According to the IOL website, 19-year-old Jevandre Pauls and 23-year-old Craig Symons were knocked down on Polkadraai Road in Stellenbosch.
They were training for the Western Province Track Championships, which was held at the Bellville Velodrome at the weekend.
Paul is being treated in the Netcare Kuils River Hospital. His coach and manager, Barry Austin, said Pauls has swelling of the brain and severe facial fractures.
He said doctors would try to bring him out of his medically induced coma on Monday, before determining the full extent of his injuries.
Symons, a member of Ride Life Giant cycling club, said he and Pauls were cycling single file in the yellow lane when they were struck from behind.
Pauls was cycling behind Symons and was struck first.
Symons fractured his pelvis and spent most of the weekend recovering in bed after he had been discharged from hospital.
He said the driver of the car did not offer to help them, before another driver stopped and assisted them.
Police are busy investigating the incident.