sorry- definitely the rear. It's like when you're pedaling, your foot suddenly jumps forward, sometimes three or four times in succession. Even on level ground, just pedaling easily, it'll slip- feels like it's jumping the teeth. It doesn't change gears on it's own. I haven't removed the rear wheel, but can check the quick release. I guess the cable can stretch with new bikes, so I'll bring it to work tomorrow to drop it off at the bike shop. Hopefully it'll do it for them so they know what I'm talking about.
vickie