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

  • Successful_Try543@feddit.org
    2·
    8 hours ago

    the magnitude of the rotational inertia […] is roughly the same or maybe a bit higher on larger wheels that are probably heavier

    The rotational moment of inertia increases a lot due to the larger diameter, J ~ m r^2. Even if the masses were the same, the relatively heavy tyre and the rim are further away from the wheel hub.

    Edit: If we neglect the wheel hub and the spokes, the mass of the tyre and rim scales with the radius, m ~ r, and thus J ~ r^3 .