Originally Posted by
dannwilliams
Mine failed because something lodged in one of the jockey wheels on the rear derailleur, I was going uphill loaded, and I forced the pedals when it locked up. If I had stopped, and checked for the problem, I would not have broken the chain. But I did not, and broke the chain. I repaired roadside with no difficulty. Now I carry a spare chain, not much weight penalty in the total perspective: rider 195, bike 30+, gear 40+, spare chain a few ounces.
Why not carry just a couple links and a chain tool? Most 9 speed chains weigh between 10 and 11 ounces. That isn't exactly insignificant. A few links and my chain tool weigh less than half of that.
I have never seen a chain suddenly fail in a way the just replacing or just eliminating the damaged link would not suffice to get you going again.