WorldwideSpainCastile and LeónFríasBU-504WorldwideSpainCastile and LeónFríasBU-504Cycling Climbs in BU-504 There are 2 cycling climbs in BU-504.Clicking on the climb category column will toggle between category and difficulty score.NameDistanceAvg GradientTotal ElevationClimb Category1.Frias-Portillo del Busto12.31 km3.7%449 mCat. 22.*ALTO TOBERA3.09 km5.4%168 mCat. 3