Wednesday night get on my bike to cycle home and find that I have a flat tire. I walk home and fix the puncture later on that evening. Thursday morning I’m on my merry way.

Thursday night I cycle home as usual. Then just as I’m serving tea I hear a very loud hissing noise from the other room. I race in there wondering what on earth is making that noise only to see the same tire going from full pressure to flat in less that 30 seconds.

Later on when I have a look no air is escaping from around the edge of the patch – the usual culprit. But the patch itself has a very conspicuous bulge running down the middle. I’ve never seen that before!