At The Rim
The rim end of the spoke has a short threaded section. The threaded section fits through a hole in the rim and a spoke nipple is screwed down the thread to hold the spoke in position. A spoke nipple has slot so it can be screwed onto the spoke with a screwdriver. As the nipple moves towards the hub the tension on its spoke increases.
Wheel Spoke Key
wheel spoke nipples have square flats so they can turned from under the rim with a spoke key. The key must fit the nipples exactly – there are different sizes – or the key will slip and the flats will get worn away. The spoke nipple is turned anti-clockwise to tighten the spoke. The thread is a regular right-hand type but the spoke key is turning the nipple from ‘underneath’ to screw it along the spoke towards the hub.
If the nipples won’t turn on the wheel spokes, turning the nipples will twist and break the spokes. If the nipples have bonded to the spokes by corrosion you can try removing the tyre, tube and rim-tape and soaking the nipples with dismantling lubricant to unfreeze them. If they won’t come unstuck you may need to scrap the wheel or rebuild it with new spokes – and if necessary a new rim – if the hub of is in good condition. If the nipples are frozen you’ll have to cut the old spokes with metal croppers. If you have to soak the nipples make sure you degrease and rinse the rim carefully before you replace the rim-tape, tyre and tube.
Four Issues Step 5 A good spoked wheel… … has equal spoke tension – or both sides are equal if the wheel is asymmetrically dished. …is centred – the dishing is correct. …is a round circle. …is a flat disc. Work to correct one problem at a time. Start with the worst problem and when that’s improved or corrected progress to the new ‘worst’.
Think Before Each Step
Spend time making a careful diagnosis. Once you’ve decided which spokes to adjust be systematic. You can even put tape on the spokes and number them so you know which is which. If you think carefully before you act you can reverse what you did if you go too far. Spread the load of any adjustments over groups of spokes turning those in the middle more and those at the beginning and end of a misaligned section less.
Stress The Spokes
Between each round of adjustment and re-diagnosis stress the wheel spokes using the procedure checking spoke tension and squeezing hard. This releases any twisting forces trapped in the spokes. If you don’t do this the forces will be released the first time the bike is ridden and the wheel may go out of true straight away. This stressing process is the main difference between a hand-built wheel and one built by a machine.
If you make big adjustments to spoke tension check the ends of the spokes haven’t been pulled up high enough to risk puncturing the tube. If the spokes are high enough to push on the tube remove the rim tape, file them down them then replace the rim tape.