Now you need to know if the other one slopes as well.. and how much..
43 or 49 or 52 are all viable if there is a radical difference in top tube slope.
So, I often, use a top tube length, as well .. since with a sloping top tube
shorter seat tube You raise the seatpost as required.
measure a Virtual, a horizontal line between centers.. so neutral,
whether a sloping or level top tube.
A decent spec chart should give a virtual length if theTT is not level.
Last edited by fietsbob; 02-10-12 at 01:37 AM.