Originally Posted by
tatfiend
Bikes are almost exclusively Metric as are virtually all currently sold cars.
Except for things like pedal threads (1/2" and 9/16" and pitch also in tpi), bottom bracket threads of 1.37" x 24 tpi (although a width of 68mm), 1" and 1 1/8" headsets, and 1" diameter handlebars. It's still a mishmash of metric vs. British units.
Ironically for the items above there used to be readily available metric versions as well - the old French standards, but those have disappeared and now one needs to get these with British measurements rather than metric.