So having installed the new chainring I thought the day is sunny and I have half an hour free time. Why don't I take the bike for a little rattle down the local treelined hill, and see what shakes out. No sooner do I leave the house and get up the road than there is a horrible clunking noise from the back. A regular little skip like a heart beat gone wrong, and a rattle and a clunk that sounds like the chain wants to move to the next gear socket. Then the chain falls off at the front.
Okay.... so perhaps I have miscounted the links on my chain and so its the wrong length. Only I could have sworn I had measured correctly. Perhaps then I have not adjusted the rear derailleur for the new front chainring? This seems like the easiest problem to start on, and so armed with my trusty screwdriver I set about the limit screws in attempt to solve the problem by the roadside. 10 minutes later and I limp the bike home clunking like the mechanical equivalent of an asthmatic who has forgotten his inhaler.
Its a week before I get a chance to sit down and review the problem. There is no way it is a the derailleur. Everything is perfectly set up from the start and the adjustments did not affect the problem one bit. Nor is it the chain length as I check again.
So some happy time putting the taking off the bottom bracket and we are in business. Only we are not - there is still the irritating hiccup, even though the chainline looks near enough perfect by eye. So I do what I probably should have done when I put the front chainring on, I look at the chain itself. What do you know one little stiff link. Rigid and immobile and so unable to bend round the jockey wheel.