Tom Sherman wrote:
SMS aka Steven M. Scharf wrote:
[...]
Carbon frames that large tend to have problems of too much flex, which
is what the reviews of the 64cm Madone found. Colnago seems to have
solved this problem in their carbon fiber frames and they go up to 65 cm.

The larger CFRP frames being too flexible is just poor engineering, and
has nothing to do with the inherent properties of CFRP.

To reduce the flex in the larger frames requires some engineering
enhancements because of the the inherent properties of carbon fiber.
Apparently Trek just made the frame larger, without understanding that
this wouldn't work.

Colnago describes what they did at
"http://www.colnago.com/en/catalogo2008/extremepower.php".