Once you've been riding for a while, you really start to feel every little nuance of the bike. Am I feeling a bit of vibration of grinding through my feet? Does my bum detect some wheel wobble?
This morning, I definitely started feeling wobbling from the back end, and it had nothing to do with last night's dinner. I stopped, checked the tyres and wheels and spokes, but detected nothing out of place. When I spun the back wheel, everything was true.
But as soon as I started riding, I felt a bit of wobble. Not much wobble - just enough to start getting concerned.
It was worse when I left the office. I stopped again and had a look, but there was nothing to be found.
Once I got up to speed, the wobble disappeared. And then I was moving quite nicely down George St at 40km/h, when the back tube let go with a really loud bang. A few pedestrians crapped themselves. Thankfully, the tyre stayed on the wheel and I was able to come to a controlled stop in a driveway. I pulled the tube out and found a good sized tear in it - but still no indication of what had gone wrong.
A really close inspection of the back tyre showed that the side wall was giving way in one spot - it didn't bulge or show up when I was off the bike, but when you add my weight, it clearly had problems. The side wall obviously gave way enough for the tube to burst.
So it was off to the nearest bike shop to buy a new tyre and fit it on the footpath, as I got to the shop 5 minutes before closing, and they were bringing down the door as I walked in. Changing a tyre and tube on a busy footpath is not the most elegant thing you can do, but I am long over being embarrassed by that sort of situation.
Anyway, now I know - next time I feel wobble, it's definitely time to change the tyre.