Originally Posted by <R16>

ROBOT elements, including software, that are designed or created before Kickoff are not permitted, unless they are publicly available prior to Kickoff.

Originally Posted by <R16> Blue Box

Please note that this means that FABRICATED ITEMS from ROBOTS entered in previous FIRST competitions may not be used on ROBOTS in the 2013 FRC. Before the formal start of the FRC Build Season, Teams are encouraged to think as much as they please about their ROBOTS. They may develop prototypes, create proof-of-concept models, and conduct design exercises. Teams may gather all the raw stock materials and COTS COMPONENTS they want.

Example 1: A Team designs and builds a two-speed shifting transmission during the fall as a training exercise. After Kickoff, they utilize all the design principles they learned in the fall to design their ROBOT. To optimize the transmission design for their ROBOT, they improve the transmission gear ratios and reduce the size, and build two new transmissions, and place them on the ROBOT. All parts of this process are permitted activities.

Example 2: The same Team realizes that the transmission designed and built in the fall perfectly fits their need for a transmission to drive the ROBOT arm. They build an exact copy of the transmission from the original design plans, and bolt it to the ROBOT. This would be prohibited, as the transmission – although fabricated during the competition season – was built from detailed designs developed prior to Kickoff.

Originally Posted by lorem3k (Post 1209327)

The rules don't mention chain drive systems, so it should be alright.