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How real is a tall head tube to ride?
With Paris-Roubaix, everyone's talking about the value of "relaxed"
frame geometry again, specifically the long head tube and the benefits they bring. My question is, what ride differences are there b/n a frame with a longer head tube and a regular road frame that has more spacers inserted below the stem, thereby achieving a longer virtual head tube? I've asked this question a number of times elsewhere and no one seemed to be able to answer it directly. -- |
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#2
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How real is a tall head tube to ride?
"Artoi" wrote in message ... With Paris-Roubaix, everyone's talking about the value of "relaxed" frame geometry again, specifically the long head tube and the benefits they bring. My question is, what ride differences are there b/n a frame with a longer head tube and a regular road frame that has more spacers inserted below the stem, thereby achieving a longer virtual head tube? I've asked this question a number of times elsewhere and no one seemed to be able to answer it directly. -- I've never ridden cobbles very far but for normal road riding a longer head tube will result in a frame that is torsionally softer. Think of a twisted frame with the top tube and down tube out of plane. A shorter head tube is torsionally stiffer than a long head tube and will resist this kind of flex. The closer the top tube is to the down tube where they connect to the head tube, the stiffer the frame (all other things being equal). Adding spacers will achieve a taller geometry without affecting frame flex and handling. The worst affect of torsional flexing is in the handling of the bike where the wheels go out of alignment (head tube out of plane with seat tube) and the bike does not track well. Phil H |
#3
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How real is a tall head tube to ride?
that's relaxed carbon tube geometry? tall head tube geometry? tall? what does tall have to do with geometry? the angle determines geometry. would seem the rear lever from longer seat tube vastly overpowers effects at the realtively shgort, nay fractional comparable lengths up at the head tube. anyway, its carbon right? who knows ??? you ask a good question. spacers? (forgive me being an *&&&**) "Adding spacers will achieve a taller geometry without affecting frame flex and handling. " adding spacers automatically adds flex everywhere. spacers, as geometry ? hmmmm non-euclidean ? reimann space effetc? anyway ignore this post. gibberish |
#4
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How real is a tall head tube to ride?
In article ,
Artoi wrote: With Paris-Roubaix, everyone's talking about the value of "relaxed" frame geometry again, specifically the long head tube and the benefits they bring. My question is, what ride differences are there b/n a frame with a longer head tube and a regular road frame that has more spacers inserted below the stem, thereby achieving a longer virtual head tube? I've asked this question a number of times elsewhere and no one seemed to be able to answer it directly. -- It's hard to answer because it doesn't entirely make sense, especially since I haven't seen any of these discussions about "relaxed" frame geometry, long head tubes, etc. IMHO the benefit is making the bike fit your particular dimensions for your particular purpose. At 6'4" and 215 pounds, I ride bikes ranging from 60 cm to 64 cm center-to-top. One has "laid back" geometry (72/72), one has "neutral" geometry (73/73.5) and one has a mix (74/72.5) (all parenthetical angles are head/seat tube). Do I notice a huge difference switching from bike to bike. No, and what difference I notice is only for about a minute when I start riding. In terms of fit, it's easiest to get the tallest of the bikes adjusted to fit me comfortably. The smaller frames make it hard to get the bars up high enough to be comfortable on long rides (about 2 cm below the saddle). I have stems with long quills as a result and they look a little odd. Back when I raced I had the bars 6-8 cm below the saddle for aerodynamics and the smaller frames made that easier to achieve. Paris-Roubaix is an unrealistic yardstick. Few of us spend our days hurtling as fast as we can across ancient cobblestones covered in manure. Most of us might ride on a gravel road or have to contend with the failing American infrastructure bequeathed to us by nearly three decades of anti-government anti-tax arrant nonsense. Fatter tires would be a better investment than relaxed geometry and long head tubes... |
#5
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How real is a tall head tube to ride?
right better tires does it. try your quick frame shod (eeyaqyayahaha "shod') shod with mitty racing tires. ride on a narrow berm over sand, amacite, sand, grass/ sand gloosy tar whathaveyou? during rush hour and the quick geometry becomes ahhhpparent. continuing sudden changes in grip exaggerate each geometry. Imagine sand sprinkled over ice would do similar you know lika skid pad. |
#6
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How real is a tall head tube to ride?
In article ,
"Phil Holman" piholmanc@yourservice wrote: "Artoi" wrote in message ... With Paris-Roubaix, everyone's talking about the value of "relaxed" frame geometry again, specifically the long head tube and the benefits they bring. My question is, what ride differences are there b/n a frame with a longer head tube and a regular road frame that has more spacers inserted below the stem, thereby achieving a longer virtual head tube? I've asked this question a number of times elsewhere and no one seemed to be able to answer it directly. -- I've never ridden cobbles very far but for normal road riding a longer head tube will result in a frame that is torsionally softer. Think of a twisted frame with the top tube and down tube out of plane. A shorter head tube is torsionally stiffer than a long head tube and will resist this kind of flex. The closer the top tube is to the down tube where they connect to the head tube, the stiffer the frame (all other things being equal). Adding spacers will achieve a taller geometry without affecting frame flex and handling. The worst affect of torsional flexing is in the handling of the bike where the wheels go out of alignment (head tube out of plane with seat tube) and the bike does not track well. This makes sense. So in other words, what people/companies refers to as "relaxed geometry" is actually one that is a torsionally less stiff frame. Then the issue here is, why would it be considered to be more comfortable? By comfortable I would have assumed its more vertically compliant. Frames in this category include Giant's OCR range, Specialized Roubaix range etc. -- |
#7
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How real is a tall head tube to ride?
In article
, datakoll wrote: that's relaxed carbon tube geometry? tall head tube geometry? tall? what does tall have to do with geometry? the angle determines geometry. would seem the rear lever from longer seat tube vastly overpowers effects at the realtively shgort, nay fractional comparable lengths up at the head tube. anyway, its carbon right? who knows ??? you ask a good question. spacers? (forgive me being an *&&&**) "Adding spacers will achieve a taller geometry without affecting frame flex and handling. " adding spacers automatically adds flex everywhere. spacers, as geometry ? hmmmm non-euclidean ? reimann space effetc? anyway ignore this post. gibberish Well, not if you look at what those companies have to say about their bike models like Giant's OCR and Specialized's Roubaix models. Even Cervelo have a R3 SL model. So irrespective whether the concept is gibberish, these statements are real. -- |
#8
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How real is a tall head tube to ride?
forks stuck in short head tubes move around easier, more flexibly,
than forks stuck in longer head tubes, Zoooo given carbon characreistcs (whatever that is) trail increases are handled best thru longer head tubes. Prob also some rather esoteric computer generated human feed insanity on pressure wavelength damping (PWD), sensory threshold cobblestone impact absorption quotients. The usual smoke: Our equipment runs downhill and floats, your crap runs uphill and sinks... |
#9
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How real is a tall head tube to ride?
On Apr 16, 7:27 am, Artoi wrote:
In article , "Phil Holman" piholmanc@yourservice wrote: "Artoi" wrote in message ... With Paris-Roubaix, everyone's talking about the value of "relaxed" frame geometry again, specifically the long head tube and the benefits they bring. My question is, what ride differences are there b/n a frame with a longer head tube and a regular road frame that has more spacers inserted below the stem, thereby achieving a longer virtual head tube? I've asked this question a number of times elsewhere and no one seemed to be able to answer it directly. -- I've never ridden cobbles very far but for normal road riding a longer head tube will result in a frame that is torsionally softer. Think of a twisted frame with the top tube and down tube out of plane. A shorter head tube is torsionally stiffer than a long head tube and will resist this kind of flex. The closer the top tube is to the down tube where they connect to the head tube, the stiffer the frame (all other things being equal). Adding spacers will achieve a taller geometry without affecting frame flex and handling. The worst affect of torsional flexing is in the handling of the bike where the wheels go out of alignment (head tube out of plane with seat tube) and the bike does not track well. This makes sense. So in other words, what people/companies refers to as "relaxed geometry" is actually one that is a torsionally less stiff frame. Then the issue here is, why would it be considered to be more comfortable? By comfortable I would have assumed its more vertically compliant. Frames in this category include Giant's OCR range, Specialized Roubaix range etc. -- Not really. Geometry only affects rider position and handling dynamics. "Relaxed" generally means slacker tube angles to get the rider's weight back and slow down steering. Any shaped frame can be built to varying degrees of torsional stiffness, and vertical compliance is a myth. The trend of adding taller head tubes is purely for people who want higher bars without spacers. |
#10
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How real is a tall head tube to ride?
On Wed, 16 Apr 2008 11:27:40 GMT, Artoi wrote:
In article , "Phil Holman" piholmanc@yourservice wrote: "Artoi" wrote in message ... With Paris-Roubaix, everyone's talking about the value of "relaxed" frame geometry again, specifically the long head tube and the benefits they bring. My question is, what ride differences are there b/n a frame with a longer head tube and a regular road frame that has more spacers inserted below the stem, thereby achieving a longer virtual head tube? I've asked this question a number of times elsewhere and no one seemed to be able to answer it directly. -- I've never ridden cobbles very far but for normal road riding a longer head tube will result in a frame that is torsionally softer. Think of a twisted frame with the top tube and down tube out of plane. A shorter head tube is torsionally stiffer than a long head tube and will resist this kind of flex. The closer the top tube is to the down tube where they connect to the head tube, the stiffer the frame (all other things being equal). Adding spacers will achieve a taller geometry without affecting frame flex and handling. The worst affect of torsional flexing is in the handling of the bike where the wheels go out of alignment (head tube out of plane with seat tube) and the bike does not track well. This makes sense. So in other words, what people/companies refers to as "relaxed geometry" is actually one that is a torsionally less stiff frame. Then the issue here is, why would it be considered to be more comfortable? By comfortable I would have assumed its more vertically compliant. Frames in this category include Giant's OCR range, Specialized Roubaix range etc. The longer head tube causes the front triangle to not be a triangle. Instead of having all tubes in tension/compression they are more in flexion. How big a difference, probably not a hell of a lot. Enough to tell? Take that up with the propellor heads who think that as long as it has pneumatic tires no change in frame design could possibly make a difference. |
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