adjustment help

Discussion in 'Hardware, Setup & Repair [BG]' started by mike phillips, Dec 29, 2005.

  1. how do you know when the truss rod needs adjusted? how is it adjusted? when the truss rod is adjusted does anything need done to the bridge? thanks, mike
  2. Kronos


    Dec 28, 2005
    Philadelphia, PA
    Simple question with a long answer.

    When you pluck a string on your bass, the string vibrates in an elliptical pattern. If you have a neck that's as straight as an arrow and low action, you're going to get fret buzz no matter what you do.

    Now, most modern instruments with truss rods are set up with a certain amount of relief. "Relief" is a slight bow in the neck to accomodate the movement of the string.

    Problem with this is sometimes the bow is too much, or too little. That's where the truss rod comes in.

    A single action truss rod slowly straightens the neck, thus giving you lower action and less relief. Once this is done, it can't be reversed.

    Double action truss rods, however, can be adjusted both ways, to either give you more relief, or less.

    So, to answer your question, truss rod adjustment needs several factors taken into account, such as whether or not you have trouble setting the intonation no matter where you put the bridge saddles, or if you have very low action around the upper and lower frets, but high action in the middle, etc. I hope this helps you out.
  3. bikeplate

    bikeplate Supporting Member

    Jun 7, 2001
    Upstate NY

    Pretty simple. Look down the neck. If its bowed either way, you need to adjust your neck. Backbow, clockwise. Frontbow, contourclockwise I think. LOL!!! Usually a quarter turn does the trick. Once you get it close to straight, you can set the action the way u like

  4. thank you for your reply. it is a big help.
  5. Is this true? I mean if I loosen the truss rod tension, the neck will bow again (increasing relief), its not locked in any way right? :eyebrow:
  6. You're correct. I think Kronos misworded that part. The single action truss "pulls" only one way (when you tighten the nut), but turning the nut the other way "relaxes" it, taking some of the tension off the neck. The string tension then pulls the neck forward and you have forward bow (or relief).

    The double-action truss works 2 ways. It pulls when you tighten it, but will also pull the opposite way if you loosen it. This is supposedly for backbowed necks that need help in the other direction? I've never really understood that part.
    But for practical purposes, they both do the same job.

    Mike Phillips: Read the sticky post in this section, and familiarize yourself with the Gary Willis setup site. It makes much more sense after that.