He showed no interest in cycling until leaving school at 16 when he acquired his first racing bike and started competing as a junior category, taking his first victory in Damme in Belgium on the 21 July 1969.

He was joint leader with Gerrie Knetemann, heading members such as Joop Zoetemelk, Ludo Peeters, Cees Priem and Henk Lubberding.

He played a major role in the victory of Zoetemelk in the 1980 Tour de France, as TI-Raleigh had one of the most dominant performances in all of TDF history not only containing Bernard Hinault, but also winning twelve stages, including seven in a row at one point.

Raas’ highlights for the rest of his career included his 1979 world championship on home soil in Valkenburg, where he outsprinted German "Didi" Thurau in front of 200,000 spectators (even with the help from team-mates that push him during the climb, grabbing service vehicle, and the fall of Giovanni Battaglin caused by Thurau and Raas himself on the last 200m).

Raas found sponsors when old ones pulled out and the team received backing from SuperConfex, Buckler, WordPerfect, Novell and finally Rabobank.