Inner Tube 110/90-18 TR4 Staight Valve Stem - fits on 4.00/4.50-18 | 130/70-18 | 130/80-18 Motorcycle Inner Tube TR4 Valve Stem for 18" Rims TR4 Valve Stem: Straight Stem, Round Shape to fit on rims with a round valve base. Fits on these Tube Type Tires: 4.00/4.50-18, 110/90-18, 110/100-18, 120/80-18, 120/90-18, 130/70-18, 130/80-18 Heavy duty durable valve stem. Unbeatable performance and value.