I am far from geeky about the design of bikes, and not normally particularly observant about them. But when I saw this, I had to wonder about how it met the rule about bikes having to maintain the 'traditional double triangle shape'.
Did I imagine such a rule? I know that the head tube often means that the front 'triangle' is more of a quadrilateral, but this is something quite different. It looks to me that the top tube and the seat stay are one continuous piece, and that the seat tube (which is not directly related to the seat here) does not meet that part of it that has the line of a top tube. The regs say
“The elements of the frame shall be laid out such that the joining points shall follow the
following pattern: the top tube connects the top of the head tube to the top of the seat tube ;" ( p 23/4 of this doc)
But it really doesn't seem to do so: the top tube continues beyond the seat stay to the bottom of the seat post , while the seat tube is connected to the seat stay, not the top tube.
The same paragraph states "The seat post ... may be attached to the frame anywhere on the seat tube and/or top tube": it certainly isn't attached to the seat post, so the horizontal extension to it must be top tube. In which case, unless the principle of a forked top tube is being invoked, the seat tube does not connect to the top tube.
I also see (ibid. p 29) "The top tube may be inclined (sloping) provided that this frame element is contained within
a horizontal box of 160 mm height." But the juncture illustrated as the relevant point for that 160 mm measurement really doesn't exist. Does the connection between the seat tube and the seat stay look to be within that distance of the top edge at the front of the top tube (I have very poor perception of that sort of measurement)
I guess it had to be UCI licenced, but it looks questionable to me. Anyone able to cast light?
Is this a configuration that is not uncommon, and has simply passed me by before? (very possible, see my opening sentence)
View: https://www.instagram.com/p/CvCEsS_MsPx/?img_index=1
Regardless, it's a pretty thing.
Did I imagine such a rule? I know that the head tube often means that the front 'triangle' is more of a quadrilateral, but this is something quite different. It looks to me that the top tube and the seat stay are one continuous piece, and that the seat tube (which is not directly related to the seat here) does not meet that part of it that has the line of a top tube. The regs say
“The elements of the frame shall be laid out such that the joining points shall follow the
following pattern: the top tube connects the top of the head tube to the top of the seat tube ;" ( p 23/4 of this doc)
But it really doesn't seem to do so: the top tube continues beyond the seat stay to the bottom of the seat post , while the seat tube is connected to the seat stay, not the top tube.
The same paragraph states "The seat post ... may be attached to the frame anywhere on the seat tube and/or top tube": it certainly isn't attached to the seat post, so the horizontal extension to it must be top tube. In which case, unless the principle of a forked top tube is being invoked, the seat tube does not connect to the top tube.
I also see (ibid. p 29) "The top tube may be inclined (sloping) provided that this frame element is contained within
a horizontal box of 160 mm height." But the juncture illustrated as the relevant point for that 160 mm measurement really doesn't exist. Does the connection between the seat tube and the seat stay look to be within that distance of the top edge at the front of the top tube (I have very poor perception of that sort of measurement)
I guess it had to be UCI licenced, but it looks questionable to me. Anyone able to cast light?
Is this a configuration that is not uncommon, and has simply passed me by before? (very possible, see my opening sentence)
View: https://www.instagram.com/p/CvCEsS_MsPx/?img_index=1
Regardless, it's a pretty thing.
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