The Zurich-born rider’s breakthrough year came in 2007, riding for the KTM factory team where he took a hard-fought podium at Catalunya and finished 13th overall. The unfortunate after-effects of a mountain bike training accident saw Krummenacher rushed to hospital at the second round of the 2008 season at Jerez, and he missed further races after the emergency removal of his spleen. Struggling to regain his fitness and form for the rest of the 2008 campaign, a switch to the Degraaf team in 2009 failed to kick-start his recovery, but in 2010 he stuck with Arie Molenaar’s team and scored his best Championship classification with ninth overall in his final 125cc campaign. The Swiss rider made the move to Moto2 in 2011 with GP Team Switzerland at the controls of a Kalex machine and stayed there for 2012, during which he was once again plagued with injury problems. With the team having folded at the end of the season, Krummenacher teamed up with Technomag carXpert for 2013 to ride its Suter machine. His campaign was affected by a crash at Silverstone which resulted in him sitting out for four Grands Prix. There was another team move for him in 2014 as he made his way to Iodaracing Project, before he moved on again to JIR Moto2 for 2015.