- All of Schwalbes inner tubes are 100% recyclable and are inflated for 24 hours and tested for leaks at the factory before being shipped. Schwalbe inner tubes all have a very high butyl content and a high material purity. AV4 16" and 18" Inner Tubes * Weight: 85g * Size: 16"/18" x 1 3/8 * Schrader Valve * 40mm Valve