VAVERT INNER TUBE 26X1.75/2.1 SCHRADER VALVE (40MM) Vavert inner tubes are made from high quality durable material and come in a various range of sizes from 12 x 1.75 up to 29 x 1.75. Vavert inner tubes also cover mountain bike tyres accommodating sizes up to 700 x 35/43c. They also have the option of either a Presta or Schrader valve type.