For club racing i start them larger at around 1.9 rear and 1.8 front. For high bite or for a real competitive race i run them about 1.750 rear and 1.650 front. In 19 turn i usually get about 9 or 10 runs on a set of tires and in mod around 5 or 6 runs(Larger tires). For the small tires they are 1-2 run tires