Originally Posted by
ystava
What is a dual drive?
A SRAM dual-drive is a 3-speed hub mated to a 8/9/10 speed cassette drive unit. It allows up to 30 gears without using multiple chainrings. In the recumbent world, it's often used in conjunction with 2 or 3 chainrings, to allow greater total range. It's especially useful for small drive wheels in allowing not only a larger total gear range, but also standard 'high' gears without recourse to pie-plate-sized chainrings.