Im fixing some bikes for a friends kids. One of the spokes in the rear wheel is broken. So how do i measure up for a replacement?
It seems logical that i measure from the elbow nipple on a same side spoke. Then add an amount to account for threading into the nipple. Is that 12mm for a normal brass nipple? If this is incorrect how should i do it?
Thanks
Ian

I think that would work (mind, IANAWB)
Suppose the ideal would be to take out another spoke on same side but, meh
Presumably the threaded end of the broken spoke’s not still there to measure ? If it was, I bet you could loosen a spoke enough to show the bottom of the threads and measure that “accurately” and just add on the 12mm

Where did the spoke break? Any wheel with a broken spoke most be at least slightly suspect unless there is already a good explanation. If there nipple sheared then the length is suspect anyway. If it failed elsewhere then stress relief is suspect and should be done thoroughly.

The thread length is normally around 10mm, not 12mm (the length of a normal nipple). But you cannot be sure without checking, it could be as short as 8mm. You should take out a spoke and measure it properly, at least fully unthreaded from the nipple and at that point you might as well take it out of the wheel. You can also check that the rest are well seated into the head of the nipples.

If you measure from the bottom of the spoke hole on the hub flange or the inside bend of the spoke to the bottom the nipple then add 12mm you should have a usable spoke length give or take a mili, a normal 12mm nip in an average rim will have about 7 or 8mm showing any longer might mean its a 14mm nipple.

It’s not hard to take a single spoke out to get an exact measurement… But then you ask, is this spoke even the right length?

If you can see to the base of the thread, and you can accurately measure from the bend to there, you can just add 10mm and you’ll get a good result. Measuring it accurately isn’t that easy tbf but, you can improve your odds by measuring a bunch of spokes then averaging it. It doesn’t have to be exactly right after all.