Looking into purchasing a new '09 BMC Pro Machine for my wife. Right now she's on a Trek 5500 size small frame (52cm) that runs a top tube length of 53. She's got a Ritchey stem on the bike that I believe is 120 mm. Here's a link to a website with the geometry of her bike

http://web.archive.org/web/200210150.../5500_geo.html

I'm looking into building up an '09 BMC Pro Machine for her. She VERY briefly rode both a size 49 and 51 in the Pro Machine at a shop here in town that no longer carries those bikes. She by no means had a formal fit on the bike, but said she thought she preferred the 51. Unfortunately there's no shops in town any more that carry these bikes. As many of you know, BMC has odd sizes when you look at the actual frame "size" compared with the top tube length. Here's a link which shows the geometry of the BMC bikes:

http://www.competitivecyclist.com/ro...c-01-5429.html

The guy at our local shop here in town as well as the dealer I'm going to purchase the bike from recommended putting her on the 51 BMC (which has a 54 top tube) and shortening up her stem a bit, which would make the fit similar to her Trek. Before I pull the trigger was just hoping to get some thoughts from others on here who may have had similar fitting experiences. Any thoughts/advice would be much appreciated! If it helps, here's a few measurements from the CC fit calculator. These measurements would seem to say go with the 49 BMC......so who knows.

Measurements
-------------------------------------------
Inseam: 31.5
Trunk: 22.5
Forearm: 13
Arm: 25
Thigh: 22.5
Lower Leg: 20.5
Sternal Notch: 54.5
Total Body Height: 65.5