Start choosing a tandem with both riders’ measurements and intended use. Height alone cannot describe a suitable position: leg and arm lengths matter too, along with what each person likes or dislikes about their current bicycle. Note those differences before speaking to a dealer.
The front rider has a particular responsibility: supporting the tandem when starting and stopping. Check clearance above the top tube and the ability to stand securely without obstructing the pedals. Santana’s sizing guidance also highlights body proportions when two adjacent sizes could work.
Fit the rear position separately. Co-Motion’s Primera geometry table lists distinct front and rear seat-tube and standover measurements. The manufacturer also offers an adjustable rear handlebar stem to extend the range of fitting options.
In practice, check saddle height and reach to the handlebar in both positions. Attend the fitting together and arrange a ride at the dealer. A tandem’s suitability cannot be established simply by transferring the frame sizes of two ordinary bicycles onto one longer frame.