The only thing that should need modifying is your pain threshold the c1 chainring is a full featured crank based power meter that features dual sided measurement the fsa made one piece chainring design provides added stiffness for shifting no matter the terrain available 5339 5236 and 5036 chainring tooth options for 5 bolt 110 bcd cranks the c1 mounts to existing hardware on the bike additionally dual band ant and bluetooth smart connectivity make the c1 an obvious choice for rid