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55cm toptube, 48cm seattube, 15.5cm headtube; weird?(8 posts)

55cm toptube, 48cm seattube, 15.5cm headtube; weird?cipollini
Aug 9, 2002 10:56 AM
believe i need a frame with this geometry:
55cm TT
48cm ST Center/Top
15.5cm HT
is this too sloping?
wonder what you think
I think that's not enough data...TJeanloz
Aug 9, 2002 11:08 AM
I don't think anybody can comment on whether that's the bike that will fit you or not from this data. It would be a very, very strange size, but weirder things have happened.
more datacipollini
Aug 9, 2002 11:17 AM
ok here's more:
73° seatangle, 73° headangle, chainstay: no idea

I tried a tcr today: 55.5cm toptube, 50cm seattube CT, 14.5cm headtube

I like to have the bike a bit shorter and have my handlebar a bit higher, so i thought 55TT, 48CT, 15.5HT would be ok

my lenght: 1.77m
inseam: 85cm
but I have a long upperbody and long arms
more datajjohnson05
Aug 9, 2002 7:33 PM
This actually sounds pretty good if you are looking at about a 7 degree slope to the top tube. What is really critical with sloping top tubes is to know the virtual TT length and the head tube length. It doesn't really matter where the seat tube stops if you make up the difference with seat post. But the length across the top is VERY critical, it determines where your body is centered on the bike. The 155 mm headtube is average+ for your size. The other very critical dimension you negelcted to mention is the setback. It determines your body position in relaton to the cranks, which are a very important part of the rider/bike interface. In your case, if you are a classic roadie, you probably want a setback of about 16cm. Having said all this, are you having a custom built frame made for you? If not try to find an "off-the-peg", or mass produced frame that suits your requirements. Sloping top tubes may seem to offer a bit more flexibility, but not if the measurements across the top (top tube and setback) are not right. Good luck!
more datacipollini
Aug 10, 2002 7:33 AM
hello, thanks for your reply!
I haven't thought about the setback yet! i agree that's critical

scott from JAVELIN ( wants to build a custom frame for me
but how do i know the setback is going to be ok?
I will send him some more emails before ordering to make sure

I need a effective toptube of 55cm
and because i want my bar a bit higher I thought of a longer headtube
but all other compact frames (seven, merlin, specialized) have shorter headtubes (!)

thanks again!
more datajjohnson05
Aug 10, 2002 9:35 AM
Check out this link to Orbea,, to view their sloping top tube geometry. They do really nice sloping top tube bikes in the full range of Columbus tubing. You could ride their 55 or 56, not vary the tt length form one size to the other, but have a 165mm or 175mm headtube to choose from. We have a standard geometry Orbea Starship and it is great and at a great price. Builds to about a 16 pound bike. These guys will also custom built and/or custom paint.
more datajjohnson05
Aug 10, 2002 9:40 AM
Sorry, I didn't read your post carefully enough. It looks like the Orbea Voop 54 is exactly what you are looking for. 47/55/155, ST/TT/HT. Go for it!
Aug 10, 2002 10:11 AM
indeed, this is exactly what i want
thank you very much!
this is my new frame!