It would seem the tyres I'm running are fairly 'slack' and can easily be levered off with adequate thumbage. No need for levers. Maybe the kevlar bead is a little tired and has stretched over time.
Anyhoo, my point is the tyres move on the rim under braking and inevitably shear the valves off the inner tubes. Happened twice on the nightride last week meaning I had a long walk back to the pub.
I'm reluctant to bin the tyres as there's loadsa life left in the treads.
Other than pumping them up to 'rock hard' or going tubeless, is there some home-brew method of helping secure a tyre to a rim?