Hi! Last year I got an acoustic guitar for Christmas, and recently i've noticed the neck has started to have a back bow. The place to access the truss rod is inside of the guitar (is it called the heel?). So do I have to take off all of the strings to adjust it, or should I just tune it really low?
The truss rod need loosening, and that will hopefuly restore some neck relief. I generally just leave the guitar strung up and in tune, and poke the hex wrench between the strings. This has the advantage of allowing me to see how much change has occurred. I did one a couple of days ago - I had to use the long end of the wrench, and put a piece of brass tube about 3"long over the short end to get more leverage.
Tony Done

Yeah, I suppose you could call that the "heel". As far as changing the tuning goes.

To get a "back bow" out, leave the tuning where it is. The string tension will assist that adjustment, pulling the neck, (or perhaps more accurately the top nut), "forward" toward the bridge. In other words, the string tension working with you

Now, if you're trying to take "relief out", then you should tune down, because the string tension is working against you.

As long as we're both clear that you're only going to move the adjustment 1/4, to at most 1/2 turn at a sitting, you should be golden.

Necks often change their relief a bit when the seasons change.
Last edited by Captaincranky at Oct 21, 2016,