A friend bought a second hand bike and I said I’d give it a bit of a once over to check its all ok. Generally it’s in good nick apart from the back wheel which has some really loose spoke tension all over but doesn’t seem particularly out of true.

I’m happy truing wheels up but this is a bit all over the place and feels like even the tighter spokes are too loose. What’s the best way to go about this without risking making things worse? Or is this an occasion to defer to someone with a jig and more skillz?
thanks

If you’re happy truing wheels take tyre off and reinstall wheel then wrap some tape across the stays just above the rim and pen mark the rim position on the tape or attach two strips of card to the tape either side of the rim then just tighten the nipples 1/8 of a turn at a time starting at the valve. A few goes around will slowly tension and should keep it true. Truing and tightening loose spokes is basically the same skill.

I’d loosen all the spokes and start again on evening up the tension around the wheel, could be a dodgy rim causing this, or damage to spokes/nipples. How is the wheel radially?

Yeah, I misread this one, not fully awake, thought all the spokes were loose, argee is right.

Maybe see if you can borrow a spike tension meter as they’re quite handy (but not essential). If it were me I think I’d also loosen all the spokes off to the same tension (ish) then go round and add a quarter turn tension on each spoke at a time until there’s some reasonable tension in the wheel (but not finished tension). I’d then work on getting the wheel pretty true and then go round with the tension meter and see where tensions are.

I’ve found it’s near impossible for them to have exactly the same tension and the wheel be true but it’s a compromise to get them as even as you can whilst having a straight wheel.

Loosen off, start again

Probably easiest to slacken them all off to some observable point, either threads just showing below the nipple or, if you can remove the rim tape, flush with the bottom of the nipple slot.

The alternative is to true and try to bring all the loose spokes up to reasonable tension. That is in any pair you would tighten the looser spoke until it is starting to pull against its opposite. If both of a pair are loose, tighten both until in the ballpark of the rest.

A clothes peg on the stay or bridge makes an excellent truing indicator. Flip the wheel to check dish.