Back on track!

After a not-so-great Stage 5 prediction, we hit Stage 6 to better than 3%.  Below is the comparison of the actual winning time to our prediction.

• Stage 6:  5h 05' 34" (actual), 4h 56' 51" (prediction), 08' 43" fast (-2.85% error) 

I'll be traveling again tomorrow, so I'll have to check the online results when time avails itself.

One great precition, one not-so-great prediction ...

Stage 4 finished for us rather well, but not so well for the riders involved in the controversial crash.  It's a shame Peter Sagan won't be in the rest of the race.  He is a great cyclist to watch, but his elbow cost him a chance at another points title.  I'll also miss seeing Mark Cavendish, who was the unfortunate recipient of Sagan's elbow.

Today's Stage 5 had a grueling climb at the finish, but cyclists completed the stage much faster than we anticipated.  We thought perhaps a little energy would be kept in storage today, but only three of the 193 cyclists were slower than our prediction.

Below are comparisons for the past two stages.

• Stage 4:  4h 53' 54" (actual), 4h 48' 37" (prediction), 05' 17" fast (-1.80% error)
• Stage 5:  3h 44' 06" (actual), 4h 04' 49" (prediction), 20' 43" slow (9.24% error)

When I return from traveling, I'll need to look at Stage 5 more closely and determine where we were slow.  The first part of the stage to check will be the final climb.

Below are predictions for the next four stages.  That will take us to the first rest day on Monday.

• Stage 6:  4h 56' 51" (prediction)
• Stage 7:  4h 56' 08" (prediction)
• Stage 8:  4h 51' 54" (prediction)
• Stage 9:  5h 11' 15" (prediction)

With Chris Froome in the yellow jersey and the big climbs still to come, can anyone keep him from winning his fourth Tour de France???

So far, so good!

I'm currently in West Virginia while traveling.  I had to sneak a few minutes away from other activities to report on the first three stages of the Tour de France.  Our model is doing well!  I thought we might be a tad slow on the time trial, and we were, but we've nailed Stages 2 and 3.  Below are the comparisons for the first three stages.

• Stage 1:  0h 16' 04" (actual), 0h 16' 48" (prediction), 44" slow (4.56% error)
• Stage 2:  4h 37' 06" (actual), 4h 42' 08" (prediction), 05' 02" slow (1.82% error)
• Stage 3:  5h 07' 19" (actual), 5h 04' 57" (prediction),  02' 22" fast (-0.77% error)

It's great being under 2%, not to mention being under 1%!  I'll try to check in on the next two stages and then get more predictions online while on my travels.  Team Sky certainly looks strong again this year!

Predictions for First Five Stages

I see that I made a mistake in my previous blog post.  I wrote that the Tour de France begins this Sunday, but of course it begins tomorrow, which is Saturday.  My research student has accumulated terrain data and I've run the data through my model.  I won't be able to watch the first few stages as I'll be traveling.  I'll thus put our predictions for the first five stages in today's post and then do my best to comment on the results when I'm able to do so.

• Stage 1:  0h 16' 48" (prediction)
• Stage 2:  4h 42' 08" (prediction)
• Stage 3:  5h 04' 57" (prediction)
• Stage 4:  4h 48' 37" (prediction)
• Stage 5:  4h 04' 49" (prediction)

Stage 1 is a short time trial.  I always worry that we'll be a bit slow, especially when such a time trial takes place at the start of the race when cyclists are well rested.  Will a new time-trail record be set tomorrow?  I'll be checking in when I can.  Stages 2 and 4 are flat stages with a few small climbs.  Stage 3 is hilly and Stage 5 is definitely medium-mountain with a category-1 climb at the finish.

I will have to do a lot of reading and catching up when I finish traveling.  In past years, riders have taken the first couple of stages a bit easier than later stages.  We've been a tad fast early in the race on the flat stages.  I'll be curious to see if that's the case this year.

Return to Blogging and Tour de France

It has been 281 days since my last blog post.  I have missed writing about the Cubs winning the World Series after 108 years of rebuilding.  A thrilling overtime Super Bowl passed without a word from me in this space.  I've missed a lot of opportunities to write.  Even the ongoing 2017 FIFA Confederations Cup in Russia has been off my radar (will Germany take it???).  The reason for my long absence is that a personal tragedy befell me just eight days after my last blog post -- nine months ago today.  Many friends, family members, and colleagues have kept me going during incredibly difficult times, but none more than my two wonderful daughters.  They remind me on a daily basis that I can survive inconceivable betrayal.

To those of you who have contacted me in recent months and asked about my blog writing, I offer a heartfelt "thank you" for your interest.   I hope to return to more regular blog writing, beginning with the upcoming Tour de France, the 104th edition set to begin this Sunday in Düsseldorf.  My former student, Chad Hobson, who helped me with the past three Tours de France, graduated Lynchburg College last May and is off to study physics at the graduate level at University of North Carolina at Chapel Hill.  This summer I have Ryan Wainer, a rising high-school senior in the state of New York, working with me.  He has collected terrain data and I'll run them through the latest model that Chad and I put together after last year's race.

I will not be able to put the kind of detail into my Tour de France blog posts that I have inserted in the past.  But I will get predictions up soon.  I can't wait to see if anyone can knock off Chris Froome!  I also hope to get a blog post written that highlights my appearances on Star Talk Radio.  It's good to stroll my fingers across a keyboard once again.

Fun Time Chatting Sabbatical Research!

I thoroughly enjoyed giving the first Science Gang talk at my college yesterday.  Speaking about my research is a lot of fun for me.  My talk's theme was friction, a topic that included not only my sabbatical research, but elements of friction existing between people and places.  For example, political divisions are so wide these days.  It seems as if some of the friction between people on different sides of the political spectrum could be alleviated by getting together and engaging in civil conversations.  Instead so many of us have ensconced ourselves with people who agree with us, websites that share our opinions, and even online searches that filter based on our preferences.  It wasn't hard during our travels abroad to notice lots of different types of friction between people, both in today's world and in the past.

Moving from friction between people to my friction research was a welcome transition.  Many in my audience had not been exposed to much physics, so I kept the friction science light.  The photo below shows me discussing some friction basics (click on the image for a larger view).

The room was a dark and a colleague was kind enough to grab a photo with a cell phone.  I was happy to receive a photo.  I got some great questions after I finished, giving me more to ponder.  There is always more to learn!

Talk on Monday the 19th

I will give a public lecture on Monday, 19 September at 4:30 pm here at Lynchburg College.  My talk will be the first Science Gang lecture of the current academic year.  It will be held in Hopwood Auditorium.  A flyer for my talk appears below (click on the image for a larger view).

I will discuss the research work I did at the University of Sheffield in England during my sabbatical.  Topics include friction between tennis shoe and hard court, soccer aerodynamics, and Tour de France modeling.  Because friction was such an important part of my research, I'll make connections to other types of frictions seen during our travels throughout Europe.  Check out my talk if you find yourself in the Lynchburg area on Monday the 19th.

How fast could YOU swim Burj Khalifa?

Getting my family moved back to the US from England and preparing for a new semester at Lynchburg College have greatly reduced the amount of time that I've had available for watching the Rio Olympics.  I certainly won't be able to write blog posts at the rate I did during the 2012 Olympics in London (click here for a summary of what I wrote back then).  Despite how busy life for me is right now, I've been thrilled and moved watching the majesty of Simone Biles (born on Pi Day in 1997!) and the rest of the US women's gymnastics team, the continued dominance of athletes like Usain Bolt and Michael Phelps, and the emotional win for Thiago Braz da Silva in the pole vault.  But one event really took my breath away, and that was the women's 800-m freestyle.

Katie Ledecky (born on Saint Patrick's Day in 1997, just three days after Simone Biles!) so dominated that event that I wondered if she would finish, hop out of the pool, and then enjoy a cool drink while watching the rest of the field finish.  She shattered the world record, setting the new standard for excellence at 8:04.79, which was more than 11 s quicker than silver medalist Jazmin Carlin of Great Britain.  Ledecky's average speed was 1.65 m/s or 5.94 kph or 3.69 mph.  Consider that a typical walking speed is about 5 kph (3 mph), which means that Ledecky swam faster than someone walking over a distance of 0.8 km (0.5 mi).  I'm not in terrible shape, but swimming a half mile is a fairly daunting thought for me.  Doing so in anything close to eight minutes would be impossible for me!

How about more perspective on what Ledecky did?  The tallest building in the world is Dubai's Burj Khalifa.  From ground to tip, the building stands 829.8 m (2722 ft) tall.  Elevators in that building are incredibly fast, with speeds of 10 m/s (36 kph or 22 mph).  That's Usain Bolt speed, but Bolt can only sustain that average speed for 100 m or so.  I'm impressed that Bolt could keep up with Burj Khalifa's elevators for about 20 floors.  But I'm equally impressed that Ledecky could swim the entire length of Burj Khalifa in about 8.5 minutes.  Thinking "outside the pool" sometimes helps me gain better perspective.

Back in the US!

I suppose this is the last of my sabbatical journal entries on this blog.  We are back in the US after my wonderful sabbatical year at the University of Sheffield.  The last week in Sheffield was a lot of fun.  My daughters were out of school and got to spend time with their friends.  Both my girls made me proud, not only with their schoolwork, but with their ability to acclimate themselves to living in Europe for a year.  They missed their Virginia friends and will be glad to see them in a few days, but they made good friends in Sheffield that they'll surely miss in the coming weeks.

My research work advanced significantly during my sabbatical.  I learned a great deal about friction, especially the interaction between rubber treads and hard courts.  Teaming up with colleagues in the Department of Mechanical Engineering at the University of Sheffield gave me the opportunity to further my understanding of friction and publish our novel studies.  We still have more work to do!  Working with Matt Carré during my two sabbatical years has been a joy.  I can't recommend highly enough collaborating with someone outside your area of expertise.  My approach is that of a physicist; Matt's is that of an engineer.  Our different ways of seeing problems and tackling solutions led to very fruitful research efforts.  Working with his students and postdocs was rewarding, too.  Young and fresh eyes view problems in interesting ways, and I don't mind learning from someone half my age.  Advancing scientific understanding isn't about ego; it's about pursuing what is true about the universe.

I also enjoyed new collaborations with a couple of engineers at Sheffield Hallam University.  Simon Choppin and John Kelley gave me new ways of looking at trajectory analysis when studying the flight of soccer balls.  I again benefited from engineering eyes looking at a problem I was used to seeing with a physicist's eyes.  And of course I continued working with my Japanese colleagues, Takeshi Asai and Sungchan Hong, at the University of Tsukuba.  We continued to combine my trajectory analysis and computational skills with their engineering and wind-tunnel skills to further what we know about soccer ball aerodynamics.  Working with engineers has helped my career more than I can describe here.

Equally important to me are my collaborations with Lynchburg College physics students.  Chad Hobson has made significant contributions to my soccer aerodynamics and Tour de France research.  Chad and I presented some of our work at ISEA 2016 in Delft, the Netherlands.  I am always looking for good physics students to research with me.  If you are a prospective student looking to contribute to sports physics, come to Lynchburg College and work with me!

There are many things I will miss about living in Sheffield.  I'll miss not having a car and using public transportation to get everywhere.  I'll miss my gym at Ponds Forge, which I hit six days in a row before we left Sheffield.  My family will miss the cute neighborhood we lived in where every kind of shop one could want was in short walking distance.  We'll all miss Endcliffe Park and the walking trails, playground, and ducks there.  I'll miss the chance to walk across the street to the Lescar for a pint.  I'll miss living in a place where guns aren't allowed -- for sure.  And of course I'll miss the Peak District, which is one of my favorite places on Earth.  We made one last visit to the Peak District the day before we left England and had to stop at the Fox House, one of our favorite Peak District pubs.

Before touching down in the US, we stopped for a few days in Iceland.  We stayed in Keflavík, which is a lovely little town on the water in the southwestern part of the country.  Visiting the Blue Lagoon was a must, and we thoroughly enjoyed ourselves there.  I had never been to a geothermal spa before and that one will be tough to beat!  The day after we were at the Blue Lagoon, we rented a car and explored the southwestern part of Iceland.  It was like driving on the set of a science fiction movie.  That is one interesting country to look at!  We stopped first at Gullfoss, a truly beautiful waterfall (click on the image for a larger view).

I took that photo on Wednesday, 27 July 2016.  Was that just two days ago?!?  Our second stop was to see Strokkur.  I shot a movie of the geyser doing a double belch (as I called it!).

Our third and final stop was Þingvellir, a meeting place for the North American and Eurasian tectonic plates.  Two plates are separating, but I thought I would help (click on the image for a larger view).

My arms might need to be a little longer!  We certainly enjoyed ourselves in Iceland and we want to go back so that we can explore some more.  But when?

As I wrote to start this post, my sabbatical journal writing ends now with the end of my sabbatical.  I can't emphasize strongly enough how important it is to interact with people from different countries, cultures, and backgrounds.  My wonderful wife introduced me to that concept on a trip to Japan we took in the summer of 2001.  She has been helping me appreciate that concept ever since.  And she makes all of our travel seem effortless and smooth.  I'll be back at work in my Lynchburg College office on Monday, 1 August 2016.  Waiting for me is research work from Sheffield and a pile of work related to the upcoming fall semester.  But I've got another year of wonderful memories dancing around in my head!

Greipel gets us under 1%!

André Greipel took the last stage of this year's Tour de France.  His time and a comparison with our prediction are given below.

• Stage 21:  2h 43' 08" (actual), 2h 41' 38" (prediction), 01' 30" fast (-0.92% error)

We'll definitely take that error to finish off this year's race!  Greipel's average speed is given below.

• Stage 21:  11.54 m/s (41.56 kph or 25.82 mph)

The big prize, of course, goes to Chris Froome who makes it three out of four.  Froome is now in the upper echelon of Tour de France cyclists.  I was wrong to pick against the defending champion!  Froome's average speed is given below.

• Chris Froome:  11.00 m/s (39.60 kph or 24.61 mph)

Not bad for 3528.5 km (2192.5 mi)!  Congratulations to Froome and all the cyclists for a great Tour de France.  I wish I could have seen more of the race, but my family will soon be moving across the pond.  And we've got packing to do!

Izagirre gets penultimate stage!

Jon Izagirre of Spain won this year's final mountain stage.  Spain can celebrate its first Tour de France stage win this year!  Izagirre's winning time and a comparison with our prediction is given below.

• Stage 20:  4h 06' 45" (actual), 4h 01' 44" (prediction), 05' 01" fast (-2.03% error)

I'll definitely take a 2% error on today's stage!  Izagirre's average speed is below.

• Stage 20:  9.895 m/s (35.62 kph or 22.14 mph)

Chris Froome will win this year's Tour de France tomorrow in Paris.  He has just over a four-minute lead on second place.  Our prediction for the lovely ride into the French capital is given below.

• Stage 21:  2h 41' 38" (prediction)

I hope it doesn't rain like it did last year!

Bardet makes France proud!

Romain Bardet gave France its first stage win of this year's Tour de France.  Below is Bardet's time and a comparison with our prediction.

• Stage 19:  4h 14' 08" (actual), 4h 04' 57" (prediction), 09' 11" fast (-3.61% error)

I'll take that error on such an arduous mountain stage.  Bardet's average speed is given below.

• Stage 19:  9.575 m/s (34.47 kph or 21.42 mph)

Froome still has the yellow jersey, and he widened his lead over second place.  Nairo Quintana could only cut ten seconds off of Froome's lead over him.  Tomorrow is the last shot climbers will have to take down Froome, but his lead looks mighty impressive for the final mountain stage.  A category-2 climb, two category-1 climbs, and an HC climb will have cyclists excited about the big downhill finish.  Our prediction is given below.

• Stage 20:  4h 01' 44" (prediction)

Will Froome hold the yellow jersey?  Hard to imagine losing it the way he's cycled this year.

Has Froome locked it up?!?

Chris Froome showed why he's a multiple Tour de France champion today.  He dominated the mountain time trial and makes me wonder if the Tour de France is over.  His winning time and a comparison with our prediction appear below.

• Stage 18:  30' 43" (actual), 29' 27" (prediction), 01' 16" fast (-4.12% error)

I was hoping the winner would come in under half an hour, but Froome was impressive nonetheless.  His average speed is below.

• Stage 18:  9.224 m/s (33.21 kph or 20.63 mph)

Froome won the first mountain stage and he dominated the mountain time trial.  I picked Nairo Quintana in my TOUR magazine interview.  Froome has a 04' 37" on Qunitana, and a nearly four-minute lead on second place.  There are two more mountain stages to go.  Time is running out!  Our prediction for Stage 19 is below.

• Stage 19:  4h 04' 57" (prediction)

Besides an HC-climb in the middle, a category-1 climb finishes the stage.  Another uphill finish!

Zakarin dominates the Alps!

Russian Ilnur Zakarin won today's arduous mountain stage with a time nearly a minute faster than anyone else.  This is Zakarin's first Tour de France stage win.  Below is Zakarin's winning time and a comparison with our prediction.

• Stage 17:  4h 36' 33" (actual), 5h 00' 10" (prediction), 23' 37" slow (8.54% error)

What's funny for me watching a stage is that I don't root for our prediction unless at the end I think we are really close.  I wanted to see the elite tackle today's mountains and come in under five hours.  And did they ever!  Check out Zakarin's average speed below.

• Stage 17:  11.12 m/s (40.03 kph or 24.87 mph)

That speed is 2 kph faster than what race organisers had as their upper limit on the time schedule.  Incredible to average 40 kph today!  We aren't happy to be more than 8% off today, but we'll have plenty to study when the race is over.  Several determined cyclists clearly outputted more power today than we had in our model.  We'll have a clearer picture of elite cyclist power output after this Tour de France is over.

Tomorrow's Stage 18 is a 17-km (11-mi) mountain individual time trial.  Cyclists will be back in France for the uphill time trial.  They'll get a chance to sprint on the downhill finish, though.  Our prediction is given below.

• Stage 18:  29' 27" (prediction)

I definitely want to see cyclists coming in under half an hour tomorrow.

Stage 17 Prediction

I'm busily getting items packed for our big move across the pond next week.  It hit me this afternoon that I'd not put our Stage 17 prediction online.  Well here it is:

• Stage 17:  5h 00' 10" (prediction)

Cyclists will compete in the Swiss Alps tomorrow.  A great category-1 climb to the 1527-m (5010-ft) peak at Col de la Forclaz will tire cyclists.  But they'll have to rejuvenate on the descent because the HC-climb to Finhaut-Emosson at elevation 1960 m (6430 ft) will challenge even the most elite cyclist.

Sagan gets 3rd stage win!

Peter Sagan has really discarded the bridesmaid label in this year's Tour de France!  I can recall so many stages in past years when he just missed out on winning a stage.  Below is Sagan's winning time and a comparison with our prediction.

• Stage 16:  4h 26' 02" (actual), 4h 46' 38" (prediction), 20' 36" slow (7.74% error)

We're not happy with that error!  I don't see any indication of tailwinds or anything similar that would make cycling fast today.  As I wondered at the end of yesterday's post, sprinters must have been going all out today.  Check out Sagan's average speed below.

• Stage 16:  13.09 m/s (47.14 kph or 29.29 mph)

That is incredibly fast, especially for a 209-km (130-mi) long stage.  Even race organisers didn't think the average speed would be above 44 kph.  To match Sagan's time (and the time of several other cyclists), our model cyclist would have needed nearly 21% more power output.  We've done really well on a few stages this year, and we've had weather and teams' strategies thwart us on a couple of other stages.  But we will have to take a closer look at today's stage.  Tour de France cyclists certainly impress us!

Tomorrow is the second and final rest day.  Cyclists will hang out in Berne, Switzerland.  Chris Froome still dons the yellow jersey.  This year's race will surely be decided in the Alps.  Get some rest tomorrow, cyclists.  You're going to need it!

Enjoyed a great time in Delft!

I'll be using this space as a sabbatical journal for another fortnight or so.  Nothing comes to a close faster than a fruitful, yearlong sabbatical in England!  But I've made the most of my time here, professionally and personally.  I've written a good bit about various trips my family has taken, but I've not written as much about my research.  There is a good reason for that.  I was waiting to publish and present significant pieces of research.  More research is set to be published, but I'll describe below some of the work that's kept me busy this past year.  My time in the Netherlands last week will be the perfect vehicle for that description.

I attended the 11th Conference of the International Sports Engineering Association in Delft (click here for the conference webpage).  I had never been to the Netherlands before.  It was fantastic!  I am both thoroughly impressed and incredibly jealous of the biking culture there.  Wide bike lanes sit adjacent to car lanes.  It was so easy getting around.  The neighbourhood where I live in Virginia doesn't even have sidewalks.  And biking is done at nontrivial risk because of speeding cars, a small fraction of which have drivers quite hostile to cyclists.  If my hometown had a biking setup like what I saw in Delft, I could easily see myself biking to work on a regular basis.  But riding on a 45-mph (72-kph) road, with some cars going well in excess of that speed limit, and no cycling lane make such an effort very unappealing.  Hopping back in my car when I return isn't exactly something I'm looking forward to.  But cycling in beautiful Delft was a lot of fun.  The photo below shows me on my rented bike in front of the conference centre (click on the image for a larger view).

I relish going to a research conference.  Meeting up with colleagues I've not seen in a year or more is just as great as meeting a slew of new people.  Besides four great keynote addresses, I attended 37 talks and gave two talks.  I couldn't see any more than that!  There were three parallel sessions, meaning lots of talks that interested me had to be missed.  As great as the talks were, the hallway discussions were even better.  Enthusiasm was contagious and it was easy getting excited about the smallest detail in another's work.  The organisers at Delft did a terrific job.  We enjoyed great food for lunches and snacks, and the final conference dinner was a blast.  I also loved getting to know people over beer and Dutch food in one of couple of lovely squares in town.  All of us had the common feeling of love for our work and passion to learn more.  I definitely left the conference with new ideas and novel ways to think about current research problems in my head.

My research efforts contributed three papers to the conference.  I like that conference papers weren't simply dumped without review into a "conference proceedings" book.  Papers for the Delft conference, like many other serious research conferences, were peer reviewed and allowed revision.  One of my papers benefited from a reviewer's insight.  Another reviewer gave good advice for the oral presentation I gave.  Peer review is an indispensable step in the advancement of good science.

Chad Hobson, my talented undergraduate physics student from Lynchburg College, joined me in Delft for the conference.  It is important to me that my research students publish and present their work.  Not all my students are able to achieve a publication, but that's a goal I've had since I began at Lynchburg College in 2002.  Chad presented our latest Tour de France work.  He is lead author on our paper (click here for that paper) and deservedly so.  His contributions to the work have advanced our Tour de France modelling in significant and critical ways.  Chad is in the middle of his talk in the photo below (click on the image for a larger view).

I've collaborated with colleagues at the University of Tsukuba on studies involving the aerodynamics of non-spinning soccer balls.  Previous work we published together showed why Brazuca was a better World Cup soccer ball than Jabulani.  I presented our current work that combined wind-tunnel experiments with trajectory analysis.  The latter approach is my speciality.  The photo below shows me in the midst of my soccer talk (click on the image for a larger view).

And, no, I'm not doing a Jedi mind trick!  The slide shows wind-tunnel force measurements, plotted in such a way as to illustrate stability, or lack thereof, in the five balls tested.  Click here for our paper.  We are getting a better understanding of knuckling effects.

My second presentation concerned part of the research I've done with my University of Sheffield colleagues.  We have investigated friction between various types of tennis shoe tread and a hard-court playing surface.  Sliding on hard courts isn't as prevalent as it is on clay courts, but it's becoming more popular.  I showed some of our treads in the slide below (click on the image for a larger view).

There are so many options for studying tread shapes and courts interacting with each other.  This research can certainly go on for years!  Our first paper on this topic is here.  We hope to have another one out soon.

Conference revelry was damped by the late-night news on Bastille Day that scores of people were killed in Nice.  And that news is on top of the seemingly continuous streams of bad news from my home country.  As I talked to people in Delft last week, I got such a strong sense of their hope and anticipation for future work.  I'm sure I exuded those desires as well.  Now think of all those killed in Nice and elsewhere.  Innocent people with hope and anticipation for their futures.  Gone.  Families ruined forever.  And for what purpose?  Making sense of the senseless is nearly impossible.  Maybe there will come a day when humans stop killing each other, but that day is a long, long way off.

Pantano gets 1st Tour de France stage win!

Columbia's Jarlinson Pantano won today's stage, his first Tour de France stage win.  Below is Pantano's time and a comparison with our prediction.

• Stage 15:  4h 24' 49" (actual), 4h 22' 06" (prediction), 02' 43" fast (-1.03% error)

Wind was not the factor today that it was yesterday, and our model got us near 1%.   We'll take it!  Below is Pantano's average speed.

• Stage 15:   10.07 m/s (36.25 kph or 22.53 mph)

Tomorrow's stage finishes in Switzerland.  Our prediction is given below.

• Stage 16:  4h 46' 38" (prediction)

The day after tomorrow's stage is a rest day.  Will cyclists increase their rest by holding back tomorrow in preparation for the Alps?  Or will they go for it, thinking the rest day will be all that's required before the big mountain stages?  We shall see!

Cavendish gets 4th stage win!

Mark Cavendish won his fourth stage of this year's Tour de France.  He won a stage in which riders fought massive headwinds all day.  One report I saw had the head wind nearing 40 kph (25 mph).  The wind killed our prediction, as seen below.

•  Stage 14:  5h 43' 49" (actual), 4h 53' 25" (prediction), 50' 24" fast (-14.66% error)

I know why we were so off, but I still hate to see so large an error.  We had that same error on Stage 3.  That stage reinforced the idea that we can be off if team strategies' are such as to hold cyclists back.  Today's stage is a reminder that not knowing the weather can lead to a bad prediction.  Check out Cavendish's average speed below.

• Stage 14:  10.11 m/s (36.39 kph or 22.61 mph)

That is incredibly slow for a flat stage, even a long one.  The slowest average speed the Tour de France time schedule makers considered was 40 kph (25 mph).  To match the time for today's stage, we would have needed to include a 10.7 kph (6.67 mph) headwind on our model cyclist -- for the entire 208.5 km (129.6 mi).  We didn't miss today's stage because of poorly implemented physics.  We missed it because we had no idea ahead of time that riders would face headwinds.  But that's part of the unknown associated with the modelling the Tour de France.

Tomorrow's Stage 15 contains two category-1 climbs and a big HC climb.  The stage features a fast descent to the finish.  Below is our prediction.

• Stage 15:  4h 22' 06" (prediction)

I like our prediction -- as long as Mother Nature doesn't get in the way!

Dumoulin Takes the Time Trial!

Tom Dumoulin of the Netherlands easily won today's individual time trial.  How appropriate that the same cyclist who won the stage when I arrived in the Netherlands last Sunday wins the stage on the day I left the Netherlands.  A great bookend for a wonderful time spent in Delft.  I'll write more about the conference in a few days, but for now, check out Dumoulin's winning time.

• Stage 13:  50' 15" (actual), 51' 42" (prediction), 01' 27" slow (2.89% error)

We did better modelling the third-place time than the first-place time, but we'll take getting a time trial to better than 3%.  Dumoulin's average speed is given below.

• Stage 13:  12.44 m/s (44.78 kph or 27.82 mph)

Now that's fast!  I can't even fathom going nearly 45 kph on a bicycle for more than a few seconds, and that's just Dumoulin's average speed.  Well done!

Chris Froome came in second today and extended his overall lead.  Below is our prediction for tomorrow's 208.5-km (129.6-mi) flat stage.

• Stage 14:  4h 53' 25" (prediction)

Enjoy the stage, sprinters, because more mountains are on the way!

Crazy Stage 12!

Stage 12 was cut short by 6.5 km because of incredibly fast winds at the summit of Mont Ventoux.  Thomas De Gent of Belgium won today's truncated stage.  His winning time and a comparison with our pediction are given below.

• Stage 12:   4h 31' 51" (actual), 4h 37' 31" (prediction), 05' 40" slow (2.08% error)

We'll definitely take that error on a botched final climb with crazy weather!  De Gent's average speed is given below.

• Stage 12:   10.88 m/s (39.19 kph or 24.34 mph)

Below is our prediction for tomorrow's individual time trial.

• Stage 13:   51' 42" (prediction)

I wish I could comment more on today's stage but I was tied up with the last day of a great conference in the Netherlands.

Sagan gets #2!

Peter Sagan won a very fast Stage 11 today.  Below is Sagan's winning time and a comparison with our prediciton.

• Stage 11:  3h 26' 23" (actual), 3h 45' 22" (prediction), 18' 59" slow (9.20% error)

Sagan's average speed is given below.

• Stage 11:  13.12 m/s (47.24 kph or 29.35 mph)

I confess that I am stunned by that average speed.  Cyclists were fast today!  I can't imagine that average speed for myself.  Tour de France cyclists are the best of the best for sure.  Did they know ahead of time that tomorrow's massive climb to Mount Ventoux was going to be cut short because of massive winds at the summit?  They had to know they'd not need to save as much energy for tomorrow.

We learned that the final 6.5 km of tomorrow's last climb will be cut from the stage.  Below is our original prediction, our original prediction for the final 22 km, and our prediction based on removing the final 6.5 km.

• Stage 12:  4h 55' 23" (prediction)
• Stage 12:  58' 54" (prediction for final 22 km)
• Stage 12:  4h 37' 31" (prediction with final 6.5 km missing)

If the race committee does exclude the final 6.5 km, we'll go with the last time on the above list as our prediction.  It's too bad the final climb has to be cut short.  We've been waiting on that climb since it was released.

Matthews grabs Stage 10!

I enjoyed a great first day of research talks here in Delft, the Netherlands.  The conference is off to a good start!  But being tied up all day in a conference means I couldn't see any of the Tour de France.  I'm back in my hotel room for a few minutes before heading out to dinner.  Below is Michael Matthews' winning time and a comparison with our prediction.

• Stage 10:   4h 22' 38" (actual), 4h 32' 45" (prediction), 10' 07" slow (3.85% error)

I wish I could comment more on the stage, but I'll take being under 4% today.  Matthews' average speed is given below.

• Stage  10:  12.50 m/s (45.01 kph or 27.97 mph)

Not bad, considering that first big climb.  Our prediction for tomorrow's flat stage is given below.

• Stage 11:  3h 45' 22" (prediction)

We could be a bit slow tomorrow if the sprinters go crazy.  But they better not get too tired.  What awaits them on Stage 12 will make them pay for going all out tomorrow!

Stage 10 Prediction

My student, Chad Hobson, and I are having a great time in Delft, the Netherlands.  I saw old friends today that I'd not seen in several years.  We also met several new people and toured the labs at Delft.  Nothing like being around people excited about research!

Below is our Stage 10 prediction.

• Stage 10:   4h 32' 45" (prediction)

Read about tomorrow's medium mountain stage online.  I'm having too much fun in Delft and need to get back on my bicycle and explore the city!

Dumoulin takes Stage 9!

I've been travelling all day and I missed yet another Tour de France stage.  Nothing like being in Europe and not watching the best bike race on the planet!  Below is Tom Dumoulin's winning time and a comparison with our prediction.

•  Stage 9:  5h 16' 24" (actual), 5h 02' 33" (prediction), 13' 51" fast (-4.38% error)

From what I read, there were thunderstorms at the finish.  Did that slow riders down and lead to the above discrepancy?  Please e-mail me and let me know!  I love it that Dumoulin is from the Netherlands, and I'm in the Netherlands right now!  I'm here for an international research conference.  My student, Chad Hobson, is here, too.  We are checking out the Euro 2016 final while I'm writing this blog post.  Portugal just won it!

Below is Dumoulin's average speed.

• Stage 9:  9.719 m/s (34.99 kph or 21.74 mph)

Tomorrow is the Tour de France's first rest day.  I'll get our Stage 10 prediction up before tomorrow comes to a close here in the Netherlands.  Until then, we'll be happy with our prediction today.

Froome grabs the yellow jersey!

Oh how I wish I could have seen today's stage!  We have friends visiting from the US and we showed them Sheffield for the entire day, from a traditional tea to a pub visit to time in the park.  But I missed Stage 8 as Chris Froome dominated the competition to take the yellow jersey.  Below is Froome's wining time compared to our prediction.

• Stage 8:  4h 57' 33" (actual), 4h 50' 14" (prediction), 07' 19" fast (-2.46% error)

Now that's an error we can tolerate!  We are back under 2.5%, which is great.  Froome's average speed is given below.

• Stage 8:  10.31 m/s (37.10 kph or 23.05 mph)

That's impressive!  Even though we predicted a slightly better time, Froome still completed the stage in a time that amazes me.  Well done!

From Spain to Andorra, tomorrow's Stage 9 is a 184.5-km (114.6-mi) mountain stage that will have riders battling in the Pyrenees.   Three category-1 climbs, including at the start, will have riders tired by the time they get to the HC climb to finish the stage at the ski resort of Andorre Arcalis where the elevation is 2240 m (7349 ft).  Our prediction is given below.

• Stage 9:   5h 02' 33" (prediction)

I fully admit that we are predicting a fast time.  Come on, climbers, challenge Froome tomorrow!

Steve Cummings wins a FAST stage!

Tour de France cyclists never cease to amaze me.  They set a torrid pace today.  Below is the winning time for Steve Cummings and a comparison with our prediction.

• Stage 7:  3h 51' 58" (actual), 4h 11' 35" (prediction), 19' 37" slow (8.46% error)

We're not happy with that error!  Check out Cummings' average speed below.

• Stage 7:  11.68 m/s (42.03 kph or 26.12 mph)

 That's at the top of the time schedule range; our prediction was closer to the bottom of that range.  Cyclists enjoyed a bit of a tailwind, but temperatures were comparable to yesterday's stage.  The competition to reach the summit of Col d' Aspin was fierce and the downhill sprint that followed the climb was incredibly fast.  Kudos to the cyclists for dazzling us once again!

Tomorrow's 184-km (114-mi) Stage 8 is this year's first mountain stage.  Beginning in Pau, cyclists will head southeast through the Pyrenees to Bagnères-de-Luchon.  A massive HC-climb to the 2115-m (6939-ft) summit of Col du Tourmalet highlights the beginning of the stage.  As if that weren't enough, cyclists will tackle a category-2 climb and two category-1 climbs before a fast downhill sprint to the finish.  Below is our prediction.

• Stage 8:  4h 50' 14" (prediction)

That prediction amounts to a fast day of racing.  We want to see racing tomorrow like we saw today!

Cavendish gets #3 this year!

Mark Cavendish picked up his third stage win in this year's Tour de France.  Cycling was a bit slow today.  The peloton took it easy at times and cyclists seemed to be affected by the heat.  Temperatures got to about 30 C (86 F), which is hot enough to be bothered when one's cycling competitively for nearly five hours.  Below is Cavendish's winning time and a comparison with our prediction.

• Stage 6:  4h 43' 48" (actual), 4h 21' 26", 22' 22" fast (-7.88% error)

We were a bit fast today, though I think the heat played a role in slowing cyclists down a little.  Below is Cavendish's average speed.

• Stage 6:   11.19 m/s (40.27 kph or 25.03 mph)

Had we know about the heat, we might have pulled the power down a little.  But our model has done really well on four of the six stages so far, although we messed up one of those four when we cut the power too much.  We were under 8% today, which was something we thought of as good a decade ago.  Now we want to do better!

Stage 7 is 162.5-km (101.0-mi) long medium-mountain stage that begins in the commune of L'Isle-Jourdain.  A category-1 climb to the 1490-m (4888-ft) summit of Col d'Aspin near the end of the stage will introduce the riders to the French Pyrenees.  I can't wait to see that climb!  After the summit will be a downhill sprint to Lac de Payolle.  Our prediction is below.

• Stage 7:   4h 11' 35" (prediction)

Did cyclists save some energy today for tomorrow's big climb?  If so, we could be a little slow.  But we'll see how the model performs tomorrow.

Our model does the job today!

After yesterday's disastrous decision to drop cyclist power output by 20%, and thus missing the chance to have publicly predicted Stage 4 to 0.24%, we put our trust in our model for today's Stage 5.  It sure paid off!  Belgium's Greg Van Avermaet got his second career individual stage win in the Tour de France, and he wrested the yellow jersey from Peter Sagan.  Below is Avi's winning time and a comparison with our prediction.

• Stage 5:  5h 31' 36" (actual), 5h 29' 33" (prediction), 02' 03" fast (-0.62% error) 

It's great being back under 1%!  Below is Avi's average speed.

• Stage 5:  10.86 m/s (39.08 kph or 24.29 mph)

Given the climbs in today's stage, that's an impressive average speed.

Tomorrow's Stage 6 is a 190.5-km (118.4-mi) flat stage with an impressive downhill just 23.5 km (14.6 mi) into the stage.  Beginning in the commune of Arpajon-sur-Cère, cyclists will head southwest to Montauban.  The Pyrenees are getting closer!  Below is our prediction.

• Stage 6:  4h 21' 26" (prediction)

We're sticking with our model -- no power tweaking.  I'll be anxious to see if we've figured out Stage 6.

Kittel sprints to victory!

Yesterday's stage and today's stage provided us with a real learning experience, and a humbling one at that.  Last year was the first time we made adjustments to our model while the Tour de France was taking place.  We tried to make tweaks based on strategies we thought were in play.  For the most part, our adjustments worked extremely well.

Now to today's learning experience.  Marcel Kittel won today's stage 4 with the time given below.

• Stage 4:   5h 28' 30" (actual), 5h 56' 59" (prediction), 28' 29" slow (8.67% error)

After yesterday's enigmatic slow stage, we thought cyclists were holding back, saving energy for later stages.  Given that today's stage was longer than yesterday's stage, we thought power outputs would be reduced again.  As I noted yesterday, we would have needed to cut power by a third to hit yesterday's time.  We decided to cut power by 20% today, thinking we'd see another slow stage.  We should not have done that!  I cringed when I saw that had we not altered our model by reducing the power, we would have missed today's stage by just 47".  Getting spooked by yesterday's stage caused us to think that teams' strategies were such that we had too much power for the long, flat stages.  We should have seen yesterday as an anomaly and trusted our model for today's stage.  But we can't go back in time and claim a great prediction today.  Our model performed great; we misread the cyclists' strategies.  Part of good science is being as honest as possible.

Below is Kittel's average speed.

• Stage 4:  12.05 m/s (43.38 kph or 26.95 mph)

We are going to trust our model for tomorrow's Stage 5, which is a 216-km (134-mi) medium-mountain stage that starts in Limoges, where Stage 4 ended.  Cyclists will head southeast to the mountain resort of Le Lioran.  Two category-2 climbs near the end of the stage should make for great racing.  Our prediction is given below.

• Stage 5:   5h 29' 33" (prediction)

We'll stick with our original prediction and hope racing tomorrow is more like today than yesterday.