Angled valve stem Our 8-1/2″x2″ tire and tube set for kick scooters is in a size that sometimes hard to find if you don’t have Monster Scooter Parts here for you This is the correct size for a number of the popular Trikke carving scooters 30 Day Warranty Description Our 8-1/2″x2″ tire and tube set for kick scooters is in a size that sometimes hard to find if you don’t have Monster Scooter Parts here for you. This is the correct size for a number of the popular Trikke carving scooters. In addition, there are a half dozen or so gas or electric scooters that took this rubber, but there are doubtless many more. So if your kick scooter uses this relatively rare size, then you can always count on Monster Scooter Parts to have just what you need.