I popped out to the bike tonight to do the usual weekly pre-flight checks before facing a week of riding to and from work, and quickly discovered that I'll be on the bus for a few days at least.
The rear rim has completely split for a reasonable distance around the rim. I don't know when this decided to burst at the seams, but no one heard it happen. I've had tubes blow out through the sidewall of a dodgy tyre before, but I've never seen a rim split and peel like this.
This is how I found it - it had peeled out as far as the photo above shows.
I tried to take some close up photos to show the interesting metal fatigue cracking, but my hands are too shakey to take a good photo. I need to dig out my tripod and find something to light the scene.
There's no hurry - this baby isn't going anywhere until I can find the time to visit the bike shop.