Trek 7.1 FX Hybrid Bike 2011 Bike Colour Navy Frame size 20in. Trek Hybrid / City Bike Trek 7.1 FX Hybrid Introduction Comfortable upright-riding bikes that make getting there as much fun as being there. Fitness is only the beginning with Trek’s most versatile line of bikes yet! The Trek 7.1 FX is the perfect blend of a fast ride with a familiar, upright riding geometry. The heads-up position offers a comfortable ride while the road bike-inspired design offers an incredibly efficient ride for anybody who’s looking to hit the pavement.