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Vuelta stage 3
 

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LeeW
Joined: 13 Jan 2004
Posts: 453
Location: near Baltimore, MD

8/22/17 6:13 AM

Vuelta stage 3

So I watched the last 30K or so of stage 3 yesterday. I must say it was very entertaining bike racing (over the last 30 km anyway).

Anyway, the winner crossed the finish line with a small gap over the 2nd & 3rd riders. Bob Roll announced the gap as 2 bike lengths. However, I see the official results gave the first 9 riders the same time. I would have "guessed" it would have to have been at at least 1 second separating 1st from 2nd.

Does anyone here know how the UCI determines time gaps? I searched online for rules, but did not find much. Do they go back and look at video footage using a reference clock to measure the gaps, or isn't it that detailed?

Lee

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daddy-o
Joined: 12 Apr 2004
Posts: 3307
Location: Springfield

8/22/17 7:36 AM

No one knows.

http://www.uci.ch/mm/Document/News/Rulesandregulation/18/23/94/2-ROA-20170701-E_English.pdf 2.3.040 page 38

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henoch
Joined: 12 Jan 2004
Posts: 1690

8/22/17 7:46 AM

Going back to the Tour of Utah, I can't recall what stage it was, but it was the one that Bookwalter won, and he clearly had 2 bike lengths over 2nd place, and I was sure and I mean SURE, that there was a time gap and they gave 3-4 other riders same time, I was very surprised.

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

8/22/17 7:55 AM

Two bike lengths is nothing

At 25mph, two bike lengths (~10') would take less than 1/3 of a second, so even though the Stage 3 sprint was relatively slow compared to a typical flat "sprinter's" stage, there was no way that the gap was sufficient to warrant a time difference.

While the decision about whether a sufficient gap exists is at best inconsistent, my understanding is that the difference has to be at least a full second or more, which would translate to 7-13 bike lengths for the speed range of 25 - 45mph.

Here's an mph-fps calculator, if you want to play with the numbers:
https://www.google.com/search?q=converting+miles+per+hour+to+feet+per+second&ie=utf-8&oe=utf-8

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LeeW
Joined: 13 Jan 2004
Posts: 453
Location: near Baltimore, MD

8/22/17 8:18 AM

Interesting

Thanks Daddy-o. Actually the next rule (2.3.041) was very illuminating and points out Brian is right.

2.3.041 All times recorded by the timekeeper-commissaires shall be rounded down to the nearest second.

Note that the rule specified "rounded down". According to that text, any gap up to 0.99 would be rounded to 0 (same time).

I don't think that rule is enforced consistently in the races I watch.
12-13 bike lengths in a sprint finish would seem like a huge gap and I swear I have seen time differences in such a finish awarded for a lot less of a a gap than that

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

8/22/17 8:32 AM

It's hard to judge gaps at speed

The bigger the gap, the harder it is to judge the size, too. In typical sprints where the initial view is from behind the finish line and is shot with a really long lens, it always appears that the bunch is really tight. Finish line cameras also shorten the apparent gaps. Unless you have an overhead view, it's hard to tell what the gaps really are.

I've seen a lot of races where the peloton is really strung out in the final sprint, but as long as there aren't any big gaps, everybody gets the same time, even though they may be crossing the line 5 or more seconds in arrears. Significant visible gaps between groups is the determining factor, which is why you may see 20 or more riders with the same time, then the next group is 5-10 seconds back (all with the same time) and so on. It's definitely not an exact science, but it seems that the officials do a pretty good job of getting it right.

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LeeW
Joined: 13 Jan 2004
Posts: 453
Location: near Baltimore, MD

8/22/17 9:53 AM

Yes, thanks Brian for the info and perspectives.

Since the gap must be 1 sec or larger, it is now easier to see why same time is often given out.

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

8/22/17 10:10 AM

They COULD actually be more precise

The bikes have transponders on them now, so they know exactly when they cross the line, so in theory they could give riders times to the second or even finer increments. However, that would unleash such a mad scramble on the finish of some stages that it could cause a serious safety issue and there's also the question of what to do when a rider has to change bikes. Better to stay in the "stone age" for now.

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

8/22/17 2:09 PM

Transponders accurate to.... A meter lets say?? I have no idea really, just advocating for the devil a little.

If just once the transponder did a gps jump so the 3 guy was 3 meters ahead, or 30...

:)

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JohnC
Joined: 10 Jan 2004
Posts: 1939
Location: Glastonbury, Ct

8/22/17 3:04 PM

I think you misunderstand, Sparky


quote:
Transponders accurate to.... A meter lets say?? I have no idea really, just advocating for the devil a little.

If just once the transponder did a gps jump so the 3 guy was 3 meters ahead, or 30...

:)

The transponder doesn't use gps. It's a simple RFID chip, sending a signal to the sensor on the road at the finish line, telling the system the exact time that bike crossed.

I think.

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

8/22/17 3:34 PM

I assumed gps to use over entire stage routes. But they sure could have sections/stations along the route with pickups for use on course...

Anyone know the tech used?

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Steve B.
Joined: 19 Jan 2004
Posts: 769
Location: Long Island, NY

8/22/17 6:18 PM

A riding buddy works for Dimension Data, who I think provides the tech gear and software. I'll shoot him an e-mail.

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Nick Payne
Joined: 10 Jan 2004
Posts: 2625
Location: Canberra, Australia

8/23/17 2:06 AM

In the TdF this year they trialled allowing a three second gap on flat finishes before a time gap is declared. The rationale for this was that it would make finishes safer as the riders going for GC (and their domestiques) won't all have to be up the pointy end of the finish on flat stages dicing with the sprinters and their teams to ensure they don't get the wrong side of a time cut. At 50kph, a three second gap is about 40 metres.

Froome has just come out saying that he thinks the rule should be applied in all stage races: http://www.cyclingnews.com/news/vuelta-a-espana-froome-advocates-three-second-rule-for-flat-stages/

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