Material: aluminum Number of Rings: single Teeth: 34, 36, 39, 46, 50, 52, 53 Bolt Circle Diameter: 110mm Connection: 4-bolt Not all stock components are a fit for individual riders, so Shimano offers the Ultegra FC-R8000 Chainring to help you customize your gearing after-market. The Ultegra features improved shifting and chain retention thanks to an updated tooth design—technology that makes it harder to drop your chain and easier to maintain your cadence. Aluminum construction uses Hollowglide technology to maximize stiffness while maintaining the light weight cyclists love.