..I'll kick in my usual long-winded reply.
Unless its been specifically set up for the whammy bar, a guitar will quickly go out of tune when the bar is used. The strings 'creep' past the nut, and don't return to exact pitch. Several different approaches are taken to correct this.
The most basic is to make a
little more clearance through the grooves in the nut. Another fix is to use a slippery material, like graphite, for the nut. Still others use tiny rollers in the nut, instead of cutting grooves in solid material. All of these techniques attempt to reduce the string detuning by making it easier to return to correct pitch.
The other way to approach the problem is to try to prevent the strings from moving in the first place. This is why a lot of trem-fitted guitars have locking nuts. These are clamps that prevent any string movement at all through the nut, except when the clamp is loosened to permit tuning.
The same creepage problem appears at the bridge, and similar fixes are applied.
A lot of factors affect string bending, but the presence, or absence of a trem bar is not major. The shorter scale length of a Les Paul means that a string doesn't need to be as tight as the same gauge string at the same pitch on a guitar with a longer scale length, like a Stratocaster. (The scale length is the distance from the nut to the bridge saddles). If the string doesn't have as much tension on it, its easier to bend, so the Les Paul wins on that point, but not because it doesn't have a trem bar.
By the way, some Les Pauls
do have tremolo bars, usually made by Bigsby.
Lordathestrings
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