Abstract: A front derailleur including an annular chain guide for engagement and disengagement of a bicycle chain with multiple chain rings of a crankset. The annular chain guide may be positioned by linear guide rods. The annular chain guide may have an inner lifting surface and an outer pulling surface for engaging diametrically opposed corners of a chain when viewed in cross-section. The annular chain guide may have an opening defined by a polygon having at least five sides. The motion of the annular chain guide during a up-shift, i.e., displacement of the chain from a smaller chain ring to a next larger chain ring includes an upward, outward and rearward linear motion relative to a bicycle frame including upward force exerted by the annular chain guide against the chain. The motion of the annular chain guide during a down-shift is exactly opposite whereby the annular chain guide exerts a pulling down force against the chain.

Abstract: A front derailleur including an annular chain guide for engagement and disengagement of a bicycle chain with multiple chain rings of a crankset. The annular chain guide may be positioned by linear guide rods. The annular chain guide may have an inner lifting surface and an outer pulling surface for engaging diametrically opposed corners of a chain when viewed in cross-section. The annular chain guide may have an opening defined by a polygon having at least five sides. The motion of the annular chain guide during a up-shift, i.e., displacement of the chain from a smaller chain ring to a next larger chain ring includes an upward, outward and rearward linear motion relative to a bicycle frame including upward force exerted by the annular chain guide against the chain. The motion of the annular chain guide during a down-shift is exactly opposite whereby the annular chain guide exerts a pulling down force against the chain.

Abstract: A front bicycle derailleur which utilizes a substantially annular chain guide for engagement and disengagement of the bicycle chain with multiple chain rings of a crankset. The annular chain guide provides an opening for the bicycle chain to pass through. The opening is sized only slightly larger than the cross section of the bicycle chain and is smooth and rounded along the inner surfaces that come in contact with the bicycle chain. The relatively small opening allows for precise and efficient positioning of the bicycle chain. The annular chain guide also serves to maintain the position of the bicycle chain to prevent derailment or unwanted shifting of the bicycle chain during pedaling.