Police said the man, who was riding a black racing bike, was cycling down the hill towards St. Helier around 12:10 when he came off his bike.
The man suffered injuries that required hospital treatment.
Mont Felard was then closed to traffic for nearly four hours after the accident, resulting in a diversion on the Route 7 bus.
Apologies, we have a diversion on Route 7.Mont Felard is closed to traffic. The bus will miss stops both ways from town to St Lawrence Church until further notice.
— LibertyBus (@LibertyBusje) July 30, 2018
Police would now like to speak to any road users who were in the area yesterday and who may have seen this incident.
Anyone with any information is asked to contact police on 612612.
Pictured: The man was coming down the hill. (Google Maps)
They can also contact independent charity Crimestoppers anonymously on 0800 555 111 or via their Anonymous Online Form.