1 DIRECT-MOUNT CHAINRING
A chainring that mounts directly onto the crank axle or base of the crank arm rather than a subsidiary spider. They save weight and generally look neater, although they can be more vulnerable to impacts/warping.
2 NARROW/WIDE SRAM’s
much-copied single chainring innovation that uses alternate narrow and wide teeth that match the alternate narrow and wide chain links and help keep the chain in place on rough ground. They also help reduce wear by maximising the contact surface between tooth and chain roller.
3 GEAR INCHES
When a gear is described in inches, that’s how far the bike will travel for one revolution of the chain-set in that gear.
Shimano’s electrically-controlled shifter and mech system.
5 CLUTCH MECH
A rear derailleur with an uprated spring or friction bushing acting on the jockey wheel cage. This increases the tension in the lower segment of chain and stops it falling off the chainring. SRAM clutch mechs are fixed tension, while Shimano ones have an on/ off switch and user-adjustable tension.