Wtb 27 5 mtb tubewtbs 27 5 mtb tube is a durable inner tube that is robust enough to keep you rolling yet lightweight so it doesnt feel overly bulky in your jersey pocket this inner tube also features a presta valve featuresmaterial 6061 aluminiumvalve prestasize 27 5weight 635gbuy wtb wheels tyres from chain reaction cycles the worlds largest online bike store