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  1. #51
    Senior Member rebel1916's Avatar
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    It's a silly situation.

  2. #52
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    Quote Originally Posted by rpenmanparker View Post
    Actually answers to those questions did appear earlier in the thread. All weight is more or less the same on the bike with regard to climbing and cruising. All weight is the same on the bike with regard to acceleration (and deceleration) unless it is rotating which makes the weight more significant, and in that case the larger the mass average radius of rotation, the more important is the weight. So reducing wheel weight is more significant than reducing frame weight as far as acceleration is concerned because the wheel is rotating mass and the frame isn't. But a lighter hub is less important than a lighter rim because the hub is closer to the center of rotation. Similarly a lighter wheel is more significant than a lighter crank because of the difference in radii of the two rotating bodies.

    Rider weight is much more complicated an issue. Most simply you could just lump the rider in with the other non-rotation weight. But rider weight also relates to rider power, so it is not so simple after all.
    I understand what you are stating...BUT... if a filled water bottle is being carried in the back of a jersey or in the cage you are stating that since the total weight stays the same it will not matter...even though the bike iteself will be lighter with the water in the jersey.

    If 2 riders have a weight difference of 20 pounds and both race at the same level...They end up at the finish line at the same time. Does that mean that the lighter rider would be using a bike that is 20 pounds heavier... I know this sounds ridiculous but you stated that "all weight is the same in regards to climbing".. I am obviously exagerating here to make a point.

  3. #53
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    Quote Originally Posted by kenshireen View Post
    This is a hypothetical situation... the point being the weight is the same on both bikes...
    If both masses (rider plus bike and all add ons) were being towed up the incline by a rope attached to a car, only the rotating weight would make any difference to the force and power required to accelerate to a certain speed. But in real life the rider provides the motive force, so as I said, it is not so simple. Close but not quite. All the other stuff like empty and full water bottles, where the weight is on non-rotating parts, etc. is to no effect.

  4. #54
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    Quote Originally Posted by kenshireen View Post
    I understand what you are stating...BUT... if a filled water bottle is being carried in the back of a jersey or in the cage you are stating that since the total weight stays the same it will not matter...even though the bike iteself will be lighter with the water in the jersey.

    If 2 riders have a weight difference of 20 pounds and both race at the same level...They end up at the finish line at the same time. Does that mean that the lighter rider would be using a bike that is 20 pounds heavier... I know this sounds ridiculous but you stated that "all weight is the same in regards to climbing".. I am obviously exagerating here to make a point.
    That is obviously not a realistic situation. IF the total non-rotating and rotating weights are the same, the acceleration and climbing characteristics (sans aero effects) should be too. If a bike is under UCI approved weight, it can be "handicapped" with added on weight. Just like a race horse. If a 20 lb lighter rider rode a 20 lb heavier bike (non-rotsting weight) the results should balance out, strenght factors being equal, of course. How many more ways does it have to be said?

  5. #55
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    And just to recap (again), aside from the obvious exception about that which rotates, weight is weight. Ten lbs. of non-rotating weight, regardless of origin, has the same effect.

  6. #56
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    Upon rereading I see that OP was asking a somewhat different question than I answered. He was asking if two riders of identical abilities, one 20 lb lighter than the other, arrive at the finish line together, does that mean the lighter one was riding a 20 lb heavier bike? Who knows why one did better than the other. Small differences in weight give small differences in resistance to acceleration and climbing. Larger differences in weight would result in larger differences in acceleration and climbing speed. But to say that weight must make up differences between identical riders is a far stretch. There is aero both of the bikes and the bodies, there is technique and how it is applied on any given day. There is hydration or the lack thereof, and on and on. I think OP has good answers to his good questions and no real answers to his bizarre questions. IMO, that is how it should be.

  7. #57
    bt
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    stupid thread.

  8. #58
    Senior Member Homebrew01's Avatar
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    Quote Originally Posted by bt View Post
    stupid thread.
    1 of many
    Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike

  9. #59
    Senior Member lechat's Avatar
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    You really need to ride a sub 14lb bike to appreciate the difference. Performance metrics are meaningless. I have 1 of my bikes down to 13.05lbs, ready to ride, and it's a blast, especially with the local hilly terrain. Makes my 17lb Roubaix feel like a lead sled.
    hillbilly

  10. #60
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    Quote Originally Posted by lechat View Post
    You really need to ride a sub 14lb bike to appreciate the difference. Performance metrics are meaningless. I have 1 of my bikes down to 13.05lbs, ready to ride, and it's a blast, especially with the local hilly terrain. Makes my 17lb Roubaix feel like a lead sled.
    See, that's what I'm talkin' about, but some folks want to keep bringing it back to how many seconds can they save and wouldn't it be better to lose body weight. It is just not the same thing.

  11. #61
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    Quote Originally Posted by rpenmanparker View Post
    Upon rereading I see that OP was asking a somewhat different question than I answered. He was asking if two riders of identical abilities, one 20 lb lighter than the other, arrive at the finish line together, does that mean the lighter one was riding a 20 lb heavier bike? Who knows why one did better than the other. Small differences in weight give small differences in resistance to acceleration and climbing. Larger differences in weight would result in larger differences in acceleration and climbing speed. But to say that weight must make up differences between identical riders is a far stretch. There is aero both of the bikes and the bodies, there is technique and how it is applied on any given day. There is hydration or the lack thereof, and on and on. I think OP has good answers to his good questions and no real answers to his bizarre questions. IMO, that is how it should be.
    I think you missed my point.
    You had stated that total weight (Rider and bike) was what mattered (given the fact that rotational weigh is of utmost importance). The point I was trying to make was that if that statement was correct than a rider 20 points heavier riding a bike 20 pounds lighter..given the same ability, aerodynamics etc.... would end up together at the finish line with a rider 20 pounds lighter with a bike 20 pounds heavier.. Yes. it is an exaggeration but the principle is the same.

  12. #62
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    Quote Originally Posted by rpenmanparker View Post
    See, that's what I'm talkin' about, but some folks want to keep bringing it back to how many seconds can they save and wouldn't it be better to lose body weight. It is just not the same thing.
    so are you stating that if he lost 3 pounds of body weight, that riding the roublaix would perform like the 14 pound bike did when he was 3 pounds heavier. I think not

  13. #63
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    Let me Summarize with one simple quesiton

    Losing 3 pounds of body weight or losing 3 pounds of bike weight (assuming non rotational) has the same effect on the effort you have to expend.

  14. #64
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    Quote Originally Posted by kenshireen View Post
    Losing 3 pounds of body weight or losing 3 pounds of bike weight (assuming non rotational) has the same effect on the effort you have to expend.
    Yes, of course.
    Quote Originally Posted by kenshireen View Post
    so are you stating that if he lost 3 pounds of body weight, that riding the roublaix would perform like the 14 pound bike did when he was 3 pounds heavier. I think not
    I'm not sure what you are asking. Not sure what the Roubaix weighs. What you mean by "perform". But that is not the point. Energy required to climb a hill or ability to accelerate won't be affected by where the weight comes from. But no matter what the rider weighs, a lighter bike will feel different than a heavier bike.

  15. #65
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    Quote Originally Posted by kenshireen View Post
    I think you missed my point.
    You had stated that total weight (Rider and bike) was what mattered (given the fact that rotational weigh is of utmost importance). The point I was trying to make was that if that statement was correct than a rider 20 points heavier riding a bike 20 pounds lighter..given the same ability, aerodynamics etc.... would end up together at the finish line with a rider 20 pounds lighter with a bike 20 pounds heavier.. Yes. it is an exaggeration but the principle is the same.
    Yes.

  16. #66
    rugged individualist wphamilton's Avatar
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    Quote Originally Posted by kenshireen View Post
    Losing 3 pounds of body weight or losing 3 pounds of bike weight (assuming non rotational) has the same effect on the effort you have to expend.
    I haven't read the thread, but I don't agree with this. There is a metabolic cost to carrying more weight, and also a mechanical price to pay moving it around (over and above spinning the cranks), so other things being equal the three pounds on your body will consume more calories than three pounds on the bike. More energy means less available to pedal, which means less power.

  17. #67
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    Quote Originally Posted by wphamilton View Post
    I haven't read the thread, but I don't agree with this. There is a metabolic cost to carrying more weight, and also a mechanical price to pay moving it around (over and above spinning the cranks), so other things being equal the three pounds on your body will consume more calories than three pounds on the bike. More energy means less available to pedal, which means less power.
    True, but those arguing this issue sort of agreed to lump all that in "everything else equal". I agree with you but see how a simplification can be useful for understanding the basic question of does it matter where non-rotating weight is located.

  18. #68
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    Quote Originally Posted by rpenmanparker View Post
    True, but those arguing this issue sort of agreed to lump all that in "everything else equal". I agree with you but see how a simplification can be useful for understanding the basic question of does it matter where non-rotating weight is located.
    and from what I have gleaned from you well written posts... it does NOT matter where non-rotating weight is located; be it in your back pocket, or behind the seat or in your handlebars/stems etc.

  19. #69
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    Quote Originally Posted by kenshireen View Post
    and from what I have gleaned from you well written posts... it does NOT matter where non-rotating weight is located; be it in your back pocket, or behind the seat or in your handlebars/stems etc.
    "Let's go Tonto. Our work is done here."

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