John Barr from West Saltoun in East Lothian, was cycling along the B709 Traquair to Innerleithen road at around 1.30pm on Thursday September 27 when he collided with a Honda Civic.
The 64-year-old was taken to hospital after suffering serious head, leg and pelvic injuries. He died in hospital at around 3am on Wednesday.
Lothian and Borders Police are still keen to trace witnesses to the crash.
Anyone with information is asked to contact officers on 0131 311 3131