Sram xg 899 e bike x glide cassette 8 speed the ex1 drive train was designed specifically for the demands of electric assist mountain bikes a wide gear range with bigger jumps between gears and sturdy components to handle higher torque loads liberal use of features found on srams high end mtb parts provide high value quiet operation and ease of service machined from case hardened tool steel cogs are designed to work specifically with inner and outer chain links for precise up and down shif