Quote:
Originally Posted by David Kirk
The issue is one of material hardness. Back when Colnago made those tube shapes the material was only slightly harder than warm butter. So they could draw a round tube, put it in a die and squeeze it and get the shape they wanted.
If someone wanted to hydro form a modern high strength steel such as 853 or 953 they would have a very tough time of it. This means that to draw steel into a shape similar to what we see on carbon aero bikes that they would need to use a lower strength material and then use a thicker wall to compensate.
I don't see any of this as impossible and at the same time I see very little market for such a bike.
dave
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I saw a cut cross section of a Specialized Smartweld aluminum hydroformed frame at the headset junction with the top and downtubes. I was not impressed. The wall thickness at the welds was thin and the weld was not full penetration. The hydroforming basically eliminated the tube butting. Those hydroformed tubes look cool, but I don't think the frame is as strong. It must be really hard to control the wall thickness when you balloon a tube out like that.