We have a Moda Major X CX bike, which my son uses for racing. The wheels on it are the world’s most stupid size – 26 x 1 3/8″ (650A or 590mm in ISO), and sadly the only CX tyres I have for it have reached the end of their natural life. One of them has stretched so much that they no longer stay put on the rim reliably.

Useful reference for obscure wheel sizes

I’ve considered whether I’d squeeze a set of 650b tyres onto it as they are only 6mm smaller diameter, but even then there’s not a lot of choice for CX tyres in this size.

Has anyone got any suggestions for alternative rubber for this bike before I either replace the wheels with a more sensible size, or relegate it to grasstrack (I still have a set of workable tyres for that!) and build him a 700c bike instead?