Join Date: Feb 2004
Location: St Peters, Missouri
Bikes: Rans Rockst (Retro rocket) Rans Enduro Sport (Retro racket) Catrike 559, Merin Bear Valley (beater bike).
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 47 Post(s)
The short answer is you can definitely upgrade to a 7-speed.
The more adequate answer can get pretty long. Potential issues include dropout spacing and repeated bent rear axles. At best, neither will crop up as a problem. Also at best, you won't be gaining much either.