Touring - Comfort = geometry or materials?

A tale of two bikes:

I've a Kona Dew (al frame) modified for moustache bars. Relatively relaxed compact geometry - relatively long chain stays - large, nice tires.

I've also an Easton (al frame) former race bike - upright, traditional geometry - minimum chain stay length - 22mm high-pressure tires.

The latter seems to beat me up on rides less than the former! WHY? From all I've read, the former should be the FAR more comfortable ride! Does the double-butted racing frame absorb more shock than the (probably straight-ga.) Kona? Does the curved carbon fork on the latter absorb more road hash than the absolutely straight fork on the Kona? Are there other factors to be considered?

Inquiring minds want to know...

My guess is that in an effort to lighten the frame as much as possible, the double butted (thinned out) racing frame ends up having more give, or flex, than the Kona. Although the larger tire would seem to give the Kona an edge in ride, ultimate wheel stiffness will also have an impact. Perhaps the Kona wheel is, in fact, stiffer than the Easton wheel.

I doubt the fork has a lot to do with it assuming neither bike shimmies on a fast descent (45-50mph). If you get shimmy from the Easton bike then that would likely indicate the fork on the Easton isn't stiff enough. The priority in making forks is to make them stiff. All manufacturers shoot for stiffness in the fork blades and overall construction. A stiff fork doesn't lend itself to front end shimmy. In frame construction however, each manufacturer targets frame areas with various stiffnesses to provide a certain, or target, ride characteristic.

I suspect that your case is somewhat of an exception. Today most modern racy style aluminum bikes are stiff to brutally stiff. Carbon is moderately stiff to extremely stiff. Steel is moderately forgiving to moderately stiff.

Aluminum has the reputation of being very stiff in general but, it doesn't have to be. Pegorettis, even though they fall under the racing category, have the reputation of being excellent long distance riding bikes. My guess is partly the material, partly the geometry, partly the wheels, and partly the instict or talent of the frame designer. The ultimate ride is mostly dictated by the sum of all the parts.

Makes sense to me. Thanks! The wheels, by the way, also radically different - the Kona has the stock 32-spoke, 3x with deep-V rims. The Easton has Campagnolo Vento with way fewer spokes, different lacing, and deep-V rims.

Mostly, comfort = tires a lot more than frame material.