Lower psi in front tire: is this normal?

[SouthernBelle]

Do you have a different brand of tube in each tire?

I've noticed differing rates of air loss between brands.

[Ana]

Nope, both tubes are the same brand.

I went into my LBS today to get a replacement Trek grocery bag, as one of the rivet-things came off of it and Trek's warranty covers it for a year but I had to go into an "authorized local dealer" to file the claim

I mentioned the problem and two things came up:

1) maybe I rode over something hazardous (very possible) and should submerge it in the tub or sink to look for bubbles

2) sometimes the little thing inside the shraeder valve (the base of the pointy thing) gets unscrewed a bit....causing a very slow leak.

Soooo I got a new tube and will check my tire....um....tomorrow, maybe

Oh, and I found these great inner tubes made in the U.S. with "slime" in them and they're the same price as the tubes I just got (well, I'm excited).