# Calculator

This calculator is based on the theory of the Secret of Cycling.
The calculator is composed of three parts.
The first part is about your human engine (your power and weight) and the parameters who determine this (like training).
The second part is about the cycling performance that you want to achieve and the parameters who determine this (like air resistance and climbing resistance).
At the third part you can make your own calculations on the achievements of top cyclists or other cyclists.

Choose one of the three parts/tabs. Depending on your choice you will immediately see a number of subtabs.

Attention: The tab for calculating the Alpe d’Huez, gives conflicting results.
This problem will be solved as soon as possible.

Your cycling power is mainly determined by jour body weight in kg and your FTP (your Functional Threshold Power), in Watt/kg. Your FTP equals the total power in Watts divided by your weight in kg. Enter your body weight and FTP at the next tab.
Enter your bodyweight and FTP. If you do not know your FTP, go directly to the tab: Calculate the FTP of elite cyclists (or yourself).| An alternative is to estimate your FTP by using one of the first two methods, when you enter ‘No’ below.
The attainable speed decreases slowly with time. The table shows your attainable speed on a flat course and while climbing the Alpe d’Huez. Also the attainable speed of elite cyclists is shown.
Sprinters have a larger decline of the speed with time than all-round cyclists. The decline of endurance cyclists is even less. The previous tab was meant for all-round cyclists. If you are a sprinter or an endurance cyclist, you can see the impact. Enter below what kind of cyclist you are.
Your performance peaks around the age of 30 years and is less if you are younger or older. Enter your age below.
Your performance-index indicates at what percentage of the elite-runners you are cycling. Corrections are made for age and sex.
Your FTP is inversely proportional to your body weight. Especially in the mountains your weight is a large determinant of your FTP The table shows the effect of a 5 kg weight loss or weight gain. You can also adjust your body weight and look at the differences.
Your FTP is greatly influenced by training. Your FTP may increase by 10-20 %.
Your FTP may increase by 2.5 % by altitude training.
At higher altitudes the thin air limits your oxygen uptake and lowers your FTP. After a few weeks acclimatization this effect becomes less.
In this part your performance is calculated at the FTP and weight that you entered in the part on your cycling power. Your performance depends on different factors, e.g. the air resistance factor, temperature, altitude. The influence of the different factors are shown at the tabs.
The air resistance factor depends on your bike position and bike design. The standard value is set at 0,3 m2, but this value can be altered to see its influence.
The temperature has impact on the air density. At higher temperatures the air resistance is less. A standard value of 20 degrees Celcius is used, but you can adjust this value to see its impact.
The density of the air is lower at an higher altitude, which results in less air resistance. This impact is partly reduced by the secondary effect of the decrease in oxygen uptake at higher altitudes, as calculated at the part ‘Your cycling power’. The table shows the total impact of both factors. At a flat course you can benefit from the lower air resistance. Up hill, the impact of the thinner air leads to a lower performance.
In a low, the air pressure is lower and consequently also the air density and your air resistance. A standard value is set at 1013 mbar, but to see the impact you can adjust this value below.
The rolling resistance factor depends on the tire type, the tire pressure and the road type. A standard value of 0,004 is set, but you can adjust this value to see the impact.
Especially in the mountains your bike weight has a large impact. A standard value of 8,8 kg is set, but you can adjust this value to see the impact.