Guitar Tip #55: know your truss rod

Disclaimer: If you do not feel comfortable doing these adjustments on your own, consult a reputable guitar technician in your area to make them for you.

I get a number of hits a day from searches about string buzzes. Although I’ve written about Buzz Feiten, I haven’t written about guitar set up…until now.

The truss rod, what is it? By definition, truss means to support, strengthen, or stiffen. The rod acts a counter tension to the strings. When your guitar is up to tune, the strings want to pull the neck forward. Tightening the truss rod creates tension on the opposite side of the fingerboard, and counters the pull of the strings. Adjusting the t-rod can create a well playing guitar for those who like fast action, or for those with heavy hands who play hard.

There are two types of truss rod.

The first is a long steel rod that is anchored at one end, and threaded at the other. It is installed in the neck permanently, and can be either tightened or loosened. This is a traditional rod hat can be found in most guitars today. Tightening puts tension on the neck causing it to bend backwards, loosening it allows the strings to have more influence on the neck pulling it forward

The second is a 2 way rod. There are a few different versions of this rod, but the gist is that by adjusting the rod, you can force the neck to bend by changing the shape of the truss rod, rather than applying counter tension and creating balance between the strings and the rod.

So how much relief is too much, of not enough for that matter?

The relief (curve) of the neck can affect a lot of aspects of the guitar, playability, action, intonation. If your guitar buzzes when you play, or it looks like your strings are about a mile high at the 12th fret, you may need to have your t-rod adjusted.

Adjusting the rod is as easy as righty-tighty, lefty-loosy. If your strings are high, tighten the truss rod to bring them down. The amount of curve can be seen by fretting at the 1st fret, and at the 20th fret simultaneously the string should hover above the 12th fret about 1/16 to 3/32 of an inch. Any more than this, and the guitar could have some intonation problems. If the string is bottomed out on the middle frets, loosen the t-rod a little at a time until the strings are at the 1/16 -3/32 height is reached.

For the most part, the t-rod sits in a state of stasis. If you’re not changing string gauges, or live in a place with extreme temp and humidity swings, most likely you can set it and forget it.