Doing somewhat of an odd tuning on a 4, rather than BEAD, doing what I guess would be Drop-B tuning, BF#BE. I compared tension ratings on d'addario's site between strings ive used and know how the tension feels, and what I'm thinking of using for this tuning. I settled on
these because the tension of the strings I'll be tuning up from their standard are around 10lbs. of tension less than the flats I have on my seldom-played 5 string. I know the B will be 'floppier' than the others, but the .135 B only adds around a pound of tension and I'd have to buy a separate string.
I also have to mention that the neck of the bass these are going on is rather strong, with 45-105 strings in EADG i had to really tighten my truss rod to get a slight bow, so I'm not concerned about the neck. The bridge is also string-through-body so no worries there.
I'm mostly concerned that even though these are low tension light gauge strings, could they possibly break under the strain of tuning each up a step farther than they are intended? This is one of the things about strings I'm never sure about.