This is probably not the most common way of knowing Barcelona, however it is probably the healthiest and the most interesting one as it allows you to explore both the touristic and the real Barcelona.
In recent years, more and more private companies organize these cycling tours as an alternative to the traditional touristic tours (e.g. Bus Turistic). These tours normally take between four or five hours.
I know what you are thinking: “five hours cycling?!?! No way I am doing this”. However it is very relaxed with plenty of stops to take pictures and enjoy the city, so you don’t have to be Lance Amstrong to be able to complete the tour.
It is the ideal for those of you traveling on your own as it will allow you to meet people from all over the world, even locals.
Locals normally don’t do these tours although they should, as it would allow them to get different view of their own city and probably to discover new places within their own city.
Finally, remember that Barcelona has gorgeous weather most of the year so ensure that you don’t get burnt, use protection against sun.