aRX

Brand: SunTour

Introduced in 1981, the aRX (model 4300) was SunTour's response to Shimano's 600 AX aerodynamic groupset. It shared the modern detailing of the era, with allen-key pulley bolts and an allen-key cable clamp bolt, but cost pressures led SunTour to pair aluminium knuckles and outer plates with steel inner parallelogram and cage plates. This short-cage friction road derailleur handled a 28-tooth total capacity and up to a 26-tooth sprocket, yet quality-control troubles saw it steadily lose ground to Shimano.