The updated AS-1 chain guard is a world-cup winner, designed for keeping the chain on a down-hill mountainbike. 
 Full installation details and bottom bracket compatibility can be found at http://www.blackspire.com/file_download/4 or you can leave setup to our workshop.
Black, for 'standard' 4 bolt, 104mm BCD chainsets. (94mm 'compact' BCD available by special order). Includes 42 tooth chainring.