Using all of their racing experience renthal have designed and developed 4x and bmx ultralite chainrings to offer the ultimate combination of lightness strength and durability all renthal chainrings are individually designed by tooth size to give the maximum strength to weight ratio we use the highest quality aluminium and the hardest wearing surface finishes to keep your renthal chainring running smoothly in the toughest conditions for as long as possible renthal bmx alloy chainri