Peculiar wheel size 559x17??

[MichaelW2]

The secret to not screwing up your wheel with a spoke key:
Ensure that the required spoke nipes actually turn. If they are siezed in place, a bit of wd40 and a day or two helps. Clean it off braking surfaces.
Use the spoke key1/4 turn at a time. No more.

 

[andrew_s]

Use the spoke key1/4 turn at a time. No more.

If the spokes are under tension, as they should be in a working wheel, they will twist a fair amount before the nipple turns on the spoke, so in order to turn the nipple 1/4 turn, you may have to turn the spoke key 3/4 turn, then 1/2 turn back to unwind the twist. Judging/feeling the amount of over-turn required is something that comes with practice.
Any residual twist should be released by lying the wheel on its side, and pushing down reasonable hard on opposite sides of the rim, moving round a bit and repeating until you've pushed down on the whole rim, turn the wheel over and repeat, then check the wheel trueness again.

 

[livpoksoc]

So just seeking some clarity - how do I establish which spoke (group of 3) to adjust? Is it the ones that contact the brake pad when spinning? Because my wheel is bent so much thst it rubs the brakes without them being pulled on.

 

[figbat]

If the spokes are under tension, as they should be in a working wheel, they will twist a fair amount before the nipple turns on the spoke, so in order to turn the nipple 1/4 turn, you may have to turn the spoke key 3/4 turn, then 1/2 turn back to unwind the twist. Judging/feeling the amount of over-turn required is something that comes with practice.
Any residual twist should be released by lying the wheel on its side, and pushing down reasonable hard on opposite sides of the rim, moving round a bit and repeating until you've pushed down on the whole rim, turn the wheel over and repeat, then check the wheel trueness again.

A small bit of tape folded around the spoke like a flag can help determine if and how much a spoke is twisting.

 

[livpoksoc]

Actually found the source spoke...it's a broken one. So...is that an easy repair? Assume it's going to be something like
1. Remove tyre, inner tube & rim tape.
2. Remove broken spoke
3. Replace broken spoke.
4. Put all back together and adjust tension in remaining spokes?

I take it the spokes should be a standard size based on the rim diameter?

 

[andrew_s]

Spoke length depends on wheel size, rim profile, and number of crossings. For rear wheels and disc brakes, the left and right spokes are also different.
The length is from the very end of the threaded section to the inside of the j-bend.

It's simplest to measure an existing spoke. Most accurate is to remove and measure an existing spoke from the same side of the wheel.
Otherwise...
If the head broke off (the normal break), measuring the broken spoke end to end will be close enough, otherwise you can measure hub to rim face and add 2 mm to allow for what's hidden in the nipple.

If it's just the one spoke, and you haven't fiddled with the others, it's remove and replace the spoke, and bring it up to the same tension as those two along from it (i.e the next spokes going to the same hub flange).
If the wheel isn't decently straight after, it's a matter of adjusting other spokes until it is. Tightening a spoke moves the rim towards the hub flange that the spoke is attached to. Don't do more than half a turn in one go.
Loose spokes tend to fail more easily than extra tight ones, so I generally adjust only by tightening, unless I believe they are getting too tight.

When you are done, go round the wheel squeezing pairs of spokes together at mid-length as hard as you can by hand. You may break another spoke or two, but anything that breaks was already cracked and due to fail fairly soon, and the squeezing (aka "stress relieving") makes undamaged spokes less likely to fail.

 

[livpoksoc]

Spoke length depends on wheel size, rim profile, and number of crossings. For rear wheels and disc brakes, the left and right spokes are also different.
The length is from the very end of the threaded section to the inside of the j-bend.

It's simplest to measure an existing spoke. Most accurate is to remove and measure an existing spoke from the same side of the wheel.
Otherwise...
If the head broke off (the normal break), measuring the broken spoke end to end will be close enough, otherwise you can measure hub to rim face and add 2 mm to allow for what's hidden in the nipple.

If it's just the one spoke, and you haven't fiddled with the others, it's remove and replace the spoke, and bring it up to the same tension as those two along from it (i.e the next spokes going to the same hub flange).
If the wheel isn't decently straight after, it's a matter of adjusting other spokes until it is. Tightening a spoke moves the rim towards the hub flange that the spoke is attached to. Don't do more than half a turn in one go.
Loose spokes tend to fail more easily than extra tight ones, so I generally adjust only by tightening, unless I believe they are getting too tight.

When you are done, go round the wheel squeezing pairs of spokes together at mid-length as hard as you can by hand. You may break another spoke or two, but anything that breaks was already cracked and due to fail fairly soon, and the squeezing (aka "stress relieving") makes undamaged spokes less likely to fail.

Thanks - yes it has snapped at the nipple, so will measure from there. Am I going to have to remove the rim tape to do this, or can a single spoke be replaced without doing that?

 

[Ajax Bay]

Edit: If you can unscrew the broken spoke, you can leave the nipple in situ (so no need to remove rim tape). Check how many turns till the first bit of thread shows (and note down). Get the right length spoke and just a straight replace. Keep turning the nipple until the thread on the new spoke disappears and then (check notes ?2 more full turns). Then true the wheel.

 

[figbat]

If it has broken at the nipple with none left to grip then the tyre and rim tape will have to come off and you’ll need a new nipple. If you can unscrew the broken stub from the nipple then it can stay put.

 

[livpoksoc]

Looks like a clean break at the nipple. Sigh. Ah well, good to practice on this bike.

 

[Ajax Bay]

Note that if it's broken at the nipple then likely it'll be at the first thread (acting as a stress riser). In that case, if your measurement of (another) spoke falls between lengths, go up not down. Also consider carefully examining the other spokes on that side of the wheel (?non-drive side rear wheel?) to check that no sign of thread is visible beneath the nipple.

If the head broke off (the normal break), measuring the broken spoke end to end will be close enough, otherwise you can measure hub to rim face and add 2 mm to allow for what's hidden in the nipple.

Agree first part but using the second lacks assurance: rims are different: image from the late Sheldon Brown's site.