Before I start….

Road wheel, virtually new, used for 250 miles, including sprints around 1000w. All good. Then all of a sudden looses tension on nds and rubs on brake at less than 500w.

Checked with tension meter, nds virtually zero on nds. Tensioned back up to spec, and found the wheel was now massively out of dish and touched the chainstay on the nds. Tension on ds is at spec and virtually untouched other than to true as part of tensioning the nds.

Confused as to why / how this could have happened. Kind of assumed that if one side loosened, re tightening it to where is was would have left me with a wheel exactly as before rather than completely out of dish.

I take it the only thing for it is to completely slack everything off and start again?

I take it the only thing for it is to completely slack everything off and start again?

It’s what I’d do, though I’m no way an expert

You prob could get it back REALLY slowly by just tightening the slack side a very little each time, and maybe doing alternating sides (even quarters) of the rim. Otherwise I’d guess the tight side would **** it all up

Yep, slack off and start again. What wheel?

Zip 404 so not overly impressed. I’ll give it a go one night and if I can’t Sort it back to where I bought it from….

It wasn’t only 1 side losing tension, both did.

If it is properly true up/down, and side to side, there’s not much point in slackening everything off and starting again, just loosen the offending side a touch, and tighten the other a touch, gradually working it until it’s central, true, and tight.

Cynical, on my park tension meter nds was 0 to 5 ds (should be 8) was 12-14(should be 12.5) The flex was only occurred on a hard left downstroke. Right downstroke did not cause it to rub. Calipers were setup correctly. So I am pretty certain it was only the nds unless I really don’t understand how wheels work!

Wheel was perfectly dished, true and tensioned when I first got it (I check these things now). No potholes involved. Just tightening the nds back up to 8 pulled it way out of dish. Odd.

Zipp notoriously underbuilt – they have to achieve the low weight somehow! I’d slacken everything off and start again – check everything carefully, particularly around the hub flange as they’re prone to cracking

You don’t really understand how wheels work…the DS lost tension, but didn’t go as slack.

Al’s right, but grumpy

it’s possible that the drive side stayed all “screwed in” but they’d still have lost tension as the other side slackened – they oppose each other, after all. This also would’ve meant the rim moving out of centre between the stays – might explain the one sided rubbing.

If the rim stayed central, then both sides must have lost tension

DS spokes are under more tension, unless you have an offset wheel which definitely won’t be the case on a road bike. Because of that, they always feel more taut (because they are)

Still not sure I get it, understand about spokes opposing but how come the ds spokes are still showing the same tension on the tension meter if they have gone slack?

Anyways it sounds like the answer is to detension and start over. checked for cracks, none, and the zips aren’t really that light at around 1650 virtually the same as my carbones.

Still not sure I get it, understand about spokes opposing but how come the ds spokes are still showing the same tension on the tension meter if they have gone slack?

Built a few wheels now and had to have a good think about this when tensioning.

Came to the conclusion that NDS and DS tension is all related. The tension in an individual spoke is created by the pull of the rim, and this is a function of the tension in all of the spokes.

In your case for the NDS to lose all tension and the DS to have the same tension, something must have happened to both sides. I guess the tension might still be high in the DS side as you now have the rim pulling on half the number of spokes, so it’s still high despite having lost tension.

I’m sure someone more knowledgable will be along in a minute to tell me that’s rubbish. There’s no doubt a Sheldon Brown article on it somewhere 🙂