When deciding on the gearing you want to have on your road bike, you want to look first at the type of riding you will likely be doing most of the time. With the SRAM PG-1170 for 11-speed drivetrains, you can get pro-level of gearing starting with the 11-tooth cog and going up to the 17-tooth in one tooth increments. That tight cluster will help you fly through your gear changes without the slightest hint of grinding. Once you get a little higher up the block, the tooth jumps will be just a touch bigger with a 19, 21, 23, and then 26, in order to give you the ability to spin up some pretty steep climbs in the biggest cog. Using the SRAM PowerGlide technology, the 1170 cassette works smoothly with the chain, delivering super-fast, super-quiet shifts.-SRAM 10 and 11 speed cassettes with 11 tooth cogs have the smallest cog located behind the cassette in the packaging-Aluminum alloy lockring