The Davinci Grand Junction is a great bike to look at for a couple’s first tandem. It has all the technology you could want in a tandem, extra-strong 26″ wheels, and a comfortable fit. It is a formidable value since it is our least expensive tandem, even with all of it’s features.
The most unique feature of DaVinci tandems is their excellent invention, the ICS drivetrain. The ICS (Independent Coasting System) lets each rider pedal or coast when they want to, regardless of what the other rider is doing. So you can drink when you need to, adjust your seating when you need to, or rest when you need to. It is a great feature to help a newer bike rider feel comfortable on a tandem.
Technically, the ICS is simpler than it looks. The timing chain (on the right side of the bike) is simply separated into two smaller chains, each going around a standard single speed freewheel cog. With each rider’s timing chain section running around it’s own cog, coasting becomes independent.
We’ve never had anyone request eliminating the ICS, but if you do want to, the two freewheeling cogs can simply (and cheaply) be replaced with two fixed cogs.
It is a very cool system, and is very reliable and shifts great!