You can get 27mm crown races for some headsets, or you can get the steerer cut down to 26.5mm to take a standard 26.4mm crown race, so it's not a big problem.
Always take a good look at the front BB eccentric when buying a tandem, all types are prone to stripped clamp screw threads in the hands of clumsy mechanics.
You can get 27mm crown races for some headsets, or you can get the steerer cut down to 26.5mm to take a standard 26.4mm crown race, so it's not a big problem.
Always take a good look at the front BB eccentric when buying a tandem, all types are prone to stripped clamp screw threads in the hands of clumsy mechanics.