SCT-21 - Professional electric scooter tire for city commutes The SCT-21 has an outer diameter of 10" x 2.125" (50/70-6.5), and is perfectly compatible with 6.5" rim electric scooters, like Segway Ninebot F20/F25/F30/F40, D40X, Gotrax G4, and 10x2.125 tires. The thick butyl inner tube features great air retention and a 90°...