It's an interesting one! I'm pretty sure those frames have 1.25" headtubes and no rear derailleur cable routing as the shifter was attached to the seat clamp. Do you have matching forks?
Did Martyn ever have this built up? I remember him being on the Beast of the East frames at trials competitions until the dedicated trials geometry frames Luke mentioned.
I also remember him saying at one of the mid 1990s local trials comps soon after signing the deal that he'd asked Cannondale for a 20" trials frame like Libor Karas had (there are a few photos of that, presumably one off, frame, built with Monty parts). He said they sent him a BMX frame instead and asked if that would do.
Did Martyn ever have this built up? I remember him being on the Beast of the East frames at trials competitions until the dedicated trials geometry frames Luke mentioned.
I also remember him saying at one of the mid 1990s local trials comps soon after signing the deal that he'd asked Cannondale for a 20" trials frame like Libor Karas had (there are a few photos of that, presumably one off, frame, built with Monty parts). He said they sent him a BMX frame instead and asked if that would do.