Thanks All
Rims = Hope Tech XC so 19.5 mm internal width
Tyres which have failed = Trail King 2.25″ and Nobby Nic 2.25″
Schwalbe tubes at about 40 psi
Not using V-brakes! I’m pretty trad, but not that much
Actually, thinking about it, the wheels are about 6 months old and I moved the Trail Kings on to them when I got the wheels, so they survived about 3 months on the new rims, and the Nobby Nics I replaced them with managed the same. I think I need to look very hard at the rim, don’t I?