Serotta Tube Designations

[pjmsj21]

Can someone explain the designations that are used for various carbon tubes that Serotta uses. For instance what is the difference between an 8.5 versus a 6.5 top tube? I assume one is lighter than another but does that translate into stiffness?

As always thanks.

[RkyMtn]

As I have come to understand it, The tube number designation relates to the tube's stiffness. The higher the number, the stiffer the tube.

What I would like to know is what is changed between these stiffness designations. i assume is it butting and tube wall thickness. Anything else?

Cheers,

Eric

[Serotta_Carbon]

Good question.

The tubing sets are ranked in order of stiffness in bending and torsion. The 8.5 tube set is stiffer than the 6.5 etc. These properties are achieved by manipulating the fiber angles and modulus of each ply of the lay-ups rather than just using less or more material. This way all tubes are physically the same size & weight but give unique mechanical properties.

A stiffer frame doesn't have to mean additional weight...

Thanks!