## RECUMBENT versus REGULAR racing bicycle## Leo Rogier Verberne |

## 9. Tour de FranceThe recumbent high racer is longer and 2 kg heavier than the regular racing bicycles of professional cyclists (table 1). This means a disadvantage in terms of speed, because it increases rolling- and slope resistance (see the foregoing chapter). But an even greater disadvantage is the reduced pedaling power of the rider when cycling a recumbent bicycle (with the present construction of the handlebars). That reduction is yet to be objectively quantified. It is assumed here that the 1-hour pedaling power of a cyclist on a recumbent high racer is 20% less than on a regular racing bicycle. However, when cycling recumbent, the air resistance is lower, thanks to a smaller front area, which is a big advantage for the high racer. The overall effect in terms of speed when cycling recumbent compared to regular cycling has not been clarified. Because as early as 1934 the UCI banned recumbent cyclists from competitions (5). That ban is in place up to the present day. So the question whether a professional cyclist could win, for example the Tour de France, on a recumbent bicycle has never been answered.
The
recumbent high racer, his 1-hour pedaling power is an estimated 20% less than on the regular racing bicycle, so 0.8 × 450 = 360 watt. If we consider 80% of this value as his 5-hours pedaling power on the recumbent bicycle, this comes to 288 watt (table 2). This brings Chris Froome’s average speed during the 7 level stages on the high racer to 45.16 km/hour (12.545 m/s). Overcoming the intrinsic resistance of the recumbent bicycle requires 7% of this 5-hours pedaling power: Pb = 0.07 × 288 = 20.2 watt. The following applies to the rolling- and air resistance: Pr = (70 + 10) × 9.81 × 0.005 × 12.545 = 49.2 watt Pd = 0.5 × 1.23 × 0.2 × 0.9 × 12.545³ = 218.6 watt Added up Ppe = Pb + Pr + Pd = 288 watt (table 2). At an average speed of 45.16 km/hour, a stage of 191.3 km in length takes 4.236 hours (191.3/45.16).
On the
recumbent high racer, his speed of descent on the 4% slopes, without pedaling or braking, is 56.38 km/hour (15.662 m/s).Psl = (70 + 10) × 9.81 × 0.04 × 15.662 = 491.7 watt Pb = 0.01 × 491.7 = 4.9 watt Pr = (70 + 10) × 9.81 × 0.005 × 15.662 = 61.5 watt Pd = 0.5 × 1.23 × 0.2 × 0.9 × 15.662³ = 425.3 watt Psl = Pb + Pr + Pd = 491.7 watt (table 4). At an average speed of 56.38 km/hour, descending the 3 slopes combined takes 0.692 hours (39/56.38).
The 1-hour pedaling power during climbs on the
On the
Sources1. Wiel van den Broek (2017): Technische artikelen over de fiets: Vermogen en krachten 2. Harmen Lustig (2017): De bergen in de tour van 2013 3. Wikipedia.nl (2017): 2013 Tour de France 4. Wikipedia.nl (2017): Chris Froome 5. Wikipedia.nl (2017): Werelduurrecord (wielrennen) © Leo Rogier Verberne |
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