This NES game is missing from almost all lists for people looking for a complete NES collection. It is unlicensed but was available for sale in the USA. The cart is now somewhat rare and the full system is much more rare. A complete system includes the cart, interface box to the controller ports, manual, bike trainer, and handlebar display. The cart has no lockout chip or lockout defeating circuits so it must be used on a top loader or a system with the lockout chip disabled. Electrical power is used to put more resistance in the flywheel in the trainer. The speed and power output is transmitted to the NES through the controller ports where the RacerMate Challenge II game reads it and displays it on screen.
The game itself is slightly more entertaining than watching TV while biking. It mostly displays the usual stats like speed and power output. It also displays the graphics of another rider you are racing against. You can set his speed then try to keep up. Courses like sets of mountains can be selected for more challenging races. I haven't found a way to crash the bike or the other rider yet... Without the interface box, handlebar display, and trainer this game is pretty much unplayable.
The cart itself has a unique case shape and a custom mapper. To make removing the cart from front loader easier the cart has a "handle".