When does string tension become dangerous?
 

I've been using some heavy string gauges for a while now : .045 - .065 - .085 - .110 - .140.

I can't really say it affects the bass neck more, then the standard gauge string that was on first : .045 - .065 - .080 - .100 - .130. I check the neck about three times a week and tweek it when I think I have to.

But when does string tension becomes dangerous for the neck? Is it is you have a thin neck like an Ibanez SoundGear with heavy string gauges or if you up tune strings?

Tuning up will definitely cause some problems, mainly broken strings. Do not tune up.

Nothing wrong with those gauges. It's at the high end of the spectrum, but still normal.

There is nothing unreasonable about those gauges. It should be fine. A tweak of the truss rod, yes, but nothing out of the ordinary.

I think that the string will probably break before it becomes unsafe for the neck.

I'm not sure I'd rely on this advice. I can envision tuning a bass up a step and the strings would be far from breaking, but the increased tension from four up-tuned strings could adversely affect a bass neck.

i have to think that as long as the neck is adjusted to be straight there's no problem.

the danger comes from a neck with a big upbow (regardless of string gauge) that's left that way for a long time; eventually the wood gets "used to" that shape and won't want to straighten out again.

I tend to stay below 50 pounds of tension per string.