Debutants
Mads Pedersen is the youngest debutant in World Championships in 2017. There are 49 debutants.
| # | Rider | Team | Age |
|---|---|---|---|
| 1 | PEDERSEN Mads | Denmark | 21y + 280d |
| 2 | GEOGHEGAN HART Tao | Great Britain | 22y + 178d |
| 3 | EIKING Odd Christian | Norway | 22y + 270d |
| 4 | RESTREPO Jhonatan | Colombia | 22y + 300d |
| 5 | MOLANO Juan Sebastián | Colombia | 22y + 324d |
| 6 | NÕMMELA Aksel | Estonia | 22y + 337d |
| 7 | MOHORIČ Matej | Slovenia | 22y + 340d |
| 8 | RYBARUK Kostyantyn | Ukraine | 23y + 25d |
| 9 | NEILANDS Krists | Latvia | 23y + 37d |
| 10 | GHEBREIGZABHIER Amanuel | Eritrea | 23y + 38d |
| 11 | GUERREIRO Ruben | Portugal | 23y + 80d |
| 12 | SOTO Nelson Andrés | Colombia | 23y + 97d |
| 13 | MOSCON Gianni | Italy | 23y + 157d |
| 14 | MCKENNA Sean | Ireland | 23y + 200d |
| 15 | DIBBEN Jonathan | Great Britain | 23y + 224d |
| 16 | JANSEN Amund Grøndahl | Norway | 23y + 225d |
| 17 | BAŠKA Erik | Slovakia | 23y + 255d |
| 18 | NDAYISENGA Valens | Rwanda | 23y + 266d |
| 19 | ZABEL Rick | Germany | 23y + 291d |
| 20 | SOLER Marc | Spain | 23y + 306d |
| 21 | BETTIOL Alberto | Italy | 23y + 330d |
| 22 | HAIG Jack | Australia | 24y + 18d |
| 23 | LE GAC Olivier | France | 24y + 28d |
| 24 | ČERNÝ Josef | Czech Republic | 24y + 136d |
| 25 | DOULL Owain | Great Britain | 24y + 145d |
| 26 | GOUGEARD Alexis | France | 24y + 203d |
| 27 | SMIT Willie | South Africa | 24y + 269d |
| 28 | CALMEJANE Lilian | France | 24y + 292d |
| 29 | MAGNUSSON Kim | Sweden | 25y + 24d |
| 30 | SAVITSKIY Ivan | Russia | 25y + 202d |
| 31 | TEUNS Dylan | Belgium | 25y + 207d |
| 32 | ARNDT Nikias | Germany | 25y + 310d |
| 33 | BAZHKOU Stanislau | Belarus | 25y + 324d |
| 34 | JENSEN August | Norway | 26y + 26d |
| 35 | BROWN Nathan | United States | 26y + 79d |
| 36 | BIZHIGITOV Zhandos | Kazakhstan | 26y + 106d |
| 37 | KASTRANTAS Charalampos | Greece | 26y + 195d |
| 38 | BEVIN Patrick | New Zealand | 26y + 221d |
| 39 | CHRISTIAN Mark | Great Britain | 26y + 308d |
| 40 | ZHUPA Eugert | Albania | 27y + 173d |
| 41 | TRATNIK Jan | Slovenia | 27y + 213d |
| 42 | ROGLIČ Primož | Slovenia | 27y + 330d |
| 43 | PUCCIO Salvatore | Italy | 28y + 24d |
| 44 | VERMOTE Julien | Belgium | 28y + 60d |
| 45 | ČANECKÝ Marek | Slovakia | 29y + 99d |
| 46 | VILELA Ricardo | Portugal | 29y + 280d |
| 47 | IZAGIRRE Gorka | Spain | 29y + 352d |
| 48 | SHAW Damien | Ireland | 33y + 76d |
| 49 | SOBAL Yauhen | Belarus | 36y + 170d |