# Sizing C50 to M10



## ddesmonts (Nov 17, 2004)

I have a 2005 C50 Traditional 57. What size would that best match on a current model Colnago M10 (2012)? I do not have the original geometry for the C50 (nor the frame in my possession), but did find a chart for 2007:
ST-570, TT-557, HT-157. I do run a 120 stem with a couple centimeters of spaces below.
In a M10, a 54s was recommended, but I am questioning it as slightly large and feel the 52s may be a better fit. Better to err on small if it was necessary, no?

Per Colango site, M10 specs:
52s: ST-520, horizTT-550, HT-166
54s: ST-540, horizTT-565, HT-181

Excelsports has a note:
"A word on sizing. Colnago describes the frame size as the actual seat tube length from the center of the bottom bracket to about the middle of the seat collar extension. Since most manufacturers list virtual sizes on sloping top tube frames (the size to frame would feel like if the bike had a horizontal top tube) Colnagos run larger than what they may seem at first glance so we strongly suggest sizing off the virtual top tube length and head tube length. Another way to size the "s" (s for sloping top tube) framesets is to add 4cm for a virtual size. So, for example a 52s would ride like a 56cm." 

and a 54 would ride like a 58 - my 57 is in between.....
Thanks for any insight.


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## icsloppl (Aug 25, 2009)

My C-50 is 58 traditional. The 54 sloping is a very good match. 
Whether you fit 54 or 52 will likely be a matter of how much seatpost you have showing on your 57. Mine has 20cm from the top of the collar to the top of the seat.


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