This is a fixed gear/single speed bike model I created for my Arara project: https://arara.bike.
The bike model in main.blend is assembled from 5 other .blend files and contains some drivers - you'll need to click the Reload Trusted button unless you have Auto Run Python Scripts enabled in settings. It's fairly high-poly (109 723 faces) and suitable for close-up renders. There is a simple rig to link the rotation of the drivetrain and the rear wheel, and to align the rotation of the handlebar and the front wheel.
The model is licensed under the CC-BY 4.0 license. Feel free to use it for any project as long as you credit me in description (e.g., 3D model by Semyon Filippov).
Studo model in the second preview - photo studio objects by nukkio.
Enjoy! Semyon