For any owner of a vehicle with wire wheels, the "tone" test is something one should perform about once a year. You take a small spanner or similar metal item of light but sturdy type, and tap/knock on each spoke, if any give off a tone that sounds hollow or too deep, it needs to be tightened to sound similar to the rest.
This only works if your wheel is already true, and most of the spokes are good. If too many are out, then tightening must be done equal to them all, one turn at a time so not to warp the rim. Even this is not likely to be 100 % successful. So check early and ofthen, to solve problems while they are small.
The best way is to use a spoke nipple torque wrench, this will show you the torque of every spoke, time consuming, but the best method.
