Costing - changing the difinition of the measuring point (change 3B.6.2)
This discussion has an associated proposal. View Proposal Details here.Comments about this discussion:
Started
Coasting rule 3B.6.2 contains various points which are decisive for determining the wheel position. I think we should unify this.
Extract of the two relevant sentences from Rule 3B.6.2:
1. The distance is measured [...] to the rear of the tire where the rider stops coasting.
2. If a rider crosses the coasting line (front of the tire) [...].
I know that for the moment of the start and the finish at the track races, the fronts of the tires is decisive - this also makes sense for the electronic aids used there. During the coasting, however, the moment where the rider stops coasting and the crossing of the coasting line are judged by judges for whom it's much easier to observe the tire contact point. For this reason, I think that the tire contact point is the decisive point when judging the 5 m line at the one foot race for example.
Therefore I would suggest to make the tire contact point the decisive point during the coasting event for the two mentioned sentences from Rule 3B.6.2.
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I agree.
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The front or the back of the tire contact point? It is not actually a point but instead a patch of ground.
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I haven't heard this question before. If I judge Slow Race (which I don't like to do BTW), I use the centre of the contact patch, eyeballing where that is. The contact patch may not be constant in size (especially in coasting because of the way that riders maintain balance), so the front and back of it move 'erratically', but the centre of it should move relatively smoothly.
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That sounds like it could be defined as the point directly below the center of the axle.
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That is a precise definition, and in that sense better than centre of contact patch because the contact patch itself is not well-defined. And it is consistent with what I mean.
However, in practice most people would still judge by the contact patch, not by imagining some line straight down from the centre of the axle.
Comment
Scott's right, of course, that there won't be a single contact point. But so far I have honestly never thought about it and always understood the tire contact point as the point described by Klaas. Since the tire contact point is also mentioned in other sections of the rulebook, it would perhaps be useful to define it once (for example, in chapter 1D.1 Definitions?) in order not to have to insert a definition in all other sections.
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I agree with Jan. I do think it's okay to use the center of the contact patch as the definition. Or the center of the axle. The second option is more fixed (and thus precise in that manner) but has to be judged with an eye downwards, which loses that precision.
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I take back that Scott's definition is consistent with what I mean.
If the wheel is angled away from the centre line of the race track (e.g. in Slow race this is allowed up to 45 degrees), AND if the unicycle leans sideways (which in Slow race and probably also in the last few meters of coasting is quite common), then the two definitions suggested above don't indicate the same point. In other words, we have to choose one, not both.
I think that even if "centre of the contact patch" is mathematically less precisely defined, in practice this is a better definition.
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The contact patch is what you can see. Unless we can imagine a way for riders to advantage themselves at the end of a Coast by wildly contorting their body, center of contact patch should work.
Actually, while not being an expert at long distance coasting, I imagine the way to achieve the above would be to fold your body down while pushing the wheel forward. Which is fine. While Klaas' example above is true, I don't imagine it being a factor in the top riders, though it could affect age groups or something. I'm trying to imagine a rider attempting to maximize distance by maximizing a curve, but I don't think it would be helpful. Your coasting distance should be measured in a line that follows the track, not the path of your riding.
So, for example, if someone makes a sharp turn at the end of their coast, whatever measurement we take should be perpendicular to the rider's main direction of travel along the track. any curving would effectively shorten that distance, and not be advantageous. But yes, how to measure this? perhaps by carrying forward the basic idea of the contact patch, and moving it up to the exact center of the wheel. That would be the centerpoint of the axle, between the two flanges. A spot on the ground directly beneath that.
But for all intents and purposes, without any wild motions by the rider, this should basically correlate to the center of the contact patch, which is easier to see as they go down the track. I guess that would translate out to "We are measuring the location of the center of the unicycle's axle at the moment of dismount. If the unicycle is tilted to the side, mark the spot directly below that. If the unicycle is going straight, the location of the center of the tire's contact patch can be used." Something like that.
Comment
I think we should not refer to the centre of the axle at all, and only to the centre of the contact patch. As John says: that is what a judge can see.
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It seems as if we agree that it makes sense to unify the current two different "measuring points" in coasting and to adapt them to what the judges can judge well. Since there is also talk about the "tire contact point" in other parts of the rulebook, I think it is consistent to use this term also for coasting.
Nevertheless, a suitable definition of this point is currently missing, but as Klaas has already written in another discussion, I think it makes sense to open a separate topic for this discussion. Since the term "tire contact point" is used elsewhere in the Rulebook, I think the Main Committee is an appropriate place to discuss the definition of this term. Then we can leave this discussion with its original topic.
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I started that discussion in the Main Committee. I think even non-members of the Main Committee can follow the discussion, be it without names of the commenters.
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Looks like I'm not on the Main committee either. I asked to be, as some of my ideas cross the boundaries between our sections (mostly to do with racing, keeping similar concepts linked between sub-disciplines, like Road, Track and Muni.
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In regards to contact point/patch: For a unicycle that isn't leaning into a turn, the center of that patch represents the location of the axle on the ground. I think this is true regardless of speed, fore/aft angle, acceleration or braking force. So it best represent measuring the center of the wheel. For purposes of Coasting competition, even if the rider makes a wild turn at the end (with a tilting turn), I recommend we have a standard for that sort of finish, because it can move the contact point farther forward (if done well, anyway). Is this worrying about? Not at the Expert level, I would think, where riders maintain their coast until they run out of momentum. But for less-skilled riders in other categories, it might be seen as a way to "squeeze" out a bit more distance. If we think it's worth adding, I'd say in such cases (of noticeable side angle while turning) we measure from the center of the axle.
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As I have argued, it is more difficult to judge the distance based on the centre of the axle, than based on the contact point. It becomes even more complicated if we normally judge the contact point, but under certain circumstances this moves to the centre of the axle. Even if only for this reason, I am not in favour of this.
Most if not all ways of moving the contact point "artifically" forward, will make it more difficult to transfer to pedaling or wheelwalking. Note that if the rider dismounts, the achieved distance is not based on the tyre contact point, but on the rearmost part of the rider touching the ground. For this reason I am not afraid of the cheating possibilities if we always judge based on tyre contact point.
And then again: this possible "squeezing" out a little bit of extra distance, even though it yields only a slight advantage, can be seen as part of the skill. The same way that experienced sprinters bend forward on the finish line to bring their wheel slightly forwards. Or even running athletes bending their chest forward on the finish line. No one considers this cheating, right?
Comment
Being that the back of the foot is measured in the event of a dismount, I don't consider the small possibility of this to be worth adding rules for. If someone does manage to do it, more power to them, at which point we re-visit this idea and decide if we still like it... :-)
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I like the discussion because I personally have never thought about the possibilities mentioned here - it gives new food for thought.
But I'd say that the very good coasters would coast until they lose momentum and then try to leave the unicycle with their feet as far forward as possible - which is certainly a greater gain in width than moving the tire contact point forward in any way. Even the riders who do not manage to coast until they have no more momentum usually jump forward from the unicycle or "fall" to the ground - in both cases the foot would be the decisive measuring point. In my experience, drivers almost stop coasting without touching the ground with their feet when they touch the tire while coasting, i.e. when they glide. And in this case the wheel is usually upright and the axle is in the middle above the tire contact point.
All in all, I don't want to say that it is not possible to move the tire contact point a little bit forward by a certain technique, but I think in general this will not bring any advantage over the other techniques to end the coasting, because jumping of the unicycle forwards will give you for sure a greater gain in width. So I don't think it is worth introducing an extra rule for it.
Comment
Since there was no further input at this point, I think we can adjust the description. I would change the two sentences mentioned in the firts post as follows:
1. The distance is measured [...], or to the tire contact point where the rider stops coasting.
2. If a rider crosses the coasting line (tire contact point) [...].
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I agree.
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This is a simple and good proposal.