Had a couple of broken spokes in the past. On both occasions the wheel tension seemed fine. Why do they break? That 1 spoke on two different wheels.

Dunno, but limping back fifteen miles on the road bike this afternoon was no fun when one pinged after a pothole. Wheel went quite pringly, but I managed to get it straight enough to just turn with the brake block taken out at the back. Carrying a spare wouldn't have helped much as it was rear driveside, and I'm not going to carry cassette tool, chainwhip and big spanner under my saddle on the roadie. First time I've done one in ages.

good grief 🙄

Heh. By contrast I broke a spoke at fort william on my 2nd run of the day, didn't have much choice but to carry on and do another 6 runs down the red then the bottom of the wc downhill course, ping ping ping Quite tough wheels apparently, it trued straight back up with a new spoke and is still fine now.

In this case the question of "Why did it break" is answered "Because you landed a drop half sideways directly onto a huge rock, you tool".

could you not have carried a spoke tool and just adjusted the remaining spokes to move the rim across?

To the OP. Spokes break either because wheels are built badly or because they get hammered past the spokes strength. Depends where they break obviously too. if they keep breaking at the elbw you might have a sharp burr on the hub, if they keep stripping nipple threads they might need re-tensioning.

Retensioned an old old crap wheel on an old old heap of junk for a house mate once, wheel was well out of shape to begin with…within the first 20ft of him riding, about half the spokes snapped… thought it was worth a try at the time.