Well, damn. I have gotten so much great information from lurking on these forums as I got into cycling in the last 8 months. Such a wonderful new part of my life. I was planning for my first post to be a helpful "give back" sort of post, not a "help me." But so it goes, as Vonnegut says.
My new bike is a 2011 Jamis Coda. I know it's a lower-end machine, but I've been enjoying it a lot. Previously I was riding a commuter-conversion 90s MTB.
When I installed the Axiom Journey rear rack, I was puzzled that it did not seem to want to go on centered over the wheel. It's not way off, but it was noticeable. I figured maybe one of the mounting arms that go to the seat tube was just a bit warped. The SKS rear fender I installed also did not want to center over the wheel (I know that by itself wouldn't mean anything because there's so much room for play in a fender install).
So I did a lot of searching of related threads here. I triple checked that the wheel was properly set in the dropouts. I flipped the wheel and mounted it to see whether it was dished improperly, but it was still (seemingly) off center to the same side of the bike.
Today I did the string test, running a triangle of string from front of headtube to dropout to dropout and back to headtube, making marks at each spot. There is plenty of room for small error in this method, but I came up with a difference of something like .75 inch (between DS dropout to headtube distance and NDS dropout to headtube distance).
The bike seems to ride fine (although I am pretty inexperienced and probably oblivious to fine distinctions that experienced riders would notice). So my question is: should I even worry about it? Does it sound like a potentially significant problem? Are the guys at my LBS going to think I am insane or annoying to be bringing in a bike with a (potential) problem that is neither readily visible nor noticeable on a test ride? I don't mind being assertive if there's a real problem, but this one seems like it has potential to be over-anxious noob syndrome.
Any advice is greatly appreciated. Does this seem like a problem? If so, what's the best way to approach the matter?
And I promise to be a positive contributor in the future, not just a user.