I'm a capable and intelligent Roman with command over a legion.
I've noticed when a metal plate is dropped, it can roll a fair distance in a straight line. I've read enough maths & engineering texts to understand the functionality of gears, and I have blacksmiths and leatherworkers who'll devote time to making me the frames & chairs.
Would the resources I can muster be able to generate steel frame bikes with leather seats & inflatable tyres? Could I use them to run rings around the tribes causing ruckus in Germania?
There are certain problems in the way. More can be said if anyone else would like to address themselves to the development of the bicycle; for the meantime, this question has, surprisingly, come up before, and here's some previous posts for your consideration:
More can always be said about Roman technology and just how complicated a modern bicycle actually is, but u/rocketsocks answered a related question a couple of years ago: Why did it take so long for the bicycle to be invented?