Fierte Top Tube

[ThasFACE]

Hopefully this isn't dumb...

I've put a lot of miles on my Fierte Ti (58) in the year that I have owned it, but just today I noticed something about the top tube and I don't know if something has happened to the frame or if it is still unsullied.

Anyway, I noticed some gunk near the seat clamp and, while cleaning it (sap) off, noticed that the top tube of the bike tapers to an oval-ish shape just before it meets the seat tube. I don't know how I never noticed it before, but the non-circleness of the tube (where it meets the seat tube) concerned me. It doesn't feel like the 'sharp' bend of the oval is at quite the same point on both sides of the tube (although it might be), so I'm wondering if my bike hasn't been the victim of some sort of crush. I should note that a mysterious (long, straight) scrape has appeared on my k-wing, which has done nothing to allay my fears that something bad has happened to my bike without my knowledge.

Is the tube as it should be? (you know, based on my poor description)

[Serpico]

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[Needs Help]

Is the tube as it should be?
It's called an ovalized top tube. Along the long diameter, the tube is stiffer than along the short diameter. So, if you were a bicycle manufacturer, you might orient the tube with the long diameter running horizontal to the ground to provide more side to side(lateral) stiffness, and the short diameter running vertically to provide more vertical compliance. Which way is your tube oriented?

Also, think about this: if you had a circular top tube welded to your seat tube, and you crushed the top tube into an oval shape, would the circular welds break free from the seat tube, and then reattach themselves in an oval shape?

[Brian Smith]

The top tube of your Fierte Ti was itentionally ovalized in the construction process. It is a common Serotta practice when the diameters of middle sections of the two tubes are the same. It is chiefly, atmo, a fabrication concern, and produces what could be called a more aesthetically pleasing joint. Don't worry - it was MEANT to be that way!

[ThasFACE]

Which way is your tube oriented?



The long diameter is oriented parallel to the seat tube (up and down; perpendicular to the ground).

Also, think about this: if you had a circular top tube welded to your seat tube, and you crushed the top tube into an oval shape, would the circular welds break free from the seat tube, and then reattach themselves in an oval shape?


I guess that I was thinking that it might have gotten squeezed laterally and that it did not necessarily break the welds. The more I think about this, though, the dumber it sounds (given that the joint looks 'factory' and Brian Smith has offered some nice info).