BBB BCR-04 RoundAbout 4 Chainring Black 42T/104BCD

The BBB BCR-04 RoundAbout is a precision 4-chainring crankset component built for competitive road cycling. Featuring a 42-tooth outer ring with 104mm BCD (bolt circle diameter), this black chainring delivers consistent power transfer and reliable shifting across modern 4-arm crank systems. Engineered with durable steel construction and optimized tooth geometry, the RoundAbout ensures smooth engagement with compatible chains while maintaining the exacting tolerances demanded by performance-focused riders. Ideal for upgrading drivetrain efficiency on road bikes requiring a compact, high-quality chainring solution.