Giro d'Italia 2023 Giro d'Italia, Stage 9: Savignano sul Rubicone – Cesena 35 km ITT (Sunday, May 14th)

[Krzysztof_O]

I did the computations yesterday (check one of my later posts). I used manual bisection. I was surprised how simple it was in the end - everyone goes slower for the exact same amount which is that of wind speed. Long story short: Remco wins😁

By the way - rolling resistance is the m * g * crr * … part of the equation. I only ignored gravity force (cause it’s flat) and accelerative force (cause we are assuming constant speed)

Actually cyclists shouldn't slow down exactly by wind speed: they are not airplanes (where everything depend only on aero drag). There is also rolling resistance component plus an additional velocity component (wind independent) that is present in power calculations (and is associated with pedalling speed - there should be only cyclistSpeed in your formula after P*efficiency), which is absent in jet planes (where it's all about thrust force, not power).

However, I made a program with some estimations and conclusions are generally the same. While cyclists slow down by a very similar amount (about 50-60% of wind speed) the relative difference in speed grows (and sec/km difference even more due to longer duration). I.e. for two guys with the same mass and power (one of them has CdA lower by 10%) the speeds changed from 15 vs 15.5 m/s (no wind) to 9.5 vs 10 m/s (strong head wind of 10 m/s). This translates to a significant time difference change: from 2 sec/km to 5 sec/km.

 

[Lequack]

Wind direction. There is a lot of corners today and wet roads.

https://twitter.com/x/status/1657658761538928643

View: https://twitter.com/ammattipyoraily/status/1657658761538928643

 

[Netserk]

Wind direction. There is a lot of corners today and wet roads.

As posted earlier:

 

[bNator]

Actually cyclists shouldn't slow down exactly by wind speed: they are not airplanes (where everything depend only on aero drag). There is also rolling resistance component plus an additional velocity component (wind independent) that is present in power calculations (and is associated with pedalling speed - there should be only cyclistSpeed in your formula after P*efficiency), which is absent in jet planes (where it's all about thrust force, not power).

However, I made a program with some estimations and conclusions are generally the same. While cyclists slow down by a very similar amount (about 50-60% of wind speed) the relative difference in speed grows (and sec/km difference even more due to longer duration). I.e. for two guys with the same mass and power (one of them has CdA lower by 10%) the speeds changed from 15 vs 15.5 m/s (no wind) to 9.5 vs 10 m/s (strong head wind of 10 m/s). This translates to a significant time difference change: from 2 sec/km to 5 sec/km.

Great - that finally explains it. It made no sense to me that everyone would slow down for the speed of wind. Thanks👍

 

[hayneplane]

Could you get a more vanilla TT course ? Just a matter of how much time the rest concede to Remco. Going to look like like a third week GC after this re the time gaps. Hopefully Roglic stays somewhat in touch.

The route is so dull that only watching the time splits will really provide the interest.

 

[Cookster15]

The route is so dull that only watching the time splits will really provide the interest.

Maybe Jay Vine can do well? A vanilla boring course seems a bit like a Zwift workout where he made his name.

 

[Lequack]

https://twitter.com/x/status/1657692403338280965

View: https://twitter.com/cyclartist/status/1657692403338280965?s=20

 

[Rob5091]

Rain, wind and flagstone paving; a great combination for disaster. Stay upright people!

 

[RedheadDane]

I was not expecting a history lesson about Julius Caesar when I openened my feed.
But, I guess they are starting by the Rubicone...

Meanwhile Santiago Buitrago will ride in the white jersey hand-me-down.

Huh? How can Almeida avoid wearing it today? He's not ITT Champion of Portugal.

 

[QueenStagiaire]

I was not expecting a history lesson about Julius Caesar when I openened my feed.
But, I guess they are starting by the Rubicone...



Huh? How can Almeida avoid wearing it today? He's not ITT Champion of Portugal.

Yes, I know, I forgot that Almeida was not TT champion.

 

[dazaau]

It's so wet. And there is more paint, cobbles and pot holes than asphalt on there 😳 some tight turns as well

 

[wirral]

Police blatantly motor pacing the Trek Segafredo rider.

 

[Red Rick]

It's looking absolutely miserable out there.

 

[topcat]

It's looking absolutely miserable out there.

And in here

 

[Netserk]

And in here

Sorry, didn't shower today.

 

[Savant12]

If you crash early, then you're going to be nervous and ship buckets of time.

 

[noob]

OMFG dystopian images

 

[Salvarani]

Will be a harder ITT than the profile suggested

More risky

 

[skippo12]

Willingness to take risks is going to make a big difference. Comparing Affini and Cerny a low risk approach can easily cost 3-5s per corner.

 

[Riek s]

Yeah Remco is not going to win this if it keeps like this. He is already suffering from crash-recovery and on to of that showed he won't take the risk (yesterday descend). So i'm guesssing he will loose 40seconds just by cornering alone.

 

[Didinho]

Just tuned in, miserable conditions. What's the forecast for the next hours?

 

[saunaking]

You don’t need a degree in mathematics to know that aerodynamics have more of an effect into a headwind than a neutral or tailwind

I got your math equation right here.
Diamond Legs > Darth Vader helmet

 

[KZD]

Just tuned in, miserable conditions. What's the forecast for the next hours?

It will continue to rain apparently and that could be good news for a Küng.

Affini should provide a first benchmark for the TT when he reaches the finish line in the next minutes.

 

[Barnacle Bill]

Will be interesting to see how Dennis goes here

 

[IndianCyclist]

Rain means this will end somebody's GC hopes and the R & R gap now is dependent also on bike handling & technical skills not just pure power