Biking is very popular in Spain and the province of Granada certainly is one of the most varied places to visit by bike. The lifts in the skiing resort are available for bikers in summer.
There is a great variety of places to rent bikes in case you do not bring your own :
Sierra Nevada Bikes
Sierra Nevada Bike Park
Ride Sierra Nevada
Ride Sierra Essence
If you want to do some research on trails, we recommend a website called Wikiloc