Almost 300 tractors will be traversing the roads of south central Iowa today and Saturday. The 20th Red Rock Threshers tractor ride starts at Pella Christian High School, heading on a southern route and circling back to Pella today, while Saturday’s ride will be a northern route and also circles back to the Tulip City. A total of 285 tractors will be on this 20th ride and split into four or five different groups.