Shimano CT-S500 Alfine Chain Tensioner Hanger Black

The Shimano Alfine double pulley chain tensioner is a high quality and affordable tensioner that turns your geared (vertical dropout,) bike into a singlespeed or internal gear hub compatible bike.

Designed to ensure your chain stays in place and performs at its best. The Shimano Alfine Chain Tensioner also features washers on the mounting bolt, allowing for 5mm of chainline adjustability to fine-tune your setup. 

Due to the double pulley design this tensioner can also be used to run a multiple front chainring setup with an internal gear hub, or with a singlespeed cog/freewheel if you're a special kind of wild!