The pulleys are known collectively as the jockey wheels or jockey pulleys - the guide pulley is at the top of the pairing (closest to the sprockets) and the tension pulley is at the bottom, taking any slack up from the bike chain as it is fed from one of the chainset's chainring.he upper pulley is indicated as the Guide pulley or G-pulley.But oversize pulley wheels actually offer enough of an advantage in wattage savings that it may be worth sacrificing style
