The specialized 650b presta inner tube is the perfect replacement or spare tube for the new 650b wheel size these tubes are the first thing we have seen from specialized in regards to the new 650b wheels and they have been moulded for a consistent thickness of butyl rubber these inner tubes are ideal for tyres with a width from 175 24 or 24 30 and they have a long 40mm presta valve for easy inflation specialized 650b presta inner tube features designed for 175 24 or