FILTHY 50 50KM Gravel & MTB MARATHON Brgy. Carlosa, Calatagan, Batangas November 6, 2022 Filthy, Dirty, Muddy and Fun-exciting race. Participants must complete the challenging 50km course under 7 hours featuring a variety of terrain and surfaces to test cyclists of all skill levels. The route passes through back roads, single track trails (with technical features) and pave roads. There are a number of fun climbs, ‘boring’ flats and breath-taking downhill.