I use a Topeak Hexus 2 or a Topeak Mini 18, I like the latter because of its small size, but prefer the former as its slightly lighter and the chain tool is larger plus I get another tyre lever in case I break one. Otherwise their both good. One criteria I have though is, I will do all jobs initially at home using a new multi tool so that I am confident that it will not break or bend and is up to doing the job out on the road.
I just wish some manufacturer though would create a multitool which you can strip down to remove all the bits that do not fit your bike. Half of whats on my multi tools fit nothing on my bikes.
Before multitools came out, for years, I just carried a small nut and a two inch nail and if my chain broke, I would just find a rock, brick etc and put the link over the nut and knock the pin partially out, split the chain, make the repair and then knock the pin back in. Worked a treat too and is easier than you think.
Alternativly, I would tie the broken ends of the chain together, fit the broken part of the chain at the bottom where there was no strain on it and just half pedal backwards and forwards all the way home. Simple and effective on the flat and low hills but doubt you could keep the speed up on steep hills as I was lucky never to encounter them in such a circumstance These days a zip tie would be ideal for doing a repair like this.
Used to get a lot of broken chains in the old days thinking about it....but there again parts were rode till destruction before you renewed anything
My Hexus stays on the road bike as it is more compact to carry than the individual tools that would do the same job and doesn't rattle.
