Probably on Cycling Road, in between Oreburgh City and Eterna City. 'bike guy' however, is not very specific.
Chat with our AI personalities
there is no acro bike on Pokemon platinum, you press B to change gears
from the pokech guy
the Pokemon fan club in vermilion has a guy that gives you a bike voucher
You gain it in Eterna City after saving the owner of the Bike Shop in the Galactic Building.
from the foreign guy