No front derailleur required.
With one-by drivetrains firmly established as a viable option in the mountain and cyclocross realms, SRAM is now in the process of expanding the one-by paradigm to the road with its Rival 1 group. The Rival 1 GXP Crankset sits at the center of the group to guide the chain through the pedal stroke with perfect lines and outstanding chain retention.
While some of us at Competitive's office remain skeptical of a sole chainring's utility in more mountainous regions, others are eager to sacrifice a top-end gear or two for the weight savings and clean simplicity of the new options. Whatever the case, this setup certainly shows promise for riders living in less aggressive topographies and may be an ideal setup to ditch the front derailleur and save some weight for crits and time trials.
The crank arms are fashioned from forged aluminum for efficient power transfer at a much lower price point than their carbon fiber counterparts. The chainring's teeth feature a distinctly tall, squared-off profile that catches the chain earlier and releases it later in the pedal rotation than standard triangular teeth, improving chain stability and retention. The teeth also have rounded chamfer edges to aid chain retention and minimize deflection. SRAM also keeps b-road adventures in mind by including recesses that help clear mud.
The SRAM Rival 1 GXP Crankset is compatible with GXP-equipped framesets with 130mm and 135mm rear spacing.