Eight of the cogs are CNC-machined together out of a single block of billet steel, creating an incredibly lightweight, precise and strong cassette. The largest cog is made from 7075 T6 aluminum and the smallest cog is steel. This engineering marvel produces a 10-speed mountain cassette that is significantly lighter than other top-end 9-speed mountain cassettes.
The SRAM XX cassette features X-glide technology. X-Glide is the common denominator that gives XX its unmatched shifting performance. With X-Glide, all four upshift locations are identical and can be picked up by any outer link. Up and down shift locations have perfect timing, for an almost instant shift--even under load.
After less than 1500 miles of x-country Mountain biking over a period of 6 months the SRAM XX 10 Speed cassette failed. The failure occurred near the top of a long climb when it felt like the chain had jumped partially between to sprockets and was not engaging. Inspection found the whole cassette except the smallest gear cog able to turn freely either direction. As the small gear was usable it was used to limp home. After disassembly it was found that unlike XTR the SRAM XX cassette uses only splines on the largest and smallest sprockets to engage the cassette to the hub. These splines on had worn away on the sprocket and hub to the point of no engagement. It is recommend to avoid using this cassette if reliable long lasting equipment is required.
Cons: Low reliability