>>6651552here's a size comparison between 1/12 and 1/18, 1/12 cars are a bit expensive (and big), so you might want to try with intermediate scales like 1/14 or 1/16, i know theres a DHL truck in 1/16
with bikes, some might be too big for school girl figmas depending on the bike (miku can't reach the handlebars for example), enduro and scooter bikes should work though