Submitted by asterism in guitar

What is a truss rod?

A guitar has steel strings (obvi) that create tension (obvi). Now this tension pulls the head of your guitar towards your bridge and creates a bow in the neck. If you hold your guitar out and look at the neck you might even be able to see it bowing. Now there is supposed to be a slight bow (very slight) but if your neck bows too far this can create a couple problems. To counteract these problems there is a steel rod inside your guitar neck that can be adjusted to reverse the bowing effect and keep the neck where it belongs. This is the truss rod.

The problems

If your guitar is bowing outwards (that is the head is moving up towards the body) what happens is that the middle section (think 7-12th frets) is farther away from the strings than your lower or higher frets. Meaning that you have to press harder than normal at those frets just to play the string properly (the higher the string the harder you have to press). If its really bad this can make the guitar extremely difficult to play. The difficulty in playing can lead to a little buzzing at these frets as well as intonation problems too. So if playing your guitar gets more difficult as you go higher up the neck towards the 12th fret you have this problem.

Now picture you have a problem with the guitar bowing the opposite direction. Now your middle section is too close to the strings. What happens here is that horrible buzzing or dead note sound no matter how cleanly you play the note or what you do. I find this is really common on bass strings when it starts to happen. So if you have a string consistently buzzing whenever you play it (especially at lower frets like the first five) you have this problem.

Now if you are a nerd you can also check for proper bowing with a feeler gauge and a capo and the common wisdom is do this twice a year (summer and winter). Personally I just wait until I have one of those problems and then adjust it.

How to adjust the truss rod.

Your going to need an allen wrench for starters second you need to know where it is. I won't cover every location the two most common are at the head of the guitar. If you see a little divet there or if you have a small plastic cover on the head (just above the very first fret) that is where the truss rod is (you just need to remove that cover). Or on Acoustics its typically just inside the sound hole if you look into the hole towards the head. Obviously you stick the allen wrench in the hole. Make sure to get a proper sized one you don't want to strip the screw.

Now this is important

do not turn the truss rod more than 1/4 turn at a time. It can/will break your guitar

If you have the first problem (where the string hieght increases and it gets harder to play as you move towards the 12th fret) you need to tighten (turn clockwise) the allen wrench. You might consider loosening the strings a little because it will tighten the strings. You are aiming for 1/8 to a 1/4 turn.

Likewise if you have the second problem (buzzing open or first five frets especially) then loosen (turn counter clockwise).

After that I would tune the guitar and then let it sit for 24 - 48 hrs. Then see if the problem went away. If the problem is there after 24-48 hrs turn it 1/8 - 1/4 turn again and wait another 24-48 hrs.

This stuff might not apply to you if:

  1. You only play classical guitars. They don't have truss rods (don't need them).

  2. If you are mortified about breaking stuff(its not hard to do but if you overdo it you can break stuff)/ don't know how to use an allen wrench.

3.If you have the cheapest of cheap guitars. (those supposedly don't have adjustable truss rods. But My first guitar was a FirstAct (a cheapo brand) and it had an adjustable one.)

That's all folks. Maybe we talk about action and intonation next?



You must log in or register to comment.

Fool wrote

How to adjust ... rod.
Your going to need ... the head ... if you have a small plastic cover on the head ... (you just need to remove that cover)... just inside the ... hole if you look into the hole towards the head. Obviously you stick the allen wrench in the hole. Make sure to get a proper sized one you ... want to... screw.

What did I just read?


asterism OP wrote

Just wait for one of my next posts. We're going to be talking about action, nuts, saddles, and g strings.


asterism OP wrote

I was laughing a bit when I typed it up too but I couldn't really figure out alternative verbage either.


Fool wrote

guitar has steel strings (obvi)

Steel strings? Like I'd believe that, next you'll say that you can have Nylon strings.

I'm not falling for your lefty bullshit, words have meanings and string isn't metal.


asterism OP wrote

Wait till I tell you about gut strings. But also ew gross gut strings.


lentils wrote

Maybe we talk about action and intonation next?

Yes please :)


asterism OP wrote (edited )

Just so you know the correct and proper way to do this.

You need a couple tools. A capo and a feeler guage (basically precision metal slabs for measuring). you put the capo at the first fret. Then you press down the very last fret on the low E string. Then you take your feeler guage and measure the distance between the sixth or seventh fret (the actual fret the metal thing) and the bottom of the low E string. It should measure around.015” – .030” for an acoustic and .010” – .012”. for an electirc. You might be able to get a specific number from the manufacturers website.

If your measurement is greater you need to tighten the truss rod. If it is smaller you need to loosen it.

And there you have it. Doing things the right way instead of eyeballing it like me.