Grinder MTB Challenge Get ready for the toughest battle on the Bottelary Hills in Stellenbosch. This is a race that will challenge you. But it is enjoyable and the views are spectacular. The route is carefully planned to make this race a true, but achievable challenge of both fitness and mountain biking technical skills. This is an event with a PURPOSE. A portion of the funds go to charity. After your ride and run, relax, have something cold to drink and grab a bite to eat.