Nope, I have a 80mm also. It has to do with the geometry and suspension design so that when the suspension sags under your weight the steering is at the right angle.

Cari, have you looked at a Marin Mt Vision? I'm a smidge shorter than you and have one with a 100 mm fork on it. It has a longer wheelbase than the Racer X. I haven't a clue what my inseam is. I set all my saddles at 70cm from the ctr of the crank to the top of the saddle.

What type of trails are you riding?