If you are 5'5" with a 30.5 inseam (and I'm assuming you mean a 30.5 cycling inseam...not your pants, right?)...then a 17" might be too small.

I'm 5'4" with a 28.5" cycling inseam, and I ride a 19" classic. Mine is a 2004, so I don't know if they changed the geometry between 1998 and 2004, but a 17" would be too small for me.

You could try sending a PM to Triskeliongirl. She's got specs for some older Terry's saved on her computer. I don't know if her's go back to 1998, but it's worth a shot. I can also post the specs for the 2004 Classic when I get home tonight if you think that might help you. I believe I have them saved on my home computer.