The hollowtech ii chainset features hollow forged crank arms which are both lightweight and rigid whilst being incredibly strong and durable hollowtech ii integrated bottom bracket design uses a wide bearing placement with a large axle diameter for increased stiffness efficiency and added durability hg x chainring with patented spike pins give smooth and fast gear shifts under load with a 488mm double ring chain line for use in conjunction with 135 142 mm old we recommend that the bott