Yesterday, British hopes were dashed as Geraint Thomas blew up in the last 2k of the Giro d’Italia. This led to a lesson for all of us – leave something in the tank for a TT with a hill at the end.

What happened in the race?

In a thrilling penultimate stage mountain time trial at the 2023 Giro d’Italia, Primož Roglič defied a mechanical setback to emerge victorious and claim the pink jersey from Geraint Thomas of Ineos Grenadiers.

Despite facing a setback when his chain slipped due to a pothole during the climb, Roglič demonstrated remarkable composure and accelerated through the remainder of the ascent. He not only managed to recover but also outperformed Thomas by an impressive 40-second margin, securing the stage win.

With only one ceremonial stage remaining in Rome tomorrow, Roglič’s triumph in this stage virtually guarantees his overall victory in the race. Despite being the second fastest rider on the day, Thomas relinquishes the pink jersey that he had held for a significant portion of the competition, falling short at the final hurdle.

During the stage, Primož Roglič received an immense amount of support from a large contingent of Slovenian fans. They crossed the nearby border to cheer him on, proudly waving their nation’s flag adorned in blue, white, and red. The fans passionately chanted Roglič’s name, providing him with an extra boost of motivation and energy.

Expressing his gratitude at the finish, Roglič acknowledged the tremendous impact of the crowd support. He attributed his success partly to the enthusiastic fans, stating, “I had the legs, and the people they gave me extra watts.”

However, while Roglič basked in his triumph, his victory came at the expense of Geraint Thomas. Thomas had appeared poised to secure the overall victory and potentially become the oldest champion in Giro history. Unfortunately for Thomas, Roglič’s glory meant a sudden reversal of fortune, transforming his anticipated triumph into a heartbreaking disappointment.

Pacing a TT with a climb at the end

Everyone reading this knows that to pace a TT with a climb at the end you need to distribute your energy differently to how you might pace a totally flat time trial. We saw a little bit of this on stage one of the race but the climb was not as severe as the one the riders faced in the final TT.

Essentially, Thomas ran out of gas and it’s likely he would not have lost as much time if he’d have paced the flatter portion at the start a little more sensibly. To get a more concrete example of this, we will head into myWindsock – where all the stages from UCI races can be analysed by premium users.

An exaggerated example:

Stage 20 of the Giro provides a perfect example of an exaggerated TT with a hill at the end, there are many of these up and down the country including my own favourite course – the P164 in the New Forest. To further exaggerate the example we will use two scenarios, an evenly paced ride at 350W throughout (as if the rider was on erg mode) and a version where the rider does 300W on the flat and 400W on the climb. As the climb is quite long, this makes an 18W difference to the overall average power. How much time does 18W save? On a flat 25m TT, this might be around a minute.

Evenly paced ride:

Now we shall see what time savings can be achieved with riding the flat section a touch easier and the climb a touch harder with all the same parameters…

A better paced effort

Using myWindsock to pace an effort

1. Access myWindsock: Visit the myWindsock website or download the myWindsock app on your device. Create an account if needed.
   
2. Input your time trial course: Enter the details of your time trial course into myWindsock from our library of CTT courses.
   
3. Set your target time: Specify the time you want to achieve for your time trial and myWindsock will do the rest.

Welcome to myWindsock – Sign up here!

The UCI rules dictate a number of measurements cyclists must follow when setting up their time trial bikes. The nice thing about the UK is that we are not beholden to these rules very often as we follow CTT or British Triathlon, depending on whether or not we are doing a triathlon or a time trial… 

What do the UCI rules say?

The UCI (Union Cycliste Internationale) is the governing body for professional cycling and sets rules and regulations for various disciplines, including time trial racing. Time trial events are individual races against the clock where cyclists strive to complete a specified distance in the shortest time possible. These races require specialised equipment, and the UCI has established rules to ensure fairness and safety.

In terms of bicycles, UCI time trial rules dictate specific guidelines. The bike’s weight must not be less than 6.8 kilograms. The frame’s design must comply with UCI regulations, including specific tube dimensions and angles. The handlebars must be at least 3 cm wide at all points and may not extend beyond the front wheel axle.

UCI rules also stipulate that the front wheel must be the same diameter as the rear wheel, generally 700c. The use of disc wheels, also known as solid or full carbon wheels, is allowed, but they must meet UCI regulations regarding depth and dimensions. Additionally, time trial bikes are typically equipped with aero bars or triathlon bars to allow riders to maintain a more aerodynamic position. The exact dimensions and measurements of this position depend on a rider’s height, but CTT and triathletes are not beholden to these measurements. 

UCI regulations also cover clothing and equipment. Riders must wear a skinsuit, which must not extend below the knee. Shoe covers, overshoes, and other accessories must comply with specific UCI guidelines to ensure fair competition. Skinsuits cannot have external air tripping technology attached, such as the Endura D2Z skinsuit which triathletes wear a version of and is commonly seen at CTT events. 

What happens outside of these regulations? Enter “villager’s”…

Outside of these regulations, you can see some pretty obscene positions and equipment – as pioneer of rule bending (and incredible athlete) Graham Obree demonstrates in the video below.

These UCI rules aren’t followed in triathlon and we see riders going faster and faster for less power as was demonstrated in the recent Challenge Championships with riders averaging upward of 45kph with close to only around 300W.

Challenge Championships Samorin is a long-distance triathlon race held annually in Šamorín, Slovakia. It is part of the Challenge Family series, which is a global triathlon series featuring a variety of events worldwide. The race takes place in the x-bionic® sphere, a large sports and leisure complex in Šamorín.

We set off to myWindsock to work out how aero triathletes actually are. Having done a little bit of estimation and some messing around with numbers on a segment called “villager’s” from the race, we came up with some aero data from the race. You can see the forecast of the segment (where Funk has the KOM) here.

Using what we could tell from Funk’s Instagram (and looking up rolling resistance data) as well as using his Strava activity for the ride we estimate his cda to be just under 0.18 – this is similar to Graham Obree’s super tuck position shown in the Youtube video embedded above! Triathletes are FAST!

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If you’re not worried about UCI regulations and like going fast, all of the CTT courses are available on myWindsock and can be used in planning for your race!

The Giro d’Italia 2023 route reveal made the time trialists very happy and as a result, many have turned up. According to Pro Cycling Stats’ time trialist ranking system, 4 of the top 10 time trialists in the world have turned up including Ganna and Remco Evenepoel. Top GC time trialists like Tour de France winner Geraint Thomas and Olympic TT champ Primoz Roglic have also turned up – it’s fair to say winning a time trial at the 2023 Giro d’Italia is one of the hardest things to do in pro cycling this year. The line-up is so strong I’ve not even mentioned Kung or the fact that the current TT world champ, Tobias Foss, had to pull out as he contracted covid at the Tour de Romandie. 

The second of three time trials, and the longest of the three, takes place on Sunday the 14th of May and is the flattest of the TTs – one that was made for heavier riders like Kung and Ganna.

The course includes a number of twists and turns and will likely favour riders who are able to take these corners in their aero bars.

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The forecast

No preview would be complete without a myWindsock forecast. Our previous analysis went up on Instagram and was even mentioned by Rob Hatch on Eurosport. 

The forecast at the time of writing predicts strong headwinds at the start of the day. Obviously, this is subject to change – if you’re wanting an up to date prediction of the conditions click here.

How fast will the contenders go?

Remco Evenepoel put in a thermonuclear time trial on stage one to win, full results can be seen here and we can use this, along with data released by Velon to work out how aero he was and how fast he might go for the TT on Sunday. The time to beat for GC contenders will be around the 40 minute mark.

The myWindsock (plus a bit of guessing from Tom) estimate for Remco’s time…

Due to the length and how flat the TT is, along with the fact that Remco didn’t look himself yesterday, on paper Kung should be favourite. Using numbers that we’ve seen in the past from him we can predict the following from FDJ rider… 

As with anything though, there are a number of factors at play including how well riders have carried form from one day to the next. One thing that could also dictate the results is how conditions are changing throughout the day. Keep up to date on our Instagram for ongoing analysis.

The question of whether or not weight matters on a bicycle is always a hotly debated topic. Usually, it’s the case that the penalties of weight loss are not worth the effort but losing weight can make a difference on hilly courses. A while ago, Ben (the founder of myWindsock) wrote a very popular blog post on how much difference 5kg can make on a course which you can read here. 

Why does weight matter?

Weight matters in cycling because the less weight a cyclist is carrying, the less energy they have to expend to maintain a given speed or climb a hill. This is because of the physics of cycling – as a cyclist pedals, they have to overcome two main forces: air resistance and the force of gravity.

Air resistance is determined by a combination of the cyclist’s speed and their frontal area (which is affected by body position and equipment). The faster a cyclist goes or the more upright they sit, the more air resistance they encounter. However, the effect of air resistance is relatively small compared to the force of gravity when cycling on a slope.

The force of gravity is determined by the cyclist’s weight, the slope of the road, and the acceleration due to gravity. When cycling uphill, the force required to overcome gravity increases with the slope of the road and the weight of the cyclist and their bike. The steeper the hill, the more important weight becomes.

What kind of course should I be more worried about weight than aero?

Since Ben wrote his blog, I’ve considered this question further as I have entered an off-road triathlon with a 30km bike course with 1000m of climbing total in the two laps. A scenario where weight will play a bigger role than aerodynamics on large parts of the course. Let’s see what myWindsock has to say about the course… 

The race details…

The race that I’ve entered is an Xterra branded triathlon. For those of you that don’t know, Xterra is an off-road triathlon that typically includes a mountain bike leg. The bike courses for Xterra races are usually off-road and can include singletrack, fire roads, and technical terrain. The courses are designed to be challenging and often include steep climbs, rocky descents, and other obstacles. The one I’m racing is Lake Garda, in Italy – which is extremely hilly. 

A quick interlude on rolling resistance

One of the challenges around predicting an off road course can be rolling resistance, obviously it will vary as the surface is not the same throughout. The rolling resistance of mountain bike tires can vary depending on several factors, including the tire size, tread pattern, rubber compound, and inflation pressure.

Typically, the rolling resistance of mountain bike tires can range from around 10 to 40 watts per tire at a speed of 20 km/h on a smooth surface. However, when riding on rough terrain, the rolling resistance can be significantly higher due to the increased friction between the tire and the ground.

It’s worth noting that a lower rolling resistance typically translates to faster speeds and better efficiency, but it can come at the cost of reduced traction and durability. On the other hand, tires with higher rolling resistance may provide better traction and durability, but may be slower and less efficient. Therefore, the choice of tire depends on the rider’s priorities and the type of terrain they plan to ride on.

The coefficient of rolling resistance (Crr) is a measure of the frictional resistance between the tire and the ground, and it is typically expressed as a decimal or percentage of the tire’s weight. For mountain bike tires, the Crr can vary depending on the factors mentioned earlier, but typically ranges from around 0.004 to 0.02.

This means that for every kilogram of weight on the tire, there is a force of around 4 to 20 Newtons opposing the motion of the tire. Again, the actual Crr for a given tire can vary depending on factors such as the tire size, tread pattern, rubber compound, and inflation pressure.

How much difference does a kilogram make?

Putting in our advanced settings we can have a look into how long the course might change based on weight savings. Using our initialised settings we can see the following…

One thing that’s interesting to note is the distribution of forces, despite cda being estimated very high at around 0.4 we notice, using the force distribution graphic, that most of our resistance comes from gravity.

What happens if we lose a kg or two?

If you want to plan your next race to the last detail, check out myWindsock and sign up today!

Personally, I was interested in working for myWindsock because I am a time trialing (and general performance) nerd but one thing I’ve learned is that myWindsock has a variety of uses, one of which is riding outside a little more. 

I love training, but I hate the rain. I have a confession for you all – I am a triathlete. Cycling in the rain is much worse than running in the rain. Cycling in the rain can be unpleasant for a few reasons. First, getting wet is uncomfortable and makes me cold, especially if the temperature is cool. This can be exacerbated by the fact that, no matter how much money you spend, waterproof jackets run out of facilities eventually. 

Where I live at the moment, we have quite a lot of rather large mountains. That can make packing for a ride very tricky – but I don’t have my turbo with me here so I’m riding in the rain if it’s raining. Weather forecasts in mountainous regions can be less accurate than in other areas due to the complex terrain and microclimates that can exist within mountain ranges. The topography of mountains can influence the weather patterns in a variety of ways, such as creating orographic lifting, which can cause air to rise and cool, leading to increased precipitation. The weather can change fast in the mountains, making myWindsock vital.

The topography of mountains can also make cycling rather tricky. Obviously a ride with 2000m of elevation in 85 km can take a little longer than a ride with my usual 400m of elevation in this distance. Planning is tough here – a 75 km loop could take anywhere from two and four hours. Obviously planning my life around riding, planning food for rides and choosing what to wear requires a tool a little more advanced than the weather app on my phone – enter myWindsock.

Using myWindsock to plan a ride

If you don’t know anything at all – read our guide on using the planner. Otherwise…

• Go to myWindsock website at https://mywindsock.com/ and sign up for an account if you don’t already have one.
  
• Once you’ve entered your ride details, myWindsock will generate a wind forecast for your ride. You’ll see a graph that shows the predicted wind speed and direction at various times throughout your ride as well as the probability of rain.
  
• Use the wind forecast to plan your ride route. Try to choose a route that minimizes the amount of time you’ll be riding directly into the wind. You may also want to plan your route to take advantage of tailwinds.
  
• You can also adjust your ride start time to take advantage of the best wind conditions and avoid the rain. For example, if there’s a strong headwind predicted for the morning, you may want to delay your ride until the afternoon when the wind is predicted to die down.
  

If you live somewhere with changeable weather (hello to everyone in the UK all year round!) then you might find planning rides with myWindsock makes your life that bit easier. Sign up here!

Time trials are an interesting discipline and all of you reading this will likely have found yourself in a position where you’ve done one of the following… 

1. Gone way too aggressive with your position and lost huge amounts of power 
2. Not gone aggressive enough and been beaten by riders doing much lower watts 

Both of these two options are sub optimal and the best way to address them is a good bike fit, to convince you of its importance though we have decided to take a look at the consequences of getting it wrong on a CTT time trials course by using myWindsock to help us make sense of the data.

CTT and myWindsock

Before we do that though, a little interlude on how you can check a CTT event in the myWindsock app. 

All time trials in the UK are available on myWindsock, head to myWindsock and click planner where you’ll be able to click on the UK Time Trials option.

What happens when we get the balance wrong?

So, armed with this new information on how we can view CTT events in myWindsock – let’s check out Reading CC’s club 10 for the 4th of April as an example. Clicking ‘view event’ we are presented with the following forecast… 

Let’s imagine our test rider can do 350W for 20-ish minutes with a moderately aggressive position. The cda we might see for this sort of position will be around 0.250±0.2 for a 70-80 kg male rider, the cda for a female would be a tad lower as women tend to be smaller so have a lower frontal area. This gives us a time of 22:32 for this 10 mile course, pretty handy. 

Our rider then makes some adjustments, goes super narrow and drops his saddle down to get as aero as possible – throwing comfort and power production out the window. Due to this, he’s suddenly limited at his maximal aerobic power, which for a rider who has a 20 minute critical power might be around 275W, but his cda is now 0.19 – let’s see what happens to the time… 

We see that our rider is suddenly 30s slower over 10 miles. Now let’s imagine our rider does the opposite and suddenly veers the other way – raising their stack really high, going wider and moving the saddle back up high to maximise power production. Imagine they achieve a 20 minute power of 370W in this scenario but suddenly have a more typical road bike cda of 0.350, what happens to the previous time of 23:03? 

Suddenly we are faced with a scenario where our rider is doing 100W more than the aggressive position yet going much slower! 

These numbers are exaggerated slightly to illustrate a point but the fact remains that a balance must be struck between aerodynamics and comfort. 

Key takeaways

1. Time trial positioning is a 3-dimensional problem. The time you’re able to complete a course is a function of power and cda – finding the minimum of this function is essentially the art of time trialling boiled down to mathematics!
   
2. 3D calculus is relatively hard in the scheme of maths, luckily myWindsock does this for you as it calculates a predicted time based on power and cda, all you need to do is play with the numbers to find the best option for you.
   
3. Usually, when striking a balance between aerodynamics and power production – lean towards aero but don’t overdo it. This way you can get quite close to the optimum without being overly aggressive and risking injury.
   
4. Get a bike fit… 

If you want to perform to the best of your ability at your next cycling time trial open or club event, use myWindsock to check the forecast and plan your ride accordingly. Turn data into information and race with confidence.