Wednesday, October 14, 2009

Truss Rod Adjustment Guide

The images below are exaggerated for Illustration purposes.

Neck Bow

Up-Bow indicates too much relief. The truss rod is too loose.

Back-Bow indicates not enough relief. The truss is too tight.


Relief can be measured by fretting the E string at the 1st and last fret simultaneously. I use a capo for the 1st fret and my finger for the last fret.

Then take a feeler gauge and measure the distance between the bottom of the E string and the top of the 9th fret.

A typical measurement is .3mm to .5mm at the ninth fret.

Truss Rod Adjustment


The photo above shows the truss rod adjustment point. It is typically located behind a plastic cover with 3 screws. Occasionally you will find it at the opposite end of the neck.

Some are an allen wrench type adjustment (pictured), while others are a nut type adjustment. The nut type requires a special wrench.

To correct back-bow loosen (counter clockwise) the truss rod. To correct up-bow tighten (clockwise) the truss rod.

Truss rod adjustments should be made in 1/4 - 1/2 revolution increments. Adjust a 1/4 to 1/2 a turn and let the guitar sit. It takes some time for the neck to react to the adjustments, sometimes as long as 24 hrs. I usually figure an hour.

If the truss rod is extremely difficult to tighten or loosen STOP and visit a qualified tech.

The truss will often make the neck creak to some degree as it is being adjusted. This is normal.

You must use common sense.

Adjust until relief measures approximately .3 to .5mm.

Damage can occur if common sense and good judgment are not observed. If in doubt, STOP and take it to a tech.

From Ibanez


All guitar necks are subject to great stress as a result of string tension, humidity
or changes in climactic conditions. Occasionally, there are times when the neck
may need adjustment.

The truss rod is adjustable at the headstock using as allen wrench or an adjustment wrench.

Note: This adjustment should be performed periodically and only by qualified repair personnel.
Over adjustment can result in damage to the instrument and will no be covered under warranty.

Link to Source


All guitarist should be able to make these adjustments themselves. If not now...then in time.

I hope this helps some people. Feel free to point out any errors and make additions.

Source : S-man @ The Guitar Matrix -

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1 comment:

CtGuy1955 said...

I was wondering about a neck that is dead straight and the nut for the trussrod is loose. If I put 12's on it instead of 10's, Ive heard that some luthiers use heat rods and some use steam to get the wood on a new guitar to buy some relief ?

I have a pellet stove that puts out some nice heat, but not too hot, would it be ok to leave it in front of heat for a 4-5 hours or what do you think ??? I have some buzz and I already raised up my bridge. Thanks for any info !