If I am riding a vintage bike, I prefer to have a tube amp and vinyl setup. It takes up a bit of space, but sometimes it is best to maintain authenticity. For this application, I prefer 1972 Sansui bookshelf speakers mounted at the ends of the handlebars.

If I am using my modern bike, I prefer to bring along B&W 800D speakers, mounted on low-riders, in order to get the best soundstage. I use a Bob trailer (the one with the shock absorber) and two Class A monoblock amplifiers and a separate digital-analogue converter. The whole setup weighs several hundred pounds, but it is important to get high sound quality when on a bike ride.