Originally Posted by
dunderhi
Don't forget about Columbus SP. I think that was their stiffest offering. I replaced my 531SL frame with a SP frame and there was a world of difference. Then again, I replaced the SP frame with an early Cannondale which was absurdly stiff.
SP was made from the same alloy as SLX, but instead of the .9/.6/.9 wall thickness of SLX, SP had 1.0/.7/1.0 wall thicknesses. SPX also came in longer lengths, as it was designed for larger frames. SP also came out shortly after SLX was introduced.
For anyone curious as to how wall thickness and diameter effect tube stiffness. Wall thickness will increase tube stiffness in a linear fashion. Increase wall thickness 20%, then stiffness increases 20%. Stiffness increases by the cube of diameter. So increasing wall thickness might slightly increase the tube stiffness, doubling the diameter will increase it's stiffness 8X. This is for bending along the tubes linear axis. Torsional resistance of a tube increases by the 4th power of a diameter, so this doubling of diameter on a tube will make it 16X more resistant to twisting forces. It is a the torsional loads that allow the linear flex of a tube on a bicycle.