An inner tube which has correct dimensions for the Blockley 28x3 tyre size.

This inner tube is fitted with a TR6 valve stem. The TR6 is a metal valve stem that has a diameter of 8 millimetres. Blockley is manufacturing a tube to fit the 28x3 tyre size correctly, with a decent quality butyl tube having a decent 3mm wall thickness, but these will not be available until July / August time.