There's an entry in Lonely Planet's Epic Bike Rides of the World.
Their "toolkit" reads:
Start // Santiago de Cuba End // Marea del Portillo Distance // 106 miles (170km) along a rutted but easy-to-follow road. Getting there // The nearest airport is Aeropuerto Antonio Maceo, 4 miles (6km) south of Santiago de Cuba. From here there are daily flights to Havana, and direct flights to Canada. Bike hire // This is rare and unreliable in Cuba. Most serious cyclists bring their own bikes with them. Where to stay // Club Amigo Marea del Portillo (+53 23-59-70-08; www.hotelescubanacan.com); Campismo La Mula (+53 22-32-62-62; www.campismopopular.cu); Brisas Sierra Mar (+53 22-32-91-10; www.hotelescubanacan.com) When to ride // The best time is mid-November to late-March. However, the road is prone to flooding and closures. Check ahead in Santiago.