18 months back I bought some "easy-fit" inner tubes, own-brand from Halfords (UK - is this a UK site?). They weren't circular, just long straight tubes which had to be fitted round inside the tyre with a slight overlap. They were magic - you can replace a punctured tube without taking off the wheel, disconnecting the gears etc - just lever the tyre off one side of the wheel, ease out the old (straight) tube to mend later, and thread the new one in.
I'm not much of practical person, but with one of these, a pump and a couple of levers , I could go from flat-tyre to back-on-the-road in 7 minutes (my record). This was a complete transformation after all my previous Forty-minutes-and-six-spanners-later-Oh-my-god-how-do-the-gears-go-back-I'll-have-to-push-the-bike-all-the-way-home disasters.
They also have the advantage that to a large extent "one size fits all" - with 4 bikes in the family, all different sizes, we could just take one of these on a trip and with more or less overlap they would sort out whoever got the puncture. Someone always did.
I thought these were the best thing since sliced bread, but now Halfords has stopped making them, and my set of spares is wearing thin. I've phoned a dozen branches and they all say they were "no good" and they aren't made any more. No good? Uh? What????
Does any one know an alternative supplier?????