Rule #1, Cheap strings and tremolos don't mix.
Rule #2, If in doubt, read rule #1. You have a tremolo now, its time to get tremolo strings.
Let's face it... guitar players are notorious for buying the cheapest strings. Its just our impoverished nature I guess. But the truth is most strings should be changed every 10 days or less, if not daily for the best tone. There is a reason the pros change their strings before each gig. It's because strings sound the best for only a short time and then, ever so imperceptibly, they degenerate. I know deep down you all go with this philosophy, but hey, there's that cost issue rearing its ugly head again. So for the above average Kahler abuser like me.. (I play trem-hard at least 2 hrs a day, every day), I find that I need to change my strings about every 10 days otherwise they start to go out of tune a lot.
Just imagine the world of a tremolo string for a second... Put yourself in the shoes of a tremolo string as you get stretched, slackened, plucked, pulled, ripped, warbled and stretched again ...time after time, day after day. It wont take long before you become sloppy and lose your elasticity and vibe too. Same with a string. That's why tremolo players must use tremolo strings and change them more often than any other type of players. I know this from experience.
Tremolos are unique and can set you apart from the rest...
Remember tremolo strings take allot of abuse. The key word here is "TREMOLO STRINGS". Tremolo or reinforced strings have better build quality, pliability and response than others strings made for fixed bridges. They usually cost more too. Look at your string pack and see if it says " TREMOLO STRINGS" or "REINFORCED" Not all strings are meant for tremolos. And at the same time.., not all good tremolo strings will say " TREMOLO STRINGS" or "REINFORCED" on them either. I do not recommend Ernie Ball strings of any type. I have had so many complaints of EB's strings going out of tune (flat/sharp) that it was obvious something was wrong.
Here is a short list of the strings I personally recommend for Kahler's: Roto Sounds, Elixir, DR, SIT Power Wounds and GHS Boomers. I am sure there are other brands out there I am unfamiliar with, so if you find a set that holds up well and you would recommend, please let me know. I feel it is worth the mention.
The G string and why its so temperamental with a tremolo.
G strings usually give tremolo players the most tuning issues..why? There are 2 reasons for this keeping in mind you may experience both issues:
#1 The knots that tie strings around the ball end can be the culprit. You need a good knot. Think again of the G string. It has smooth wire and is the thickest of all the smooth, non wound strings. It is simply harder to get a tight knot when the wire is thick and smooth. The knot sometimes does not get synched down tight enough at the factory and can actually slip in and out (flat/sharp) of its knot. Its kind of like a hangman's noose. That's why in the old days before tremolo strings came around, people would solder the winding. Today it's still necessary to do this for some cheaper strings or if one doesn't hold, so this 80's era method still lives on....
#2 The "2 string per clamp plate" string locks and locknuts. This problem is most noticeable on string bends because in order for it to return to pitch you have to dive all the way and release it. This lets all the tension "force re-seat" itself through the dragging problem areas like a loose string lock. Also the small E string can have the same issues as the G string because of the size differential. The string lock usually has 3 clamp plates that the string pairs pass thru to get clamped. The E/A pair is first followed by the D/G pair in the middle window and finally the smaller B/E strings in the last window. Most issues are in the middle clamping window that the D (wound) and G (smooth) strings pass thru to get clamped. There is a reason for this. The D is wider and has a winding that grips well while the G is just the opposite. The G strings are thinner than the D, smooth and more slick too. So when the clamping is applied, it is applied in a flat equal plane so the fatter string gets to feel the squish first. In order to fully clamp a string you must physically smash it flat. So as you tighten the clamp, the key will get harder to turn until at some point you feel it is tight enough and stop. But in actuality the D string is the only one with enough clamping power to hold. The G string at this point is only snug, NOT tight. So what happens? It slips back (with a string bend) and forth (when you dive) and never stop at center. The same goes for the B/E pair. The E slips because it is not as tight as the wider B string. The cure is simple... Crank the string lock Allen head more and/or lower or clean the rollers.
Generally: Also saddle rollers can cause drag if they are set too high. When a roller is very high there is more pressure from the string exerted on the roller in excess of 30 - 60 pounds, depending on the string and therefore more friction between the roller and its axle pin. This friction is often the cause of which is that the strings tend to stay flat when the arm is pushed down and released and the strings tend to sharp when the arm is pulled up and released. High or even stuck rollers can be the cause of string breakage because of the increased angle of the bend in the string. This breakage will occur at the roller. Visually look at the rollers from the side of the guitar. Do they appear to be set high? The optimum roller height for tuning stability is approximately 9:15 o'clock. Set them correctly if they are too high.