Every Wednesday during the Tour de France I’ll be examining tactical tidbits from the week’s stages to look into key events which shape the race. Here are a few observations from the opening four days.

Stage 1: The phantom finish

Stage recap

Although it didn’t directly cause it, ‘Bus-gate’ contributed to the nervousness of an already skittish peloton which resulted in the crash that eliminated Mark Cavendish, Andre Greipel and Peter Sagan from contention for the first yellow jersey.

Less than 10km remained when it was announced that the finish would be brought forward to the 3km banner. This threw the sprinters’ teams plans into chaos. Imagine athletes in a 1,500 metres race being told with one lap left that the finish has been brought forward by 100 metres.

The net result was that teams were jostling for position even more chaotically than normal inside 5km, increasing the chance of an incident. The crash itself was initiated by Greipel, who you can see on the graphic below attempting to squeeze through a gap between two other riders. There’s a touch of shoulders – a normal racing incident, it happens – and both Tony Martin and Sagan hit the deck, joined by several others.

Cavendish is far enough behind the Slovak to stay upright, but is forced to pick his way around the resultant carnage, ending his chances.

Greipel, incidentally, does not escape unscathed. He loses his gears and a few seconds later we see him off his bike calling for the team car.

The race is then thrown into further confusion as the original finish is restored, adding back the ‘lost’ 3km. To continue my athletics analogy, imagine the runners are already starting their sprint, only to be told that they now have to run to the original finish line again.

In cycling terms, it means a sprint train uses up two or three of its men prematurely, leaving them short-handed. Argos-Shimano’s Marcel Kittel won the resultant finish, but it was a scrappy one in which all the remaining sprinters were short of lead-out men in the final kilometre.

Lotto-Belisol lead-out man Greg Henderson summed it up after the stage:

So at 6k to go we get told 3k sign is the finish. We use 3 men. 3.5k to go we get told its original final. Ufff. #confusingandfrustrating

— Greg Henderson (@Greghenderson1) June 29, 2013

I flapped around in the final but had already gone full thinking final was at 3k to go. Just frustrating. Hope everyone can start tomorrow.

— Greg Henderson (@Greghenderson1) June 29, 2013

FDJ team boss Marc Madiot – a man never short of an emotion or ten – was, shall we say, quite upset:

Madiot incandescent: “First change to finish-line was fine. We told the riders, they started to launch sprint…Second change was a joke!”

— Daniel Friebe (@friebos) June 29, 2013

It’s hard to disagree with either of them. The two changes to the finish fundamentally reshaped the outcome of the stage.

Stage 2: Running up that hill

Stage recap

On a day where the yellow jersey finished 17 minutes down, the approach to the smallest of the day’s four climbs saw the peloton hurtling at the kind of speeds normally reserved only for a sprint finish. But why?

In the grander scheme the Cote du Salario, a mere 1km in length and 98 metres high, is just a small speed bump. However, with its position 12km from the finish, an average 8.9% gradient and a fast, tricky descent, it represented real danger for the GC contenders.

Commentators are fond of stating the importance of being in the first 20-25 riders at moments such as this. They’re right – hence the breakneck pace set by GC riders and stage-hunters alike to be at the front at the base of the climb. Here are three key reasons why positioning was so important for this climb:

1. The concertina effect. A wide but sharp right-hand turn at the base of the climb meant riders at the front had to ease off, but by the time those at the back arrived the concertina effect meant many of them had to brake, killing their momentum for the climb. Before you know it, the gap from front to back is 200-300 metres.

2. Risk of incidents. A crash, a slipped chain, a puncture – anything happening to a rider in front on a climb creates another potential concertina and loss of momentum. The further back you are, the more at risk you are.

3. Covering attacks. You can’t cover an attack at the front if you’re still only halfway up the hill. Chris Froome‘s dig over the summit was a case in point. Only a dozen or so riders were in position to respond, and even then not until the Sky rider had pulled out 100 metres on the descent. Fair enough, he was eventually closed down, so no harm done. But what if, say, Alberto Contador and Cadel Evans, had been able to join up with him to form a three-man attack? Would they have been caught by their GC rivals before the finish? Perhaps not.

We’re increasingly seeing lots of stages like this at the grand tours in recent years: a short, sharp climb which disrupts sprinters and allows opportunists such as stage winner Jan Bakelants to outwit the bunch. It turned an otherwise routine medium mountain stage into a memorable one. Long may they continue.

Stage 4: It’s all about power (and aero and technique)

Stage recap

Finally, a few general comments about yesterday’s team time trial. The 25km course around Nice was flat and not overly technical, with long, straight blasts up and down the Promenade des Anglais which emphasised the importance of power, aero efficiency, teamwork and technique.

People sometimes ask whether having one great time-trialist really makes that much difference in a nine-man event. The simple answer is: yes, as it creates a virtuous circle which benefits the entire team. They can take slightly longer turns on the front, which not only means they can apply their power for longer but also affords their weaker teammates extra recovery time. Therefore everyone performs that little bit better and contributes for that little bit longer before falling away. If you have two or three top time-trialists, the benefits are immense.

It’s no coincidence that the top three teams on the day all featured multiple time-trial specialists. Stage winners Orica-GreenEDGE could boast Cameron Meyer, Daryl Impey and former world TT runner-up Svein Tuft, all multiple national champions. Omega Pharma-Quick Step had reigning world champion Tony Martin and national champions in Sylvain Chavanel, Michal Kwiatkowski and Peter Velits. Sky, despite Geraint Thomas’s fractured pelvis, fielded Froome, Richie Porte and Edvald Boasson Hagen – this quartet had all finished in the top ten at the individual time trial at the Dauphiné.

Of course, it’s not just about power. A lot is made about aero efficiency, in particular narrow-profile bike frames, aero helmets and body position. But in watching the teams, it was obvious the top squads also did two other things better than their rivals. Firstly they more consistently maintained a tight formation with minimal separation between riders. A rider can save up to 40% of their energy by sitting right on the wheel of the man in front, but every centimetre of additional separation reduces that benefit, requiring more watts to achieve the same speed.

Secondly, riders finishing their turn on the front tucked back into the pace line more efficiently. This is a difficult technique. Get it right and you drop neatly on to the wheel of the man in front, immediately receiving the resultant aero benefit. Get it wrong and you’re suddenly in energetic, disturbed air and have to push harder to regain the wheel, costing valuable energy. Get it wrong too often, and you won’t have the energy to close that apparently small gap, and you’re gone.

There was a world of difference in the teamwork and technique displayed by the top teams and the efforts of, say, Europcar and Euskaltel-Euskadi, who at times looked more like a group of casual weekend warriors than a highly-drilled professional unit. The time losses were mostly small – less than two minutes separated first from last – but far from insignificant.