IUFSlalom  changing the max. cone dimensions (change 2B.8)
This discussion has an associated proposal. View Proposal Details here.Comments about this discussion:
Started
This topic was already discussed in the last rulebook committee, but in the end no vote was made, because in the discussion it was suggested to first collect what dimensions common traffic cones can have. Now a few years have passed since the last rulebook update and I have tried to find out what sizes traffic cones can have. Unfortunately, apart from the European standard I already mentioned last time, I have not been able to find any other standards that explicitly specify dimensions for the base plate and I have no way to measure nonEuropean cones to see if they are even larger than the European standard would allow.
From my point of view, therefore, the main problem that remains is the one already mentioned last time:
The dimensions of normal road traffic cones in Europe are specified in the standard EN 13422:2004+A1:2009. This standard stipulates that "If the thickness of the footplate at the outer edges of ≤ is 15 mm, the base shall be within a circle 0,9 H in diameter of the cone". For the 50 cm high cones normally used in road traffic, this means that the outer edges of a square base shall not exceed 31,8 cm.
In Germany the manufacturers use these dimensions and the usually available cones therefore have an outer edge about 1.5  1.8 cm too long to be used for competitions according to the IUF rules. This circumstance makes it in Germany unnecessarily complicated and it would be a simplification for the organisers of competitions if the cones usually available could be used. I am therefore would strongly recommend raising the dimensions of the base plate to a maximum of 32 cm square.
As I already wrote in the last committee: In training and also most competitions in the last years in Germany we used almost exclusively the normal road traffic cones and the minimally larger base size has never been noticed negatively. According to all my experience, the distance of the pedal to the upper part of the cone is the limiting element of how close you can get to a cone and not primarily the size of the base. Of course, the base must not become too big, but as I said during our training and commpetitions, the larger base has not yet attracted any negative attention. Probably, because you still hit the cone with the pedal first and not the tire touches the baseplate first.
Comment
I would disagree that the base plate size doesn't matter. I have a video of the current world record by Mathias Bracke. In the five cones in the centre (# 3 to 7) his unicycle is quite upright, and he almost shaves the baseplates with his tyre, especially on the three middle cones. With the other cones a larger base plate would be no problem because the unicycle is at a large angle from vertical.
This is not to say that I am against changing the dimension requirement, just trying to raise awareness. OTOH, with max 32 cm we may be requiring what is already being used in practice.
Two questions:
(1) Would we allow other base shapes than squares? At the Dutch nationals we use a set of cones that have hexagonal base plates.
(2) Do we need to specify the orientation of the base plates? I assume that swith quare bases, they are parallel to the main lines (such as the start line)? The Rulebook depicts the cones as circles.
Comment
Could you share the video with the committee? My experience so far has always been that if you want to get to the base plate with the tire, the pedal will definitely knock the cone down, because it must touch the cone  at least with the cones that I have seen so far.
Which is actually quite logical, since the outer edge of the pedal is about 1920 cm from the tire of the unicycle, and since the cone has a certain thickness at the height of the pedals (about 78 cm), the pedal must touch the cone even in the fully upright position if the tire is to touch the baseplate.
(Assuming the smaller dimensions, if the unicycle is perfectly vertical and the padale just touches the cone, the tire would be 22.5cm from the center of the cone, which is virtually the diagonal dimension of a perfectly square base plate measuring 32x32 cm).
In addition: The cones that are frequently used here in Germany do not have a completely square baseplate, but a square one with beveled corners. The standard does not specify this, but all new cones according to the corresponding standard that I know of are equipped with these beveled corners. The edge length of the cones is thus theoretically a maximum of 32 x 32 cm  but in practice the diagonal is usually shorter than that of a square with a side length of 30 cm.
From my point of view, it would clearly be easiest to allow cones with a base plate of up to 32x32 cm  but if the majority is against this, a reasonable compromise could be that we allow larger base plates (up to 32x32 cm) only on condition of beveled corners and a maximum diagonal length.
To (1): I understand the rulebook in such a way that the base plate must fit into a square with the maximum side length of 30 cm  so that allows in principle also each other form, if it fits into this square.
To (2): I have never thought about this before. The cones with square base plate were indeed always aligned parallel to the main lines at all competitions I remember so far. Maybe we could add a corresponding sentence here.
Comment
I put the video on WeTransfer, the link is https://we.tl/tZVB3S1jZ48 .
Note that this link is only valid for ONE WEEK.
Also, please don't redistribute the link or the file, and use only for Track Rulebook purposes.
(1) I think I would rather prescribe a circle that the base plate must fit into, than a square. (Actually, that such a circle must be between x and y centimeters.) This is mostly because the line that the rider rides around the cones, resembles more a circle than a square, so it's that "outer circle" (circumscribed circle) that really matters.
(2) If we want to accommodate hexagonal cones as well (although they are rare), we could e.g. require that at least two of the edges of the baseplate are perpendicular to the start/finish line. That seems the most sensible orientation for me (that is, the fastest, and also normally used), especially in the row of cones 3 to 7.
If the base plate is circular (which is acceptable to me), there is obviously no orientation requirement.
Comment
I agree with the idea of specifying a diameter, in which the base must fit. This allows for a wider range of cone bases. When competitions are held in new locations/countries, we may encounter compatibility issues, which could lead to needing to either be flexible, or possibly mean shipping sets of cones across oceans. Back in the early days, we were flexible.
Back in the day, we experimented with how to position the cones' bases. At the time, our group concluded that it didn't make a difference anyone noticed when actually riding the course. That video of Mathias, BTW, is fantastic. Surgical precision, and no space wasted around any cone! Small turns shorten the distance ridden, which seems like the obvious approach to take after watching him. :)
The size of cones we use for the IUF Slalom are quite a bit smaller than the typical cones that are used in the USA for highway traffic; that is, when cars are going fast. These smaller cones are more commonly used in relation to parking, or other situations where vehicles are moving more slowly. That might relate to a possible difficulty finding standardized dimensions for this category of cone, as they are perhaps less vital for safety than the larger ones.
If it becomes more complicated/difficult, we could specify some sort of cone that can be handmade out of common materials. The problem with such a cone is that if it's rigid, it won't "bobble" like the types of cones we are accustomed to. But that's one possible approach. I now own a set of four traffic cones for our camping trailer. These are in the size category that we use for the IUF Slalom, but they're retractable; the cone part folds down into the base, with is about 3cm thick. The cone part is fabric, with a series of rigid rings inside, so that part is flexible. Because they are lighter than the typical cones we're used to, their sensitivity to being struck may be different. But they're much lighter than the usual type, meaning they're much easier/cheaper to ship due to their light weight and small size.
I hope some of that ramble was useful...
Comment
At least your first two sentences were :)
I come back to my earlier (2). I'd now say that if the cone base has straight edges, at least one of them must be perpendicular to the start/finish line. Now triangular base plates also fit in the rule. That edit is based on some of John's ramble, which thus also was useful.
Comment
First of all, thank you Klaas for sharing the video. It really shows how a top rider moves through the slalom and how close they come to the cones. If you watch the video, you can see during the slalom in the moments where Mathias is riding towards the camera, how big the distance between the tire and the base plate is  in the other moments the perspective mostly pretends a smaller distance. I would estimate that it is about 5  6 cm and thus so much distance that even with a 32 x 32 cm base plate there would still be about 3 cm space. You can also see that the foot is already slightly touching the cones, which makes them wobble a bit. Getting even closer to the cones would probably not be possible without touching them completely with the foot.
In principle, I agree that it is reasonable to define a circle in which the base plate of the cone must fit in order to ensure maximum flexibility. As the video shows, if the base plate of the cones were circular, this would not be a limitation when riding  but we should keep in mind that this could have a psychological effect that is not negligible. The distances between the cones in the salom would be reduced by almost 20 percent if the base plate were circular with a diameter of 43 cm (which corresponds approximately to the diagonal of the current 30 x 30 cm square). As I said, this would have no effect on the actual riding, since you ride in a circle around the cones anyway, but I don't know how big the psychological effect would be. So I think we should think twice about whether we really want to allow such large circular base plates.
I think it is the same with the orientation of the cones: For the reasons mentioned above, it doesn't really make a difference how the cones are aligned  psychologically, however, it might make a very big difference if cones with a square base plate are placed at a 45° angle to the slalom direction, seemingly making the available space between the cones significantly smaller  even if you could never ride in the "missing" space without knocking the cone over.
Comment
I'd add that the course is not only for the fastest riders, but also for more mundane mortals. They ride more upright, and so for them the size of the base matters not only psychologically, but also physically.
Also, the current rulebook only says that the bases may be no more than 30 cm square. This applies in my mind to how far the sides of a shquarish base are apart. But I'm pretty sure that no actual cone base has sharp 90 degrees corners. They will in practice be rounded and/or beveled to some degree. That means the base would fit in a smaller circle than ~ 43 cm.
Jan, can you find out the diagonal size of your squarish cones? I can find out the diagonal of our hexagons. Anyone else has access to cones used in competition? This would give us some guidance as to the max diameter to allow.
Comment
"I'd add that the course is not only for the fastest riders, but also for more mundane mortals. They ride more upright, and so for them the size of the base matters not only psychologically, but also physically."  I completely agree with you here, but I have already calculated above that even in a perfectly upright position, the pedal/foot will first come into contact with the cone before the tire touches the base plate  even with a 32 x 32 cm base plate. So even these riders will not be able to ride in every visually available space between the cones, or they will bump into the cone. But especially for inexperienced riders the psychological effect could be much bigger, because they probably pay much more attention to the apparent space than the top riders.
Of course the cones never have Perfect 90 degree corners  but the cones used in the video for example have only very very slightly rounded corners, I guess their diagonal is about 41 cm or maybe even a bit longer. So if we go here significantly below the diagonal dimension of the currently allowed 30 x 30 cm square, we will certainly exclude some of the currently allowed cones.
The cones that are used in Germany by many clubs, including me, have a base plate with a diagonal smaller than 40 cm (in the range 37  38 cm)  but this is definitely shorter than for some cones with 30 x 30 cm base plate and significantly less beveled corners.
Comment
Only now I paid closer attention to the cones in the video. Indeed the square seems hardly rounded. I have always assumed that you cannot ride over the cone base, it would be too much of a bump. However, these cones have a thin baseplate, that in itself you could ride over without consequences (apart from the pedal/cone collision issue). Only the smaller circle on the base is nonrideable in itself.
The purpose of specifying a maximum base size, I think, is to prevent having cones which are too stable, to the point that riders hardly need to worry about not hitting them. We could still specify a max diagonal of 43 cm in the rulebook. The usual cones in Germany would fit within that rule. I'm not sure if we also would need to specify a minimum outer circle. What would the purpose be  perhaps to prevent unfair disadvantage by having cones that are not stable enough? Is this something for us to worry about, within the framework of the rulebook? Until now, the Rulebook does not specify a minimum.
Comment
Fast riders come into the center 5 cones on a sharp slant, but are more upright through the rest of them than on the other cones. But watching Mathias, he seemed much more upright than one would expect, especially from someone of his height! But none of that really matters; it's really all about missing the cones.
Klaas brought up the very important point of cone stability. Different materials and different thicknesses affect how much force is required to knock over a cone. I don't think we want to legislate this; it would probably lead us to requiring only a very specific type of cone, that would only be available to people in certain parts of the world to practice on. Weight is also a factor. But we've managed to get by for 20 Unicons now, using various cones from around the world and nobody seemed too upset. I think at Unicon X in China we had much larger cones than we expected; I'm not in a place where I can look up old photos. None in my online Smugmug gallery of Unicon X :( But in the end, they were the same cones for every rider, and we got by. But we should be able to have reasonable expectations of what the cones will be. I suppose in the worst case scenario, a host can say "This is the closest thing we have, and these are the dimensions" so people can be prepared ahead of time. But this is not what we hope to have to do.
As for base size, I can't remember ever running over the edge of a cone base while practicing this event. It doesn't seem to be an issue for cones that are proportionally similar to what we use. We should look for examples with large bases, and if those bases are square, measure from corner to corner to build up a list of what's out there. My collapsible cones measure about 33.5cm corner to corner, as if they were not rounded. Actual measurement is 32 or less. They have a narrower base than typical, heavier cones.
I am in favor of using a measurement that represents a diameter, or diagonal measurement, to allow for any base shape. increasing the size by a small amount is not likely to affect most riders.
Comment
In my experience, for the stability of the cones, the weight of the base plate is indeed much more crucial than the size  especially when it comes to the difference between, for example, a 25 x 25 cm or a 32 x 32 cm base plate with beveled corners. With a 5 x 5 cm base plate it would perhaps be different, but since we have a height specification for the cones in the rules, I don't think commercially available cones will ever have a base plate this small. So I think the specification of the size of the base plate is really mainly about the space supposedly available for the riders. And for that reason, and the explanations above, I would rather stick with the specification of a square base plate.
I think we agree in principle that we would allow the European standardized cones with a square base plate (and as far as I know always beveled corners, but the standard does not mention this) and a maximum base plate of 32 x 32 cm. The question that is not really clarified yet is how we define the dimensions. There are several options:

The base plate must fit into a circle with a diameter of 43 cm.
Note: I would not prefer this option for the reasons mentioned in the discussion. 
The base plate must fit into a square with side length 32 cm.
Note: This would certainly be the simplest rule, but it would theoretically make the diagonal about 45.25 cm long. 
The base plate must fit into a square with a side length of 30 cm. Square baseplates with larger side lengths are also allowed, as long as the diagonal does not exceed 43 cm.
Note: This would be a compromise of the current rule and the fact that it would include the cones according to the European standard.Or were there other suggestions that I overlooked?
Comment
The current rule (2B.8.1) does not clearly specify a square base plate. It merely says "with bases no more than 30 cm square". You can read this as "with bases of any shape that fits within a square of 30 x 30 cm".
A square base not being required, I would still prefer "must fit within a circle with a diameter of 43 cm". This rule is IMO as simple as "must fit within a square with side length of 32 cm".
While my preferred rule does allow circular baseplates that are so big that they seem to be an obstruction (even while they are not really an obstruction), we will mostly see square baseplates, because they are the most readily available. In other words: in practice not much changes. And even if a course would be set up with large circular bases, it would be the same for all competitors.
Comment
Yes, of course, and that's how I've always read this rule so far  the base plate must fit into a square with a side length of 30 cm, no matter what shape it has exactly. But that's also how I would understand all three proposed options.
I agree with you that the rule option 1 is just as simple as option 2.
What we haven't even considered yet in terms of allowing circular base plates is the following: For the rider and the possible space for riding, the option circular base plate with 43 cm diameter and square base plate with 30 x 30/32 x 32 cm is only identical (excluding the psychological effect) if the cone (i.e. the body) itself does not become wider. The requirement that the base plate must fit into a square also automatically ensures that the cone body does not become wider at the base than the side length of the square. If we now allow circular base plates, then the width of the cone body at the base could also increase, theoretically to 43 cm  and this would then actually reduce the usable space.
Comment
I also hadn't considered your additional thought. That makes options 2 and 3 better.
Option 2 is simpler but may result in quite large cones.
Option 3 is maybe better, but taken literally it doesn't make sense. A square with side length of 30 cm mathematically has a diagonal of 42.4 (rounded to 1 mm). So it cannot exceed 43 cm anyway.
How about:
The baseplate must be square or hexagonal, possibly with rounded or bevelled corners. It must fit within a 43 cm circle.
Comment
What you left out of option 3 is that before specifying the diagonal it says "Square baseplates with larger side lengths are also allowed, [...]". Otherwise I would agree with you, with a square of 30 x 30 cm the diagonal can never be longer than 43 cm. In principle, I would also agree with your suggestion, but this would actually eliminate cones with round base plates completely (I don't know how common they are, but they definitely exist).
Comment
Another suggestion to improve option 3:
The base plate must fit into a square with a side length of 30 cm. Square base plates with larger side lengths are also permitted, as long as they have rounded or beveled corners and the diagonal does not exceed 43 cm.
Comment
Your suggestion has the advantage that it allows circular (or really, any shape) baseplates as long as they are sufficiently small, so as not to obstruct the rider more than the usual cones with squarish base that the circular cone fits within.
But it raises a question of definition: What is the side length of a square with rounded corners? Is it the straight part only, or is it the distance between two opposing sides? Or maybe 25% of the circumference, measured along the rounded corners?
My suggestion does not depend on this definition. The disadvantage is that only square and hexagonal base plates are allowed. But I don't think this is a problem in practice.
Comment
We must assume the possibility of round baseplates (if only to save ourselves from redoing this in a few years). Our dimensions can start with a maximum edge for square bases, but should then follow with a diameter just in case. "diagonal" works for square bases, but not for hexagons or other shapes. The other key dimension is probably the base diameter of the cone part. The third would be height, which is less important unless the cone is very tall. Perhaps the best way to remain flexible in a world where we may encounter unusual cones, is to offer maximum sizes for the following:
 Base length (square)
 Base diameter (other shapes)
 Diameter of bottom of cone
 Overall height of cone
At the risk of making assumptions of unknown international cones, I think we only need to worry about maximum sizes for all of those except height. We don't want the cones to be too small. But as long as a cone is tall enough, the other dimensions should only need to be maximums. Once we settle on those numbers, the key point is to allow for "a conversation" if a country has something that's close, but larger (or smaller) than what we want.
I offer an example: (using suggested numbers; available for changing). I do not have easy access to a full Rulebook to reference; limited Internet here at Morro Strand State Park (Morro Bay, California):
 Square base, max. 30 cm wide
 Nonsquare base, fits max. 43 cm diameter
 Bottom of cone part, xx cm diameter
 Cone height, minimum xx cm high, and max. yy cm high
If cones fitting these requirements are not available in the host country/region, competition organizers must share photos and dimensions of cones that are available to decide if those cones can be used. This will enable all participants to be prepared for unusually sized cones.
Optionally, it's probably possible to make cones to IUF spec., but the challenge with that will be making them behave similar to typical traffic cones when struck by pedals. There would need to be a good mix of weight and flexibility for them not fall too easily or be too stable. Something to consider for the future if traffic cones evolve away from what we're used to... :)
Comment
Okay, I realize that the definition according to option 3 is less clear than I had thought. For me, the side length of a square with rounded edges was obviously the distance between the two opposite parallel outer edges.
I would agree with John, however, that we should assume that somewhere in the world round baseplates are also used that comply with the current rules and for which there is (from my point of view) no reason not to allow them in the future. At the same time, I would like to keep the rules as simple as possible and not define additional dimensions like the diameter at the bottom of the cone body.
Regarding the height requirement: We already have that in the rules (between 45 cm and 60 cm).
What speaks against option two?  The base plate must fit into a square with side length 32 cm.
This preserves the flexibility regarding the shape of the base plate and at the same time prevents that round cones with a significantly larger base diameter could be used (as it would be the case with option 1).
Comment
I have no problem with a somewhat more complicated set of rules for the cone dimensions, along the lines of John's suggestion. After all, the riders don't have to worry about this, it is only a onetime concern for the organisers to decide which cones to use.
What speaks against "The base plate must fit into a square with side length 32 cm" is that it would disallow some good cones. I just found out that the "Dutch" hexagonal cones do comply, but if they were a bit larger they would not comply with that rule, but still with John's set of rules, and also with my "feeling" of what is right.
Indeed, the height is already regulated as between 45 and 60 cm  let's keep that.
The dimension that John put to Square base, that is 30 cm wide, also corresponds to the current rule ("with bases no more than 30 cm square").
For the bottom of the cone, I would suggest a maximum of 30 cm diameter. That is the largest cone that could fit on a square base plate of 30 x 30 cm.
Comment
But which cones would the rule "The base plate must fit into a square with side length 32 cm" prohibit? Currently, all cones have to fit into a square with a side length of 30 cm  so the rule would definitely allow more cones than the current one. And apart from the cones according to the European standard, I don't know of any common cones that are not covered by the current rule. Of course, if there are some, that's a valid argument, I agree.
All in all, I am still skeptical about allowing cones with a round base plate and a diameter of 43 cm, as this would significantly reduce the supposed available space between the cones in the slalom and I fear that this would definitely have a psychological effect to the riders.
Comment
You wrote: But which cones would the rule "The base plate must fit into a square with side length 32 cm" prohibit?
A hexagonal base plate with sides that are 30 cm apart has a diagonal of 34.64 cm. I think this would be a suitable cone, but it would not fit. As I wrote, the currently used cones at the Dutch nationals are smaller and they do fit, even in a 30cm x 30 cm square.
You wrote: All in all, I am still skeptical about allowing cones with a round base plate and a diameter of 43 cm, as this would significantly reduce the supposed available space between the cones in the slalom and I fear that this would definitely have a psychological effect to the riders.
You have a point there. Maybe 43 cm is too much. What about 35 cm instead? Then the (hypothetical) hexagonal cone with sides that are 30 cm apart would fit.
What I like about John's set of rules, as compared to your suggestion, is that it maintains the 30 cm that is currently in the rules. At the same time, it gives additional rules so as to facilitate the use of various cone types around the world, while limiting the variation in terms of "difficulty" for the slalom.
Comment
To 1: Okay  but are these also cones that are available? Or are the available cones anyway the ones that are used on the Dutch nationals and therefore can already be used according to the current rulebook?
To 2: What I think is difficult about John's definition are the following things:
1. Square baseplates with a side length of 30 cm  Okay this is according to the current rule, everything is fine.
BUT: What counts as a square base plate? All cones I know have at least slightly rounded corners! Cones that have a perfect square as a base plate will probably not exist. Does this mean that all cones fall under point 2?
2. If all cones fall under the point "Nonsquare base", then we cannot choose a radius smaller than 43 cm, because otherwise even currently approved cones with a 30 cm x 30 cm base plate and rounded corners would no longer fit. If we leave the radius at 43 cm, what I described above comes into effect.
3. The diameter of the lower part of the cone body is difficult to measure (compared to the size of the base plate). Often the cone body itself is somewhat rounded at the bottom  so at which point exactly should you measure? Where the rounding starts? Where it ends?
My cones have a diameter of the cone body of about 18 cm to 23 cm  depending on where you measure. I think 30 cm would be very wide here, because the base plate is always at least a little larger than the cone body so right now 30 cm cone bodys will never be the case.
So I am still in favor of defining the permissible cones by the size of the base plate and the height. If we do not want to exclude the cones with hexagonal base plate mentioned by Klaas, we could also formulate the whole thing as given below, even if the wording is a bit more bulky than my original proposal 3.
All cones are allowed which have a base plate that fits into a square with a side length of 30 cm or which have two opposite parallel sides that are not more than 32 cm apart and which fit into a circle with a radius of 43 cm.
Comment
To 1: I don't know if such cones exist. The "Dutch cones" can indeed be used with the current rulebook. One reason John mentioned why he came up with his set of rules is to "remain flexible in a world where we may encounter unusual cones".
To 2:
1. Indeed, the cones that are colloquially called square, are not exactly square. To be more mathematically accurate, you could write "square base, possibly with rounded or bevelled corners"
2. Not applicable.
3. True. Realworld objects are not mathamatical bodies. It's the same with the rounded corners, which changes a square into something that is not a square. I think what I had in mind, assuming cones of which the largest part along their height is straight, is the circle where the (extended/elongated) cone intersects with the surface on which the cone is standing. But this is not rulebook language, it is not really feasible to be mathematically precise for some requirements including this one.
In your italic text,
(a) Do we need "and which fit into a circle with a diameter of 43 cm"? This only comes into play if the base plate is not a polygon (e.g a trapezoid), I think, but is this realistic? (Note that I changed radius to diameter, I think that's what you meant);
(b) a circular baseplate of 33 cm diameter does not fit in this rule, but seems adequate to me.
Comment
To 1:
I think it's very hard to draw the line on the acceptable size with a hypothetical cone. I would say a cone with a hexagonal base plate and sides that are 32 cm apart could also be suitable, or one with 33 cm, or with 33.5 cm  if we knew that there were some with 33 cm, it would be easier for me to say: Okay, we still allow them. But without knowing a specific cone, I tend to say that we should make the base plate as large as necessary, but as small as possible. And currently it is the 32 cm x 32 cm cones, according to the European standard, which are not covered by the current rules.
To 2:
1. If we change it here to "square base, possibly with rounded or bevelled corners", the 32 cm x 32 cm cones according to the European standard are still not suitable. Because I would also describe this base plate as "square base with bevelled corners" and the cones would therefore fall under this description.
3. I think we have to keep in mind that the specifications have to be verifiable for the organizers. And measurements that are very difficult or impossible to check on a real cone are therefore unsuitable.
Regarding my text:
(a) I used the circle, because it is very easy to check if a base plate fits in there. If we would assume that the bottom plate is a regular polygon, we get a problem with the definition again for rounded or beveled corners  see discussion above.
(b) That is correct  here again exactly what I wrote above under "To 1:" applies.
Comment
>I think it's very hard to draw the line on the acceptable size with a hypothetical cone.
But that is exactly where I come from! We don't know what types and sizes of cones exist in the whole wide world. Oh well, we know some of them, and if we think they are adequate for the slalom, then our rules should be such that they allow them. But for all the other "hypothetical" cones we need to draw lines (what is allowed and what is not) without knowing those cones. In other words, the departure point for making rules is what we consider acceptable, not what cones exist (and we happen to know).
I would appreciate if others chime in as well!
Comment
Of course, the starting point for setting rules should be what we think is acceptable, not what cones are available. But when it comes to the question of what we consider acceptable, we have to weigh the balance between "larger base plate = more flexibility and more possible cones" and "more restrictions for the riders (even if it's only psychological due to seemingly less space". And in this consideration I would always go in the direction of "as small as possible, but as large as necessary". And then the available cones come into the equation again.
One could also argue that the 30 cm x 30 cm are the maximum acceptable and were therefore determined in this way. However, if this means that a readily available type of cone, which has been used by some clubs for years, is eliminated, I think we should consider changing the maximum acceptable size so that the cones that are already in use become permissible.
Comment
Above I made an attempt at a set of "dimension limits", but it's missing dimensions for cone diameter at bottom and overall height. I guess we need to agree on a set of limits to use, and that these should work with known cones that people are successfully using, or have used, for Slalom competition. From there, the section that talks about cone size and composition must have instructions of what to do if a competition host only has access to something that doesn't fit. A process for them to communicate measurements (and pictures?) of what they have, and to have it approved. If not approved, that means someone will import multiple sets of cones of acceptable dimensions to use in that competition. They would need a minimum of 20 cones, plus spares.
How about an extra 2 cm for the base:
 For square bases, max. 30 cm wide
 For nonsquare bases, fits max. 43 cm diameter
 Bottom of cone part maximum xx cm diameter
 Cone height from ground, minimum xx cm, and max. yy cm
If we can lock down those numbers, then we just need to write some text for the hypothetical situation of future cones that aren't a close fit.
Comment
I think the short commings of this set of "Dimension Limitis" we have already discussed in the last days (see especially my comment from three days ago).
I am still convinced that a base plate with a diameter of 43 cm is too big, even if we limit the diameter of the cone body at the bottom. We should not make the distance between the cones in the slalom smaller than absolutely necessary!
So I think the question should be, what is the maximum size of a round base plate without making the distance between the cones too small? You know my opinion "as small as possible, as big as necessary" (i.e. 32cm).
For all nonround baseplates you could say that they have to be regular polygons (with round or beveled corners) and must not exceed a height of X cm. (Where X cm then corresponds to the maximum diameter of a round base plate in our opinion).
Of course, we can also add a sentence to the rules on how to proceed if only cones are available that do not comply with these rules and how they can be approved by the IUF.
1. All cones are allowed
1.2 whose base plate is a circle whose diameter does not exceed X cm, or whose base plate is a regular polygon (with rounded or chamfered corners) whose height does not exceed X cm, and
2.2 that are between 45 and 60 cm tall.
Comment
I don't think 43 cm is too big, but I will agree to a smaller size that you recommend. I tried again to find a picture of Chinese traffic cones with round bases. Looks like I took zero photos of the Obstacle Course at Unicon X, but I did find a picture of highway cones with round bases:
https://www.dropbox.com/s/os5d67y2za7dtzu/20000812_136_foss.jpg?dl=0
This is the USA Team (along with everyone else) riding from the hotel to the subway, to ride into downtown Beijing and do a "demonstration" in Tiananmen Square. The cones in that photo may be the same type that were used for the Obstacle Course. They're larger than our typical ones, but seemed to work out just fine for Unicon X. I don't remember complaints. Unfortunately the results aren't published anywhere. I have some crappy printouts of the results from the computer. Winning time (male) was 21.06, which is slow by today's standards, but not bad for those days. Those Chinese cones were tall and wide, but the bases didn't stick out much. I would guess they are less than 43 cm.
Next question is how big can the bottom of the cone part be? We should add on a bit to some existing cones people can measure. That is a more important dimension than the base, as it's closer to where pedals may knock down a cone. I don't have a reference cone handy; my collapsible ones are smaller than Slalom cones.
Comment
I agree with Jan that for circular baseplates, a 43 cm circle that the baseplate must fit in, is too large. Even if for faster riders the disadvantage would be only psychological. Slower riders may have a physical disadvantage due to their more upright position, if you see what I mean.
I think I also agree to "as small as possible, as big as necessary". Initially I thought that a too small baseplate would make the cone topple over too easily, at the disadvantage of the rider. But now I think this would be compensated by a smaller chance to hit the cone in the first place.
Comment
"As small as possible, as big as necessary"? Does that apply to noncompliant cones? As a general rule it would lead to very tiny cones. :)
What we haven't covered (and probably can't do much about) is the stability of cones. This would be very hard to define, as it's a combination of weight, material, and the flexibility of that material. So I think we need to stay away from it. Cones should be stable enough to not move or fall over in a strong wind. Beyond that, it's about not touching them. Some will be more stable than others.
We should try to stay close to the "typical" proportions of the traffic cones we are familiar with, while having a "pressure release valve" when a host doesn't have anything that fits.
Comment
I think the "As small as possible, as big as necessary" should apply especially to our considerations, which limit we write into the rulebook. Since the European standard allows cones to have a baseplate with a maximum of 31.8 cm x 31.8 cm, my suggestion would be to write 32 cm into the rulebook  just as a measurement that would be necessary to allow these cones, which are already used by many clubs, and at the same time remain as small as possible.
But I also see Klaas' argument that cones with a hexagonal base plate, where the parallel sides are 32 cm apart, would be just as suitable. That's why I had made an alternative suggestion to "into a square with side length 32 cm".
Regarding stability, I agree with John that many other factors have an influence. But I don't think we can cover them all. A maximum weight would perhaps be the only thing that would be realistic to include in the rulebook. We could also write that traffic cones are usually used, which automatically have to have a certain stability, otherwise they could not be used in traffic.
I think basically we need to clarify the following questions:
1. What is the maximum size of the baseplate or the minimum distance between the cones in the slalom that is acceptable for us?
(My opinion: 32 cm baseplate or 68cm gap between the cones in the slalom).
2. Do we want to stay with the simple rule that the baseplate must fit into a square of the appropriate size or do we want to change the rule so that, for example, in the case of a hexagonal baseplate, only the parallel sides may not exceed the appropriate distance?
(My opinion: for me it is OK if we make the rule a bit more complex; see my last suggestion).
3. Do we want to include something about stability?
(My opinion: rather not, at most a maximum weight; if we should rather refer to the fact that usual traffic cones are taken)
4. Do we want to include something about how organizers can have deviating cones approved by the IUF?
(My opinion: deviations from the IUF rules can be approved by the IUF anyway according to 1A.1.2 Other Uses for These Rules, so I wouldn't mention it here again explicitly).
Comment
>"As small as possible, as big as necessary"? Does that apply to noncompliant cones? As a general rule it would lead to very tiny cones. :)
Jan intended this as a guideline to make rules, not to literally include in the rules. But even if it were included, it would go together with the height requirement of between 45 and 60 cm. Very tiny cones are thus out of the question.
>But I also see Klaas' argument that cones with a hexagonal base plate, where the parallel sides are 32 cm apart, would be just as suitable. That's why I had made an alternative suggestion to "into a square with side length 32 cm".
Note that a hexagon with sides 32 cm apart doesn't fit in a square of 32 x 32 cm. The diagonal (longest line in the base) is approx 34.64 cm.
My responses to the post above:
1. and 2. I can live with a general rule that the baseplate must fit in a square of 32 x 32 cm (also because of 4.).
3. I agree that mentioning traffic cones is sufficient for stability requirements.
4. I agree that deviations from any rule can be discussed with IUF and possibly approved by them, and so there's no need to add something to that effect here.
My remaining question: do we need to specify anything about the dimensions, notably the width/diameter, of the actual conical part? Maybe not, if only because it is difficult to phrase a rule that can actually be measured/checked. (like: at what height? how to handle rounded transitions between baseplate and cone? what about the top diameter, as a cone usually is truncated?). So maybe for diameter we should just rely on the general relative sizing of traffic cones. Frankly, we've been doing this for years.
Comment
> Note that a hexagon with sides 32 cm apart doesn't fit in a square of 32 x 32 cm.
Of course  that's why I suggested the alternative definition with the height of a regular polygon ([...] whose base plate is a circle whose diameter does not exceed X cm, or whose base plate is a regular polygon (with rounded or chamfered corners) whose height does not exceed X cm [...]). Exactly this was the aim of question 2. The old definition with the square is of course the easiest to understand and the easiest to verify  so if everyone can live with it, I would prefer to stay with this definition.
> do we need to specify anything about the dimensions, notably the width/diameter, of the actual conical part?
I would be in favor of relying on the general relative sizing of traffic cones here. I think the dimensions are difficult to define for the reasons mentioned and if we only slightly increase the permissible dimensions of the base plate, I think the traffic cones that are possible as a result do not have a significantly larger cone body than those that have been permissible for years with the current rule.
Comment
I think we are getting to where we have a pretty good understanding of the size/type of cones we want, so we are now trying to define in noncomplicated ways. For bases, maybe we need an alternative measurement for nonsquare ones. One max. width for square bases, a slightly bigger one for bases with more sides, and possibly a third in the (rare) event of circular bases. Or maybe keep it more simple, with the example only for square bases, and if nonsquare bases are the closest thing available, a discussion with the IUF on size. Same for height, keeping our existing minimum and maximum numbers.
That covers size. The other thing to cover might just be something on stability. We can't define that without getting into a long, wordy text, so probably have something to the effect that there should be some tangible weight to the cones (similar to the traffic cones we traditionally use, whatever that is), and possibly a statement that if they won't stay put in a stiff wind, they may be too light/unstable. In fact, cones that can be moved by a strong wind on a windy day, and therefore too light. You can't tape them down of course, but I suppose hosts could add some weight to them to make them stay put.
Comment
It looks to me like we can agree to stay in general with the existing simple definition and just increase the base plate dimension from 30 cm to 32 cm?
I like the idea about adding a note regarding the wind  see my proposal.
Note: I would like to revise the rule for the slalom as a whole and adapt it to the style of the other rules that we have already revised or for which there are already proposals. For this I would start a new discussion to separate the voting from the dimensions of the cones.
Old rule:
[...]
The cones used are plastic traffic cones. For official competition, cones must be between 45 and 60 cm tall, with bases no more than 30 cm square.
[...]
New rule:
[...]
The cones used are plastic traffic cones. Cones must be between 45 and 60 cm tall and the base plate must fit into a square with side length 32 cm.
Note: The cones should be stable enough to stay put even in a stiff wind.
[...]
Comment
I'm fine with that new rule.
Native speaker, please advise, is it "fit into" or "fit in"? I'm guessing the latter.
Comment
For the proposed text above, note the errant space in "tra ffic". Also the word plastic is a bit limiting. The traffic cones we use the most in the USA are of a rubbery, flexible material that probably has "poly" in its name, but is closer to rubber than plastic. How about using "plastic or similar material". In the second sentence, consider adding "and heavy" after "stable". Lastly, it may need an additional sentence to cover nonsquare bases, such as: For cones with nonsquare bases, share their dimensions and shape with the IUF Rules Committee to determine if they comply.
Rather than trying to anticipate any nonsquare shape/size, we will let the world come to us, and determine if they will work, and possibly add that information to future versions of this rule.
Comment
>note the errant space in "tra ffic".
I don't see that errant space on my screen (laptop, Win10, Firefox)
>How about using "plastic or similar material".
Yes to that.
>consider adding "and heavy" after "stable"
Not needed, in my opinion. I don't care if the cones would be light, as long as they are stable enough to stay punt even in a stiff wind. They probably would need to have some weight to them to achieve that, but it's not a goal in itself.
>it may need an additional sentence to cover nonsquare bases, such as: For cones with nonsquare bases, share their dimensions and shape with the IUF Rules Committee to determine if they comply.
Nonsquare bases are covered, I think. Any shape, provided it is small enough, can fit in a 32 x 32 cm square. Only if they wouldn't fit within that, IUF judgement is called for. BTW, the Rules committee is not a permanent committee, I think?
>Rather than trying to anticipate any nonsquare shape/size, we will let the world come to us, and determine if they will work, and possibly add that information to future versions of this rule.
Amen to that.
Comment
I've copied the text with the space below:
[...]
The cones used are plastic traffic cones.
Definitely a space; I can select it also. Strange that it's not showing for you.
I agree about "and heavy"; long as it's stable and won't blow away, hopefully that's enough. In the past we have used relatively floppy cones, as well as stiff plastic cones. I don't think there's a good way to describe in words/rules how "stable or unstable" they should be.
If nonsquare bases are implicitly covered in our existing text, that should be fine. Anything outside the (now simpler) parameters requires sharing of cones with the IUF so we can go from there. And also, build up our "International Database of Traffic Cones for Slalom!"
Comment
> Nonsquare bases are covered, I think. Any shape, provided it is small enough, can fit in a 32 x 32 cm square.
This is what the rule proposal is supposed to say  if this is not clear enough, we should adjust the wording. For me, it is clear even with the current wording.
> >Rather than trying to anticipate any nonsquare shape/size, we will let the world come to us, and determine if they will work, and possibly add that information to future versions of this rule.
Amen to that.
I think we had already said that "1A.1.2 Other Uses for These Rules" sufficiently covers this aspect, or should we add another sentence or note to the IUF Slalom rule?
I added "or similar material" and looked for the space in "traffic"  but I didn't see it either. I just retyped the whole word again. I also changed "fit into" to "fit in"
Proposal:
[...]
The cones used are plastic or similar material traffic cones. Cones must be between 45 and 60 cm tall and the base plate must fit in a square with side length 32 cm.
Note: The cones should be stable enough to stay put even in a stiff wind.
[...]
Comment
Great.