Changing the strings on a classical guitar differs from changing steel strings, because nylon strings are attached by tying them both at the bridge and at the tuning machine. This LG Guitar Guide article walks through the change step by step, so the strings stay in place, the instrument is not damaged and the tuning settles more quickly.
Preparation
Set aside a calm moment and a clean, flat surface. It is best to change the strings one at a time, so the neck tension does not change all at once and the instrument stays balanced. Keep the new string set, a string cutter or scissors and a tuner within reach. While one string is off at a time, you can also wipe the fretboard and bridge clean.
Removing the old strings
Loosen the string to be changed at the tuning machine until it is slack, then detach it from both the bridge and the machine. Do not cut the string while it is under tension, because a sudden release of tension is not good for the instrument. Nylon strings do not rust like steel strings, but an old string loses its brightness and intonation, so the whole set is usually best changed at once.
Tying the string at the bridge
Pass the string through the hole in the bridge so that a short length remains behind. Wrap this length over the string itself and tuck it under the knot behind the rear edge of the bridge, typically with two or three turns on the thin strings and at least one on the thick bass strings. A correctly made knot locks itself as the string is tightened. Make sure the loop of the knot stays behind the rear edge of the bridge and does not press on the finish, so the top is not damaged.
Tying the string at the tuning machine
Pass the other end of the string through the hole in the tuning post, leave a little slack and lock the string by winding the end around the post so that the string goes under and over itself. This keeps the string from slipping. As a guide, wind the thin strings a few turns around the post and the thick bass strings slightly fewer, because too many turns on a thick string fills the post. Wind so that the string runs neatly and does not overlap untidily.
Stretching and tuning
Nylon strings stretch a great deal during the first hours and days, so the tuning keeps dropping at first. Tighten the string close to correct pitch and gently pull it with your fingers at several points to help it stretch, then retune. Repeat this until the tuning begins to hold. Full settling usually takes a few days, and during this time the instrument often needs retuning. Patience is rewarded: hasty cutting or over-tightening can break a string or leave the knot loose.
Common mistakes
The most common mistake is leaving the knot loose, so the string slips and the tuning fails repeatedly. Another frequent mistake is winding the thick bass strings too many times around the tuning post, so the post fills up and the string overlaps untidily. A third is changing all the strings at once, releasing the neck tension entirely in an instant. Avoiding these makes the change go smoothly and the instrument hold its tuning sooner. Remember too that different string sets are tensioned differently, and when moving to a new set the tuning and playability may feel slightly different.
Finishing up
Once the tuning has settled, trim the extra string ends neatly. Regular string changes keep the instrument's sound bright and its intonation accurate. If you want to know when a change is due and how else to care for the instrument, read our other guides as well.
