All available race results Piet Kooyman
| Date | Race | Rank |
| 23/08 | World Championships Road Race (Amateurs) | 5 |
Rider information for 1952
| Rank | 415 |
| Score | 72 |
| Name | Piet KOOYMAN |
| Country | Netherlands |
| Team | Individual |
No results available in season 1955.
Rider information for 1955
| Rank | 972 |
| Score | 9 |
| Name | Piet KOOYMAN |
| Country | Netherlands |
| Team | Individual |
| Date | Race | Rank |
| Ronde van Nederland | ||
| 13/08 | General Classification | 32 |
Rider information for 1956
| Rank | 729 |
| Score | 17 |
| Name | Piet KOOYMAN |
| Country | Netherlands |
| Team | Maggi |
No results available in season 1957.
Rider information for 1957
| Rank | 1064 |
| Score | 4 |
| Name | Piet KOOYMAN |
| Country | Netherlands |
| Team | Individual |