Well, that was un expected...

[Lewis Moon]

I recently traded in my (too small) Ritchey Road Logic frame for a 2011 Cannondale Supersix. I wanted a "full on" race bike and was looking forward to frame that was VERY stiff. With the sewer pipe sized down tube and a bottom bracket that looks like a huge tumor, the Supersix promised to be a great sprint bike. It is. What I DIDN'T expect was a plush ride. If anything, the 'six is even more comfy in the bumpies than my steel Serotta Atlanta...by a lot. It's that noticeable.
...and no, I don't have different tires. In fact, the bike has exactly the same gear on it as the Atlanta...because I just stripped and built.
Better living through chemistry.

[batman1425]

It's not a toooo-mahhh, sew him up and get him out of hear.

[notsew]

Would you say that it is laterally stiff and vertically compliant?:banana:

[bobswire]

Alu or CF?

[Lewis Moon]

Alu or CF?

The Supersix is carbon. It's amazing what they can do with differential lay ups.

[Mark McM]

Well, it should only have been unexpected if you believed the industry propaganda. No standard diamond frame has any significant vertical compliance, regardless of material. The majority of frame "plushness" exists only in the minds of bicycle magazine writers. The vertical compliance in a bike actually comes from other components, most especially the tires, but also the saddle & seat post, stem & handlebars, and even the fork.

A good read is Josh Poertner's blog postings about actual testing of vertical stiffness/harshness of frames and wheels when he was working for Zipp, which includes comparing expectations, perceptions, and blind testing.

https://silca.cc/blogs/journal

[verbeke06]

the hi-mod carbon really does make a difference :)