The SRAM Apex 1 rear derailleur pairs a Roller Bearing Clutch with X-HORIZON geometry to keep chain tension controlled and shift force low, cutting down on chain slap and ghost shifting over rough terrain. The long cage handles up to a 42-tooth cog, and a large upper pulley offset automatically adjusts chain gap as the derailleur moves across the cassette. What Our Gearhead(R) Experts Are Saying:"I've locked the cage out of the way with CAGE LOCK to swap a wheel trailside without fighting chain tension the whole time. That one step turns a fumbly roadside fix into something I barely think about."