Each component has been re engineered to ensure maximum stiffness performance and minimum weight dura ace r9100 crankset the shimano dura ace r9100 compact chainset has been completely re designed to offer the very best combination of light weight and stiffness it features shimano39s iconic 4 arm hollow spider that is made from hollow forged aluminium although the crank arms and spider arms are noticeably bigger which increases stiffness the overall weight has dropped by 7g over the pr