The trek fx s 4 hybrid bike 2018 put simply means fitness it offers a best of both worlds combination of road bike speed and city bike comfort itrsquos a perfect fitness bike and so much more the trek fx s 4 hybrid is fast fun and agile enough for a multitude of uses from fitness and commuting to errands and mellow sunday loops you39ll find your ride on fx trek fx s 4 hybrid bike 2018 features all new geometry for a fast efficient goal reaching riden