A chain oiler system (10) for a vehicle comprises an oil reservoir (11) having both user operated means and movement sensing means operating in combination to control valve means supplying lubricating oil to a dispenser attachment (30) supplying oil to a drive chain. The dispenser attachment has means (32) for adjustable attachment to a bicycle derailleur jockey wheel and oil inlet (34) and outlet (33) means for receiving oil from the reservoir and dispensing oil to a bicycle chain respectively. The oil outlet means is in the form of a spray nozzle (33) arranged to supply oil onto the face of the jockey wheel the rotation of which causes the oil to transfer to the chain as it passes over the jockey wheel.
