yes, it's possible, and even recommended! especially for those new to riding fixed. you really only need a front brake, but having both brakes isn't a bad idea if you'd like to go that route. as far as bianchi's go, the pista will only accept a front brake, but the san jose and the fremont can do both. the pista is going to be a very "tight" bike with track geometry, the fremont a bit more lax with road geo, and the san jose is more along the lines of a cyclo-cross bike, with clearance for larger tires and slighty more lax than the fremont (in case you hadn't already found that info yourself).