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

    • rain_enjoyer@sopuli.xyzOP
      11·
      21 hours ago

      The larger the tyre (diameter), the higher the top speed achievable practically

      this only holds when it’s using the same transmission?

      as of width, here i think tradeoff is that with wider tire you can use lower pressure, and if it’s wide enough, also lower diameter. with lower pressure i think there might be less wear (?) but also bigger width means there’s more rubber to flex and that means energy losses by this mechanism. this is why it makes sense to use wider tires where all the power is not supplied by user

      • Successful_Try543@feddit.org
        31·
        19 hours ago

        The larger the tyre (diameter), the higher the top speed achievable practically

        A larger wheel allows a smoother ride as a smaller wheel and thus allows for higher speeds on uneven ground. They also have a lower rolling resistance as their curvature (“roundness”) is smaller and thus, for identical inflation, need to be deformed less to obtain the same area of contact (which on hard surfaces, is defined by the load onto the tyre and its inflation).

        Wider tyres have a lower rolling resistance than narrow tyres when the internal pressure is identical. Thus, wider tyres can be driven with less inflation.

        See also here for more explanation:

        https://www.schwalbe.com/en/technology-faq/rolling-resistance/

      • OhNoMoreLemmy@lemmy.ml
        11·
        21 hours ago

        I think it only holds if it’s a magic engine that always hits the same max RPM regardless of load, and the transmission is the same.

        Otherwise the top land speed record would be held by a monster truck.