Biking is one of the best ways to explore Oaxaca City and the surrounding hills and villages. There are several places in Oaxaca that rent different types of bikes to awesome travelers like you.
Bicibella is located a few blocks north of Santo Domingo (near a ton of good spots to eat, have coffee, or Mezcal). They rent basic bikes out for five hours for 50 pesos or 12 hours for 90 pesos. They are the company that Coyote Aventuras uses for their highly recommended street art tour.
Pedro Martinez is the OG Oaxaca cyclist and his shop is very well run (it is located southwest of the Zocolo). They rent city bikes for 350 per day and mountain bikes for 500.
First off, Mundo Ceiba puts on an incredible free nightride around Oaxaca every Wednesday, Friday, and Saturday at 930 (meets at 9:30PM). Mundo Ceiba also rents basic city bikes for 70 pesos for less than 8 hours.
Zonabici has two awesome fully-stocked bike shops in Oaxaca (one downtown and one just north of downtown). They currently rent out electric-assisted bikes for 1000 per day.
*Updated January 2019