Walter Zorn unfortunately passed away in 2009. During his life he was responsible for much innovation in cycling, and had a very methodical approach. Amongst the many things he created was an excellent speed and power calculator which many people have credited as being quite accurate. Unfortunately, the kreuzotter website is no longer on the web and I could only find the calculator on the wayback machine.
This version of the Kreuzotter calculator is as Walter Zorn's original, but modified in two ways. Firstly, the weight of the Quest velomobile has been altered to 38 kg - this being the advertised weight of Quests in 2010 (and born out by those I've weighed). Secondly, the Mango velomobile has been added, in three forms. My personal Mango Classic (with winter tyres), the current touring oriented Mango+ and the lightweight Mango Sport. The figures for aerodynamics of the Mango vs. Quest were taken from this web page and the weights for the Mangos are that of my own Mango and current production weights for the Mango+ and Mango Sport. Also, I modified the description of one of the two wheel recumbents which I previously noticed had much the same performance as my two wheel recumbent.
For me personally, this means I now have a calculator which seems to make sense for my own bikes. You may find that some of the example bikes are similar to your own.
There's more text at the bottom.
For coast-down simulations, set the Power value to zero and the Slope to the desired negative value. FAQ
Last modified: 15.4.2010
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I find it interesting to note the interactions of the effects of weight and aerodynamics on the speed of cycling. The 38 kg Quest initially appears to beat the 27.5 kg Mango Sport due to its better aerodynamics. However, select just a 0.5% hill to climb and the Mango Sport gains an advantage over the Quest due to the difference in weight becoming a greater influence than the difference in aerodynamics.
Outside of the rather artificial environment of a velodrome, there are gradients everywhere. A 0.5% gradient is really not very much at all. It's almost too gradual to see. Even "flat" areas of the world like the Netherlands have plenty of gradients at least as steep as this. Between work and home I have a number of (very) small hills which I go up and down, and my home is about 15 m higher in altitude than my work.
Add in the effect of the lower weight every time you have to build up speed again after traffic lights or when filtering through other traffic, and a Mango is relatively spritely in real life conditions.
If you're comparing with a different bike, be realistic about weight. Some bikes are advertised with very attractive low weights, but by the time you've added mudguards, racks, lights, a toolkit, spare tubes, a pump, a little luggage etc. the weight is probably higher than you think it is. Remember that the velomobiles come with mudguards, racks, lights, and even the equivalent of a raincoat.
The figures I've added to the calculator can of course only approximate real life, as can also be said for the original figures in the calculator. Don't expect to be able to cycle in any real world situation at exactly the speed the calculator gives.
The code which generates this web page can be easily viewed. Simply save the web page, and also fetch the javascript and css files. If you believe I've made any mistakes in adding the Mango figures, let me know.
Saturday 17th update. I found figures for the Alleweder (from the same source as above), and also comparisons with the aerodynamics of the Versatile/Orca and Leitra (from Adventures of Greg) so I've added these to the calculator too. I'm a little less sure of their accuracy than of the Mango figures, but they seem about right. i.e. Alleweder which I've ridden a little is quicker than my PDQ but slower than a Mango. What I find most interesting with these extra figures is the comparison between Versatile and Leitra. The Leitra generally is shown to be a little quicker than the Versatile, and it's almost entirely a function of its lower weight. Add an incline and it does quite well, amongst the velomobiles it comes second only to the Mango Sport with a 5% hill.
Sunday 17th July 2011 update. Yesterday, a blogger accused me (not via email directly to me, but on his own blog without even telling me) of changing the results of this calculator to favour the Mango over his Quest. He based this comparison on the re-appearance of the calculator on the Kreuzotter website, saying that this "original" calculator gives different results to my modified version. He is right that the results are different, but there is a much more innocent explanation than subterfuge. The calculator on the Kreuzotter website has a different version of code and gets different results to that which I retrieved from the wayback machine and modified. Other people also have copies of same version as I do, including noping.net (no longer available). Their calculators give the same results for the same inputs as mine does (be careful, not all default values are the same). I am not sure as yet whether the version of the calculator on the Kreuzotter website is an updated version of what I have or an older version which has been restored. However, unfortunately it does not have the extra velomobiles defined. If you want to make a comparison between different bikes then probably either calculator will work with a reasonable degree of accuracy. Any inaccuracy in one calculator vs. another will be approximately equal for one bike vs. another in the same calculator. Making comparisons between one calculator's results for one bike and another calculator's results for another bike will not give an accurate impression. Therefore, to compare a Quest with a Mango or other velomobile, please use my version of the calculator as it is the only one which has data for these other machines. Finally, note that this is just an online calculator. It can only ever give an estimate of actual performance.
