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Why do tires have the width and diameter they do?
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
When synthetic dyes became available, people treated them a bit like we treated blue LEDs 10 years ago
fabric colors that were "always" available to common man were shades of everything from red to blue, white, black, brown and grays. purple was also always available, but extremely expensive.
enter coal tar era of chemistry (starting 1840s or so): aniline and later diazo dyes made fabric in all possible colors not only available, but cheap. yes initially they sucked, they ran, they weren't resistant to anything, they will give you ballsack cancer, but they were a thing. for a short time, purple fabric was a choice of the extravagant and the futuristic, and then people just stopped paying attention as it became more common
blue LEDs were sort of also used as a futuristic aesthetic choice, just after they appeared, but before these things became common, and now blue LEDs are just everywhere