As all of you might be familiar with, the well-known bike function estimating calculator ‘bikecalculator’ has helped a lot of cyclists in the past 10 years by estimating the approximate power and speed in the hill-climb when the user puts their bike information and their weight.
However, since they are based on the old experimental data, they do not reflect the increased performance of the latest bike. The estimation in the flat road is inaccurate: We can neither simulate deep wheels nor the rider’s position because CdA is set as a fixed value of 0.34. Mechanical Efficiency of Power Transmission and CRR also use the fixed value to calculate. This led me to see several limitations of the bikecalculator, especially in the GUI.
I wanted to improve these limitations. So 2 years ago, I started to develop a new bike simulator. Even though my simulator might not be ‘perfect’, I am confident that this is the most convenient cycling simulator that is out in the world. Furthermore, compared to the previous bike calculators, it provides more freedom of input for the parameter values which helped it to have a more accurate result. In order to do this, I have not only analyzed a lot of data and related papers but also have done lots of modeling and field experiments.
The physical bike simulator that I developed does not require you to sign up; of course, it is free to use. I will skip the listing of scientific formulas that I used since there are a lot of prominent physics formulas related to cycling, a lot of calculation programs, and cycling experts here. Before I start explaining my simulator/calculator, I want to let you know that this simulator contains many calculations and modeling that are based on my own perspective and the ballpark input that was inspired by various cycling experiments.
- The most differentiated part compared to the previous bike calculators is of course the GUI part. This part is built up by React and SCSS and it reflects the recently updated bike frame, tire, and the shape of the wheel.
- The CdA modeling, which is a vital part of the calculator, is based on the cyclingpowerlab’s (which is gone now) basic formula. Bassett et al. (Med Sci Sports Exerc 1999) I have searched lots of resources about body size and bike’s CdA modeling, and when it is compared with the other CFD result, I thought this was the most reasonable method. Also, in order to separate the GUI, I had to divide the rider’s upper body and bike + lower body’s CdA. At this part, I used the program that gave me a ballpark figure.
- The CdA value of the bike’s frame was referred from Specialized, Cannondale dictionary’s other frame data and wind tunnel experiments with yaw angle values.
- For the changes in the position CdA, I applied the result from several bike position papers: While modeling, for the overall value, I set the fixed value for the bike and considered the position CdA when the rider’s position changed.
- I got an idea from ‘bicyclerollingresistance’ for the CRR value. However, the CRR value that this website provides does not seem to show an accurate calculation for real-life outdoor riding. So I calculated back the CRR value based on the other formulas. The data I took a look at for this process was also from cyclingpowerlab. (Can’t this website please re-open?)
- My calculator uses different modeling with different parameters for the bike groupset’s power transmission depending on the watts from 150 to 400. For instance, for the Ultegra, the power transmission varies from 93.x to 96.x depending on the watts. This of course is based on different experimental values, and I am sure that this kind of calculation has never been applied in the previous calculators.
- For the rim height, I referred to the Hambini Engineering’s experiment but they were based on Turbulent steady flow which did not reflect the real-life value. So, I only referred to the ratios and regression function from Hambini Engineering and made my own approximate variable by the field experiment and some inverse calculations.
- I have collected several famous segments list from strava for my calculator: For each country and city, the well-known segments are already set in my simulator program so you can easily search them and put the distance traveled and the altitude. All geographical data is not always accurate and I was not able to put all the environmental factors which might cause the record difference, but if it is a steady hill-climb, the estimation will be pretty accurate.
It is hard to list all, but this simulator contains a lot of one-tracked experiments, subjective ideas, and some data sets that are altered. Please be mindful when using this: It was a way to make a better simulator. I was not a physics guy during my college time so this simulator will not be the most accurate simulator in terms of physics. However, I am proud and confident that this simulator is the most easy-to-use and detailed simulator.