.


As Kenny requested feedback: I don't see a compelling reason to change the standard specs including crank length. Track racing continues to be very popular, and I don't hear any complaints from riders about the specifications.


Feedback #2: I completely agree with Klaas Bil. Never change a running system. And just developing this idea a bit further, all the work of the committee dealing with world record requirements would have been in vain, since all current world records would have to be adjusted and readjusted over and over again. Let's keep things simple and transparent. (Also with respect to other IUF-Committees)


As it's currently written, most of the standard sizes are specified with respect to the outer tire diameter:

Standard 700c - rim bead seat diamter (BSD) no larger than 622mm
Standard 24" - tire no larger than 618mm
Standard 20" - tire no larger than 518mm
Standard 16" - tire no larger than 418mm
(Side note, there is a typo in "diamter" under 700c that should probably be fixed)

What do people think of adding an alternative specification using rim bead seat diameter (BSD)?  I think the idea behind having an outer tire size limit is good because that's effectively what's contacting the ground and controls how far you go per revolution, but there are many issues with it (things like temperature, tire pressure, etc affect the size) and I think it limits some people from racing due to what tire they may have on their 24".  At the extreme, say someone has a 24" mUni (ex: http://www.unicycle.com/unicycles/mountain-unicycle/nimbus-24-inch-mountain-unicycle.html).  This doesn't conform to the 618mm limit so they can't race track, but I would argue that they are not at an advantage using this compared to something like the club 24" (http://www.unicycle.com/unicycles/cruiser-24-inch/club-24-inch-orange-unicycle.html).  The extra weight and rolling resistance of a 3" tire is going to be more of a disadvantage than the small extra diameter they get out of it.  With the current rule, I think around 24x1.95 is the largest that will fit, but expanding to allow 24x2.1, etc will allow more people to compete without giving any advantages (especially given that the elite are racing on 559 BSD with 1in tires).  The 700c is specified using BSD, so there is already some precedent and agreement that BSD is a reasonable way to limit.
Given that we've been using tire size, I don't think directly switching over to this is a good idea because you have so many people that own skinny tired 559 BSD unis made to fit to the current specification.  What I would propose is an additional way of measurement.  So the rule would be that it needs to meet one of the following criteria:
-The tire is no larger than 618mm
-The BSD is no larger than 507mm
This would mean that no current unicycles would become illegal, but it would allow things like 24x2.1 to compete. 


I like that, Danielle. It preserves the current standard but allows wheels that are probably less advantageous due to their greater weight.

My first 10k I was unaware of the wheel requirements other than 24", so I practiced on and brought my 24" Muni. Of course, I was told in no uncertain terms it would not do and was lucky enough to borrow a "standard" unicycle from a friend.

Is 24x2.1 a justifiable width limit, or should there be no limit at all?


I would say, keep only one limit, i.e. 618 mm diameter. With an alternative spec based on BSD (with no additional tyre width limit if I read Danielle correctly), a see a new materials war coming. People will find 3" wide tyres with low rolling resistance, buy a frame that accommodates it, and have a significant advantage. Until someone finds an even bigger balloon tyre, that is.

I would relegate all kinds of outrageously outfitted unicycles to unlimited road racing, but in Track (and in Road Racing standard class) it should be a single spec that is such that basically all expert riders ride the same or at least equivalent unicycles (which is the current situation with 618 mm).


I think one of the problems we are running into with this discussion is the multi-use nature of the "standard unicycle". In other words, are track requirements inherently different than road requirements, yet we are trying to shoehorn them into the same specification? If I know my history there weren't a lot of road races when the current standard was developed. 

Do we need a standard for track racing and a different one for road?


@lisa.h: "And just developing this idea a bit further, all the work of the committee dealing with world record requirements would have been in vain, since all current world records would have to be adjusted and readjusted over and over again."
Going to new standards is not the end of the world, and not necessarily a bad thing. We have done it before. We used to race in yards instead of meters, and crank arms were 5.5". Those two changes did not happen at the same time either. When it happens, it means a clean slate; or at least a chance to improve on existing records. Nobody really minds once the change is made.

In 1989 we did a complete redesign of the Obstacle Course (which we have since renamed IUF Slalom). The old course was much larger, but the newer version was small enough to squeeze into a typical tennis court enclosure. Times were about the same, but we got to start from scratch on setting new records. It took many years before somebody broke into the 18 second range on that new course! Again, up until 1984, the old course was measured in yards, so that was yet another change.


Re: BSD for 24" and smaller wheels, I have to go with Klaas. This is, in part, based on past discussions we've had in this committee about how to stick to a "good" 24" specification. Before we established our precise millimeter dimensions, the set size was an arbitrarily-chosen 24 1/3". Not very metric, so we rounded that to 618mm (and corresponding sizes for smaller wheels).

In Track, the idea is to race with very specific limitations on the unicycle's key dimensions, those being tire diameter and crank length. We give people the freedom to go smaller on tires, and longer on cranks, in part to allow participation if the rider doesn't have the exact equipment. But wheel diameter, especially, is the key factor in how fast a unicycle can go. While most Muni wheels are going to be heavier, their disadvantage diminishes as the race distance gets longer. A heavy tire would be a big problem in the 100m, but might almost be an advantage in the 800m, not to mention the 10k.

So we acknowledge the difficulty of measuring tire diameter, but we collectively felt it's a necessity at smaller wheel sizes. We've been more flexible with the 700c spec since it doesn't have a large following of people who already bought their equipment. The trend in the newer racing events has been to only set limits where we think they are necessary. Muni racing has always been completely unlimited in terms of wheel and crank size. For Road, we have categories for the unicycles people may tend to have already (Track and 700c), but usually the fastest times are done on unlimited wheels.

So, like Klaas says, there are indeed some lightweight balloon tires out there, and that's not the idea for Track racing.



I guess my aim at adding an additional specification isn't toward the expert riders, but rather all the other riders.  Track is a very nice gateway to racing since it's short distances and on a flat uniform surface.  For someone new to the sport, hearing that you need a 24" unicycle, like Kenny mentioned, it's very easy to arrive with a 24" that is actually illegal and not realize it.  For example, looking at all the 24" unicycles on UDC, I found 4 that come with larger than 24x1.95 that aren't mUni's:
Additionally, none of the 24" tires currently available on UDC are track legal.  My suggestion is to make it easier for new riders to race with the 24" they already have.  I agree that materials wars aren't ideal, but this is kind of what happened with the current 618mm standard.  People found a way to get 559 rims with 1" tires to just barely fit within the limit.  I think if down the road, someone found a way to make a 24x3" low rolling resistance tire that's faster than the 559x1, then so be it, that would eventually become the new standard.
One option to prevent crazy balloon tires is like Kenny suggested, have a tire limit with the BSD option but make it slightly larger, say 640mm (same as basketball).  I don't think just changing the 618mm limit to 640mm is good because it would leave too much room open for experts to take advantage of larger skinny tired wheels, but doing a combo of 507 BSD with 640mm tire makes it so that most 24" unicycles (aside from mUni's) would be track legal without detracting from the experts (I think you'd be hard pressed to make a unicycle with those specs faster than 559x1).


@Kenny: let's please have the same standard for track racing and for 10k road racing.

@Danielle: I continue to disagree. Serious racers don't by their unicycles off the shelve, so what's available as complete unicycles is not a good measure of what's possible. Also, while I haven't checked (maybe I should), I would be surprised if none of the 24" tyres currently available on UDC were within the 618 mm limit. So one cannot buy (or compose) a track-legal unicycle from UDC?


I agree that for serious racers, what's available stock doesn't matter since they will customize.  My main reason for suggesting the change is for the non-serious riders.  The ones who are at their first race and just getting into the sport.  I personally got hooked into the sport by going to an NAUCC that happened to be in my city that year.  Fortunately I happened to have a club 24" that was track legal but I very well could have easily had a sun or schwinn that wasn't.  I think that lightening up the restrictions on some of these slower 24" unicycles would open up track racing to a few more people than it's currently available without any detriment to the serious racers.

On UDC there are complete unicycles that are track legal, but none of the stand alone tires are track legal (they're all 3").  So if you currently own a 24" that doesn't have a track legal tire, you aren't able to purchase a replacement tire to make it track legal from UDC USA (it does look like many of the UDC sites for other countries do have track legal tires though).


@Klaas, I may have misinterpreted your most recent comment.  Are you suggesting that you think someone could potentially build something within a 507mm BSD and 640mm tire limit that is faster than the current 559x1 unicycles?  If it's the case that it could be faster, then I agree it wouldn't be smart to add a rule like I proposed.  I'm quite skeptical though that it could be faster.


Our existing tire spec is based on the "typical" tires that 24" unicycles came with at that time. 24 x 1.75, which was very common since Schwinn came out with theirs in 1967, and through the Miyata years, which are now over for most of the world. Yes, Schwinn 24 x 1 3/4, which was not the same diameter as Miyata but if I remember correctly, their tires measured out very close to 24", while the Miyata tires were more like 23 3/4".

Anyway, my point is that those tires aren't so common anymore. Most people riding 24" want a little more tire for riding on "more interesting" terrain. The reason they're doing that is because if they want to ride on pavement, there are bigger wheels. That was part of my thought process of pushing the larger wheel size, but I'm not doing that now. That needs to wait until more people are calling for it.

In the meantime, we should probably do a quick survey in our own countries, to see what's currently on the market for 24" tires. The choices have dwindled over the years, but I don't know where we are currently. If we can't find lots of availability within the 618mm spec, we might have to think about sizing up a bit...


@Danielle: indeed I think that a relatively wide tyre fitting on a BSD 507 rim is potentially faster than a tyre that just falls within the 618 mm diameter limit.
In the first few years of our Dutch Nationals we allowed bigger tyres so that people could compete using their Muni's. But to compensate for the bigger diameter, the crank length limit was proportionally increased from the standard 125 mm. After a few years we abandoned this system, because it was too complicated to measure, and also to get in line with IUF rules.

As to John's suggestion, typing "fietsband 24 inch" (without the quotes - fietsband meaning bicycle tyre in Dutch) into Google, I found lots of Dutch suppliers stocking 24" tyres of 1 3/4 inch wide, besides narrower and also wider types. No lack of choice here!


I can't edit, so to supplement my last post:

"we allowed bigger tyres" should be
"we allowed bigger tyres of nominal size 24 inch in our track races".


There has been no movement towards a proposal with this discussion. I will close it in the next few days until more discussion happens here.




Agreed as well.

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