Travel by bicycle

Adventurous travelers may wish to see Vietnam by motorcycle or bicycle. Several adventure travel tours provide package tours with equipment. Most of the population gets around on two wheels, so it's an excellent way to get closer to the people, as well as off the beaten path.
Bicycles can be rented cheaply in many cities, and are often a great way of covering larger distances. Good spots for cycling are Da Lat, Hoi An, Hue, Ninh Binh. On the other hand, attempting to cycle in Hanoi or Ho Chi Minh City is virtually suicide without proper experience of traffic rules (or lack thereof.)
In cities like Ho Chi Minh City and Hanoi, parking bicycles on the sidewalks is not allowed, and you'll have to go to a pay parking lot.

Source: wikitravel