Why are bike tires so narrow and large diameter compared to car tires? What tradeoffs are here exactly? Motorcycle and some ebike tires are more similar to car tires than to bike tires, so i guess it has something to do with braking length at maximum expected speed, and probably also with weight of vehicle, as to not exceed some specified pressure on road. There has to be so many more reasons (weight? air resistance? some other things affecting efficiency or safety? ???)

update: apparently friction involving things that are bendy is monstrously complicated subject, and also there are material limits like maximum allowed shear stress

  • AmidFuror@fedia.io
    1·
    18 hours ago

    This is perhaps an easier to understand explanation:

    https://www.physlink.com/Education/Askexperts/ae140.cfm

    Although a larger area of contact between two surfaces would create a larger source of frictional forces, it also reduces the pressure between the two surfaces for a given force holding them together. Since pressure equals force divided by the area of contact, it works out that the increase in friction generating area is exactly offset by the reduction in pressure; the resulting frictional forces, then, are dependent only on the frictional coefficient of the materials and the FORCE holding them together.

    If you were to increase the force as you increased the area to keep PRESSURE the same, then increasing the area WOULD increase the frictional force between the two surfaces. Answered by: Paul Walorski, B.A. Physics, Part-time Physics Instructor