I bought some new strings for my bass and was informed that 40 is what you find on most basses when they come out of the factory. I restrung my bass today and the stock strings are actually thicker than the 40s I bought. I'm guessing they're 45 gauge. Having been a guitar player I know that you may need to adjust the truss rod after a change of string gauge. Am I being correct assuming that the lighter strings exert less pull which leads to a more convex bow which in turn means that a loosening of the truss rod is in order?
Chances are that you won't need to touch the truss rod. Assuming the pitch is the same as it was previously, the new strings are only 10% lighter, so the tension is down by that 10%. If the neck was fine before, it'll probably be fine now.If there is a difference then yes, the truss rod would be loosened, but only by maybe half a turn. The other thing to be aware of is the intonation which as a guitarist, you'll already be aware - the saddles may (or may not) need slight adjustment.And - you may be able to lower the action slightly more than it was with heavier strings.