Do bikes with larger wheels go faster than ones with small wheels? | Notes and Queries



SPECULATIVE SCIENCE

Do bikes with larger wheels go faster than ones with small wheels?

Richard Gray, London, UK

  • Yes; provided the wheels are turning at the same RPM.
    You have to put proportionately more effort into turning a big wheel but it will go faster if you can keep it spinning at the same rate as a small one.
    Now if you want bring in stuff like gearing and the size of the person riding it and the riding surface and and and – the answer is: it depends.

    Pete, Cambridge, UK

  • Yes and No. Small wheels spin at a higher RPM because of their smaller circumferance, but the tyre’s speed depends on how fast you’re travelling.

    VicTheBrit, Nara, Japan

  • There’s no definite answer.
    On smooth surfaces, small wheels have less aerodynamic drag due to a smaller frontal area. Smaller wheels can also be built lighter (therefore easier to propel uphill). However, larger wheels theoretically provide slightly better rolling resistance (the effect of this is incredibly small).
    On rough terrain, a larger wheel will roll more easily over obstacles/holes – imagine this – a tractor wheel will easily roll over a curb, but a rollerskate wheel would just bump into it.
    This begs the question – why do road bikes have bigger wheels than mountain bikes? The answer is probably due to an accident – mountain-bikes were pioneered in the United States by development of tough, rugged ‘cruiser’ bicycles – these happened to use 26″ wheels, and the size stuck.
    However, the trend is reversing somewhat – 29″-wheeled mountain bikes are becoming popular, and small wheels are common on some road bikes e.g. Moulton bicycles, and especially recumbent bicycles.

    Lewis, Coventry UK

Add your answer




UP