Long top tubes - who makes'em?
04-14-05, 12:04 PM
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Long top tubes - who makes'em?
Using Leonard Zinn's bike fit calculations, I estimate that I need a frame of the following dimensions:
Frame size - 54cm
Top tube length - 61.5cm
Stem length - 118mm (rounds up to 120mm)
I used the most conservative ("casual rider") factors to achieve these numbers. The "aggressive rider" factors would have resulted in a significantly longer top tube length.
Obviously, I have short legs, but long torso and arms.. Looking through multiple manufacturer's catalogs, I've yet to see any frames that come even close to these specs.
If I go with a compact frame of sloping top tube style (Specialized Roubaix), I can go as large as a 58cm frame size before the standover height becomes an issue, but even then, the top tube length is less than optimal.
Now the questions:
What styles of bikes (racing, tri, comfort, touring, etc.) are likely to have the longest top tubes relative to frame size?
How much compensation can be made with extra stem length for a short top tube?
Can anyone recommend any specific makes/models that would be a close fit for my measurements?
Thanks!
Frame size - 54cm
Top tube length - 61.5cm
Stem length - 118mm (rounds up to 120mm)
I used the most conservative ("casual rider") factors to achieve these numbers. The "aggressive rider" factors would have resulted in a significantly longer top tube length.
Obviously, I have short legs, but long torso and arms.. Looking through multiple manufacturer's catalogs, I've yet to see any frames that come even close to these specs.
If I go with a compact frame of sloping top tube style (Specialized Roubaix), I can go as large as a 58cm frame size before the standover height becomes an issue, but even then, the top tube length is less than optimal.
Now the questions:
What styles of bikes (racing, tri, comfort, touring, etc.) are likely to have the longest top tubes relative to frame size?
How much compensation can be made with extra stem length for a short top tube?
Can anyone recommend any specific makes/models that would be a close fit for my measurements?
Thanks!
04-14-05, 12:14 PM
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Thats nuts unless your arms/torso are stupendously long in relation to your inseam. Like, you were once 6'8" tall but lost part of both legs to an accident or something (heaven forbid!). I think you did the input wrong.
I am 6'4" tall, long arms/torso and would not take that long a top tube.
I am 6'4" tall, long arms/torso and would not take that long a top tube.
04-14-05, 12:18 PM
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Originally Posted by FarHorizon
Using Leonard Zinn's bike fit calculations, I estimate that I need a frame of the following dimensions:
Frame size - 54cm
Top tube length - 61.5cm
Stem length - 118mm (rounds up to 120mm)
I used the most conservative ("casual rider") factors to achieve these numbers. The "aggressive rider" factors would have resulted in a significantly longer top tube length.
Obviously, I have short legs, but long torso and arms.. Looking through multiple manufacturer's catalogs, I've yet to see any frames that come even close to these specs.
If I go with a compact frame of sloping top tube style (Specialized Roubaix), I can go as large as a 58cm frame size before the standover height becomes an issue, but even then, the top tube length is less than optimal.
Now the questions:
What styles of bikes (racing, tri, comfort, touring, etc.) are likely to have the longest top tubes relative to frame size?
How much compensation can be made with extra stem length for a short top tube?
Can anyone recommend any specific makes/models that would be a close fit for my measurements?
Thanks!
Frame size - 54cm
Top tube length - 61.5cm
Stem length - 118mm (rounds up to 120mm)
I used the most conservative ("casual rider") factors to achieve these numbers. The "aggressive rider" factors would have resulted in a significantly longer top tube length.
Obviously, I have short legs, but long torso and arms.. Looking through multiple manufacturer's catalogs, I've yet to see any frames that come even close to these specs.
If I go with a compact frame of sloping top tube style (Specialized Roubaix), I can go as large as a 58cm frame size before the standover height becomes an issue, but even then, the top tube length is less than optimal.
Now the questions:
What styles of bikes (racing, tri, comfort, touring, etc.) are likely to have the longest top tubes relative to frame size?
How much compensation can be made with extra stem length for a short top tube?
Can anyone recommend any specific makes/models that would be a close fit for my measurements?
Thanks!
04-14-05, 12:21 PM
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Have a look at Lemond (and the other bikes in the Trek group: Trek, Klein); not freakishly long tt but a more stretched out than a typical Italian. Still, if what you say is really the case, you may need to go custom.
04-14-05, 12:25 PM
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Originally Posted by FarHorizon
Using Leonard Zinn's bike fit calculations, I estimate that I need a frame of the following dimensions:
Frame size - 54cm
Top tube length - 61.5cm
Stem length - 118mm (rounds up to 120mm)
I used the most conservative ("casual rider") factors to achieve these numbers. The "aggressive rider" factors would have resulted in a significantly longer top tube length.
Obviously, I have short legs, but long torso and arms.. Looking through multiple manufacturer's catalogs, I've yet to see any frames that come even close to these specs.
If I go with a compact frame of sloping top tube style (Specialized Roubaix), I can go as large as a 58cm frame size before the standover height becomes an issue, but even then, the top tube length is less than optimal.
Now the questions:
What styles of bikes (racing, tri, comfort, touring, etc.) are likely to have the longest top tubes relative to frame size?
How much compensation can be made with extra stem length for a short top tube?
Can anyone recommend any specific makes/models that would be a close fit for my measurements?
Thanks!
Frame size - 54cm
Top tube length - 61.5cm
Stem length - 118mm (rounds up to 120mm)
I used the most conservative ("casual rider") factors to achieve these numbers. The "aggressive rider" factors would have resulted in a significantly longer top tube length.
Obviously, I have short legs, but long torso and arms.. Looking through multiple manufacturer's catalogs, I've yet to see any frames that come even close to these specs.
If I go with a compact frame of sloping top tube style (Specialized Roubaix), I can go as large as a 58cm frame size before the standover height becomes an issue, but even then, the top tube length is less than optimal.
Now the questions:
What styles of bikes (racing, tri, comfort, touring, etc.) are likely to have the longest top tubes relative to frame size?
How much compensation can be made with extra stem length for a short top tube?
Can anyone recommend any specific makes/models that would be a close fit for my measurements?
Thanks!
Something's not right with your calculations. I think that the longest top tube your gonna find on a "standard" 54 cm frame (c-c or c-t) depending on the the seat and head tube angles is about 56.5. Even with a 14 cm stem, you're still not close to the total length that you've calculated.
04-14-05, 12:26 PM
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Because of the geometry of my bike's frame, it allows you to ride a pretty small frame while providing a relatively long top-tube. However, I think a 61.5cm effective top-tube on 54cm frame is highly disproportionate. Are you certain of those measurements? Perhaps you're built like this??? 
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04-14-05, 12:27 PM
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According to the competitive cyclist fit calculator, I ended up being a 54-55 seat tube and 57cm top tube. I got a 56cm Fuji Team SL frame that I haven't built up yet, but its measurements aren't too far away from those numbers. I also figured that my measurements were less than perfect and the fit calculator isn't completely perfect either, so the 56 should do fine aside from the standover height being a little on the tall side.
04-14-05, 05:20 PM
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Originally Posted by biker7
agree with the above comments. Post your height...biking inseam, and arm shirt sleeve length etc for better feedback.
Floor to crotch - 33" = 83.82cm
Arm length - shoulder blade peak to wrist bone - 24.5" = 62.23cm
Floor to sternal notch - 60" = 152.4cm
Frame size = Floor to crotch measurement minus 30cm = 54cm
Top tube length = (Floor to sternal notch minus floor to crotch plus arm length) times 0.47 = (152.4-83.82+62.23)*0.47 = 61.5cm
Stem length = (floor to sternal notch minus floor to crotch plus arm length) times 0.09 = (152.4-83.82+62.23)*0.09 = 11.77cm or 120mm
If I've done something wrong, please enlighten me (it's sure possible...) Thanks again!
04-14-05, 05:50 PM
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That calculator is screwed. Apparently I need a 72cm top tube.
04-14-05, 06:03 PM
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totally jacked, claims I need a 64 cm top tube -- i ride a 55 cm top tube.
try the competitive cyclist fit calculator. works pretty well for me.
try the competitive cyclist fit calculator. works pretty well for me.
04-14-05, 06:20 PM
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Originally Posted by howling.fantods
totally jacked, claims I need a 64 cm top tube -- i ride a 55 cm top tube.
try the competitive cyclist fit calculator. works pretty well for me.
try the competitive cyclist fit calculator. works pretty well for me.
-Z
04-14-05, 06:28 PM
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https://www.competitivecyclist.com/za...LCULATOR_INTRO
wrench science's is good too.
https://www.wrenchscience.com/WS1/Sec...ing/Height.asp
wrench science's is good too.
https://www.wrenchscience.com/WS1/Sec...ing/Height.asp
04-14-05, 07:23 PM
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Well **that's** interesting - using the "competative fit" measurements, recommendations are for a frame size between 56 and 58 cm, a top tube between 58 and 60 cm, a 110-120mm stem, and a setback seatpost. With the seatpost setback, which Zinn didn't mention, I think the competative-fit measurements are not far from Leonard Zinn's (except for seat tube size).
