On my last mtb ride, which was fairly mellow, I noticed a lot of noise in my little ring. I brought it home and had DH look at it -- the problem was actually pretty obvious once the bike was hanging in the stand.

The front derailleur is mounted such that when I go past about the fourth rear cog while in the smallest front ring, the chain is too low and rubs against the bottom of the derailleur. But the front d. only has about 3mm clearance for the big ring up front, so mounting it lower really isn't an option.

This is a high end bike, XS frame size.

So -- I guess a few questions --

If you had a bike where you effectively couldn't use anything past the fourth cog in the front ring, would you be upset? I know that you're supposed to avoid crossing the chain, but to me it seems there's a big difference between "avoid doing this" and this, which effectively prevents me from using half the cogs. (Okay, I guess I could do it and just suck up the noise, but I suspect having the chain rub against the derailleur like that isn't a recipe for long-lasting bike parts.)

Shouldn't the bike shop have noticed this when building the bike and at least mentioned it to me?

Is there any possibility of a different mix of components working better? (I can get an exact list, but I don't remember it all off the top of my head.) Aside from getting a smaller large ring or a bigger small ring, neither of which sound like wonderful ideas from here.

Is the fact that it took me something like 7 or 8 rides to even notice this an indicator that it's not a big deal?

I do tend to hang out in the little ring -- is this just the universe's way of telling me to learn to shift up front more often?