Making a top tube shorter?
 

Hello all,
Went to two local LBS's to get fit. Both came up with the same numbers: I need a 56 seat tube and a 52 top tube (assuming a 10 cm stem). I've been riding a 56 x 56 lugged steel frame with a 10 cm stem and feel a little too stretched out. Anyways, is it advisable to take my frame to an expert and get the top and down tubes altered to come up with a 52 top tube? Would it be about the same cost to just get a custom frame built? Thanks.
Chris

No. Yes.

Furthermore, unless you are built really weird, those numbers seem off.

If you just chop 4cm of length off the front of the top tube (and downtube), you then also need a longer headtube and longer fork steer tube. If you take the length off the back end of the top-tube (and dont change the angles of the downtube), you also need a shorter seat-tube and new/repositioned seatstays due to the lowered height of the seatube lug. Either way, this will have the effect of raising the entire front end of the bike upward, changing (relaxing) the frame angles and raising the bottom bracket height.
To keep the frame angles constant, you would need to have a shorter headtube and a shorter seat-tube. THis would require removal,replacement or modification of the toptube, downtube, seatstays, headtube and fork steer tube. This is major surgery and would not be cost effective. Try riding your existing bike with a much shorter stem first to see if you even like the suggested reach. If so, find a smaller replacement frame with shorter top-tube to get you the stem+top tube reach that you want. Only potential downside of a shorter seattube measurement is that your range of adjustment for the front stem/handlebar height also drops lower.