5/8" Studs Installed - All coarse threads are quick start style. Our new 10" hybrid rotor is designed to fit the Pinto spindle. Complete with inner and outer races and 5/8" studs. Pre-drilled holes include 5 on 5" bolt circle spacing. This brake rotor is designed for dirt track applications and should NOT be used for asphalt racing. Thread Length:1.38 Stud Length:2.05 Stud Diameter:0.63 Flange Diameter:6.37 Rotor Thickness:0.81 Weight:14.80 IMCA Approved