A partial clue is in the spell-checker, you will find wiggly red lines appearing under British English spellings on forums (fora?) using American software. "Divided by a common language" as an Irishman once wrote...
Mudguard/Fender*
Gudgeon pin/Wrist pin
Tyre/Tire
Gearbox sprocket/Counter-shaft sprocket
Colour/Color, etc...
A.
* I sincerely hope that there is some automotive component somewhere, maybe the mythical warble-flange bracket, for which the American English is "Gibson", in the interest of fairness, of course.