Matthew Modine has used cycling as his mode of transportation in New York City for decades so was well prepared for the movie role
Based on a true story.
Matthew Modine and Sean Astin also starred in Memphis Belle (1990) and they both play Characters in the show Stranger Things (2016-).
Pro cyclists Phil Gaimon and Cormac McGeough worked as doubles in the descent scene.
The "real" Greg Townsend appears several times in the film. Greg's hands do the welding, and at the end when Greg clocks "four old white dudes" he is is the rider who turns back to look at the car.