A Comparison of the Efficiency of the Bicycle with Analogous Systems in Nature

A Comparison of the Efficiency of the Bicycle with Analogous Systems in Nature

S. Burgess J. Wang R. Vaidyanathan

Department of Mechanical Engineering, Bristol University, UK.

2 June 2011
| Citation



There are several analogies of mechanical design between the bicycle and nature. The coasting ability of a bicycle is analogous with the coasting ability of birds; the chain transmission has an analogy with the four-bar linkage in bird wings; the spoke-rim wheel layout has analogies with natural structures; and the tyre is analogous with some of the shock absorbing structures in animals. Comparing optimal design in the bicycle and nature demonstrates that the bicycle is very efficient as a transport machine and as a structure. However, one key difference with nature is that coasting animals like birds avoid steep gradients by flying on a level course or by using thermals to gain altitude. Analysis of the energy demands of cycling show that uphill cycling has a major negative impact on journey times and energy efficiency. Investing in dedicated cycle paths in order to avoid steep gradients could significantly increase the take-up of cycling and this would have significant long-term environmental advantages.


Bicycle, coasting, gradients, structural efficiency


[1] Worldometer: http://www.worldometers.info/cars/.

[2] Pucher, J., Peng, Z.R., Mittal, N., Zhu, Y. & Korattyswaroopam, N., Urban transport trends and policies in China and India: impacts of rapid economic growth. Transport Reviews, 27(4), pp. 379–410, July 2007.

[3] Woodforde, J., The Story of the Bicycle, Routledge & Kegan Paul Ltd: London, 1970.

[4] Lodge, C., Theoretical and Experimental Studies of the Mechanical Behaviour of Roller Chains, PhD Thesis, Bristol University, 2002.

[5] Wilson, D.G. & Whitt, F.R., Bicycling Science, MIT Press: Cambridge, 1982.

[6] Pennyquick, C.J., Modelling the Flying Bird, Elsevier Inc., 2008.

[7] Berg, C. & Rayner, J., The moment of inertia of bird wings and the inertial power requirement for fl apping fl ight. Journal of Experimental Biology, 198(8), pp. 1655–1664, 1995.

[8] Burgess, S.C., Stolarski, T.A. & Karp, S., An accelerated life test for bicycle free-wheels. Measurement Science and Technology (Institute of Physics), 1, pp. 1–8, 1990. doi:10.1088/0957-0233/1/1/001

[9] Lodge, C. & Burgess, S.C., A model of the tension and transmission effi ciency of a bush roller chain. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 216, pp. 385–394, 2002. doi:10.1243/0954406021525179

[10] Burgess, S.C., Improving cycling performance with large sprockets. Journal of the Engineering of Sport, 1(2), pp. 107–113, 1998. doi:10.1046/j.1460-2687.1999.00012.x [11] Norberg, U.M., Vertebrate Flight, Springer-Verlag: Berlin, 1990.

[12] Michell, A.G.M., The limits of economy of material in frame-structures. Philosophical Magazine, 6(8), pp. 589–597, 1904.

[13] Burgess, S.C., The ranking of efficiency of structural layouts using form factors: part II: design for strength. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 212(2), pp. 129–140, 1998. doi:10.1243/0954406981521097

[14] Burgess, S.C., The ranking of effi ciency of structural layouts using form factors: part I: design for stiffness. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 212 (2), pp. 117–128, 1998. doi:10.1243/0954406981521088, 

[15] Herrera, M., Panchon, A. & Perez-Bacete, M., Trabecular trajectory in the articular processes of the human fourth cervical vertebra. Journal of Anatomy, 199(3), pp. 345–348, 2001. 


[16] Vogel, S., Comparative Biomechanics, Princeton University Press, 2003.

[17] Papadopoulos, P., Sölter, J. & Kremer, F., Hierarchies in the structural organization of spider silk—a quantitative model. Colloid and Polymer Science, 287(2), pp. 1435–1536, 2009.

[18] Weissengruber, G.E., Egger, G.F., Hutchinson, J.R., Groenewald, H.B., Elsässer, L., Famini, D. & Forstenpointner, G., The structure of the cushions in the feet of African elephants. Journal of Anatomy, 209(6), pp. 781–792, 2006. doi:10.1111/j.1469-7580.2006.00648.x

[19] Gill Jr., R.E., Tibbitts, T.L., Douglas, D.C., Handel, C.M., Mulcahy, D.M., Gottschalck, J.C., Warnock, N., McCaffery, B.J., Battley, P.F. & Piersma, T., Extreme endurance fl ights by landbirds crossing the Pacifi c Ocean: ecological corridor rather than barrier? Proceedings of the Royal Society B, 276, pp. 447–457, 2009. doi:10.1098/rspb.2008.1142 [20] http://www.ultracycling.com/records/24hourtrack_record2008.html.

[21] http://www.gbrathletics.com/wrec.htm.

[22] A sustainable future for cycling, Department of Transport Report, January 2008.

[23] Winters, M., Friesen, M.C., Koehoorn, M. & Teschke, K., Utilitarian bicycling: a multilevel analysis of climate and personal infl uences. American Journal of Preventive Medicine, 32(1), pp. 52–58, 2007. doi:10.1016/j.amepre.2006.08.027

[24] Dora, C. & Phillips, M. (eds), Transport, Environment and Health, WHO Regional Publications. European series 89, World Health Organisation, 2000.

[25] Chang, H.-W. & Chang, H.-L., A strategic study of bicycle tourism in Taiwan. Journal of Eastern Asia Society for Transportation Studies, 5, pp. 1675–1677, October 2003.

[26] The National Cycle Network – Guidelines and Practical Details: Issue 2, 1997.

[27] The European cycle route network EuroVelo, A truly sustainable Trans-European Transport, Network (TEN-T), Response to the public consultation of the European Commission on the Green Paper in TEN-T, April 2009.

[28] Bejan, A. & Marden, J.H., Unifying constructal theory for scale effects in running, swimming and fl ying. Journal of Experimental Biology, 209, pp. 238–248, 2006. doi:10.1242/jeb.01974