I know some classical guitars absolutely definitely can't handle extra-hard tension strings because they can cause the bridge to break or the neck to bend, so only guitars specifically designed for extra-hard tension strings should use such strings. I understand that one of those design modifications is the inclusion of a truss rod, even though classical guitars normally do not need one.
One example of extra-hard tension strings is Daddario's EJ44LP, shown below (90.8 lbs total):
But what about hard tension strings? Are they safe for your average classical guitar without a truss rod? I've checked some spec sheets, like Yamaha's C40II or CG Series, and the "strings" spec seems to be about the strings that come included with the guitar, and not the recommended tension. Other than that, there doesn't seem to be other specs related to string tension.
One example of hard tension strings is Daddarios EJ46LP, shown below (84.9 lbs total):
For simplicity's sake, let's assume that the "average classical guitar without truss rod" has the specs of Yamaha's C40 - C80 series. And also assume standard tuning, and 85 lbs total tension for high tension strings. Would high tension strings be safe on a classical guitar similar to those?
For reference I'm including Daddario's EJ45LP "normal" or "medium" tension specs below (82.7 lbs total):
So, how does one know if high tension strings are safe for a specific guitar? Medium tension strings are said to be safe for any classical guitar, but can the same be said about high tension strings? Which specs should one look for?
Are hard tension strings generally safe for classical guitars that don't have a truss rod?
