Binachi measures their bikes slightly differently to everyone else.... this means that they come up a little small. so u are probably riding a 54.5cm now. I'd say that the Mercian is way too big. Your height has no bearing on the size of frame you ride. I know very tall people who ride 54cm frames and also people who are tall and ride 62cm frames. If u are comfortable with the Pista now, then stick at that size.
Binachi measures their bikes slightly differently to everyone else.... this means that they come up a little small. so u are probably riding a 54.5cm now. I'd say that the Mercian is way too big. Your height has no bearing on the size of frame you ride. I know very tall people who ride 54cm frames and also people who are tall and ride 62cm frames. If u are comfortable with the Pista now, then stick at that size.