If you are thinking about renting a bike, then first spend a bit of time studying how the Thais drive. There really is no method to the madness, you have to study the idiosyncrasies to realise the shape which the traffic takes. They overtake, they under take, they might or might not indicate. They stop in the middle of the road to chat on the phone, the taxis give you no warning when they pull in to the side of the road from the outside to pick up a customer. Red lights have an altogether different meaning from those in the west. Green means go. Amber means go faster. Red also means go (if you can!) Red can mean anything, it's a multifarious light, a light with character.

Bike hire places are found all over Chiang Mai, concentrated along Moon Muang road (east side of the moat). They all rent similar bikes and prices don't vary much but it's important to check out the bike before you hire it, check the brakes and lights, and check it steers ok.