My tandems are designed to fit both riders, but I pay particular attention to fitting the stoker so that a position similar to their single bike is possible. This positioning enables both riders to cycle with the same rhythm, stand on hills and in sprints, and experience much less perceived flexing of the frame. The front end steering geometry handles much more responsively than traditional tandems, allowing the captain to steer more by leaning than by turning the handlebars. My tandems can easily be ridden with no hands if you are so inclined. The tubing is my own special mix of thin gauge oversize tubing from a variety of suppliers.
Some tubes are custom ovalized to achieve maximum efficiency and comfort.
I like to use short seat tubes with long seat posts. The frames typically weigh 10 - 10.5 lb with forks less than 2 lb. Most of my tandems are road bikes using 700c wheels and sidepull brakes. The dual pivot brakes from Shimano or Campagnolo are incredibly strong and positive, better than most all sidepulls. The Erickson Signature tandems are the most beautiful tandems in the world, winning most beautiful tandem in every show and rally they have attended.