Quote Originally Posted by Catrin View Post
So I would just raise the seatpost to the mark that says "this high and no higher" and measure from the bottom bracket to the top of the seat tube. That seems simple enough. I will also use Oakleaf's suggested method and see how they compare

Thanks for the tips - from the base measurement I took this morning it may actually turn out to be a 17 inch bike - which would explain why it is too big for me and I know someone who might be interested in it IF it is a 17 inch I need to make very certain though - I now wish I hadn't removed that sticker.
Maybe I'm just totally confused, but I think you just measure the length of the seat tube from the center of the bottom bracket. Leave the seat post out of the equation. In looking at Trek's geometry page, this is indeed how they measure the bike. The seat tube--if it is indeed a 15--should measure 15 inches from the center of the bottom bracket.

http://www.trekbikes.com/us/en/bikes...th/fx/76fxwsd/