Career
Amateur career
Born in Wormer, Sinkeldam rode for the Rabobank Continental Team for his entire amateur career, between 2007 and 2011. In his youth Sinkeldam was also active in mountain biking and in cyclocross. Professional career
Sinkeldam turned professional for the 2012 season, joining the Project 1t4i team
He finished the race sixth overall.
He was named in the start list for the 2015 Tour de France. All riders were in stable condition.