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These geometries seem off to me(9 posts)

These geometries seem off to meHBPat
Jun 20, 2002 10:34 AM
This is for a Bianchi. I know that the virtual TT seems to match up fairly well, but I don't get their sizing. If I fit on a 57 from everybody else would I ride a 59? Even the virtual TT for the 57 seems short, and the C-C seat tube seems way too short and I think that I'd have to jack the seat way up making it feel like a TT bike. Is the Alloro a TT bike?
the term "size" is just a referenceclimbo
Jun 20, 2002 10:45 AM
just like S, M and L. This is a standard road bike.

The non-sloping TT bikes are measured by the ST to the top of the collar thus giving a larger "size" than the actual ST if measured center to center. It looks as though they "size" the sloping bikes this way too so that your bike size would be the same for a sloped TT model or a horizontal TT model.
from everyone else?laffeaux
Jun 20, 2002 12:14 PM
The statement, " If I fit on a 57 from everybody else would I ride a 59?," is a bit misleading as there is no "everyone else" sizing. The only thing you can count on is no consistency in measuring size. Find a dealer that sells Trek and Klien (both Trek products) and see what size you fit in each of those makers. I think you'll find that sizes vary widely, not just from Bianchi.
It's consistentMcAndrus
Jun 20, 2002 12:50 PM
My Veloce is nominally a 61cm frame and it has a 58.5cm top tube. That seems consistent with the measurements you have for the Alloro.

Bianchis are dimensioned like other Euro brands with relatively short top tubes. I've ridden bikes as "small" as 58cm and they fit me fine because their top tubes are longer.

As someone else said, the only standard in bike sizing is that there is no standard.
Bianchi calls it a racing bikeMcAndrus
Jun 20, 2002 12:53 PM
I guess my question needs rephrasingHBPat
Jun 20, 2002 1:44 PM
As I re-read that I am a little confused myself.

What I am getting at is the difference between a compact (or sloping) geometry and a standard one. I have never ridden a compact frame and am just wondering how they compare to a stardard frame. Do you fit yourself on them differently, or do the same rules apply as when you're fitting yourself on a standard frame.

I know I will just have to ride one but I was hoping I could get some advice first. Sorry if I was confusing, or slightly uninformed with my first question.
use the top tube lengthlaffeaux
Jun 20, 2002 2:31 PM
If you mean is standover height the same? The answer is no. Determine the TT length that you need and base fit on the "effective top tube length" measure.

I ride a compact frame, and I have no idea what size it is (it's an XL), but I do know it has an effective TT of 59cm, and that works for me. I have plenty of standover clearance - i.e. probably 3 inches or more.
Fitting is 95% the same...TJeanloz
Jun 21, 2002 4:48 AM
Bianchi is at least kind enough to give pretend seat tube and top tube lengths, so if you were on a 57cm standard bike, you'd be on a '57' compact, even though the 57 on the compact refers to a 'virtual' measurement.
simple analysis....C-40
Jun 21, 2002 1:37 PM
The frame "size" is actually the ENTIRE seat tube length, which is extended 3cm above the top tube.

Since Bianchi does not list a "virtual" (horizontal) seat tube length, you can only go by the standover height, presumably measured in the middle of the top tube and the top tube length to gage the size. I would also insist on knowing the head tube length to determine handlebar height.

If you have 3-5cm of standover clearance and an appropriate TT length, that's you size.