Changed my strings - now my neck is different

[Johnny5]

Hey guys, here's the story.
The strings that originally came with my Fender Highway 1 P Bass needed a changing (rounds) and I'm assuming that they were 45's because that's usually the case. I really like the feel and pop of flats so I bought a set of 45's and threw them on my bass. The first thing I noticed was that the action was A LOT higher for some reason. What could've gone wrong? I've changed bass strings tons of times but nothing like this has ever happened, but this is my first change from rounds to flats. Now my truss rod needs adjusting and it's proving to be a huge pain to get it back to the way it was.

[Tony G]

My guess is that the flats have a much higher tension than the usual round wound strings your used to use, and is putting additional stress on your neck causing it to bow forward a bit. Just adjust the truss rod to get it back to where you like it. It isn't to hard, but I suggest reading up on how to do it if you've never done it before.