Results 1 to 21 of 21
  1. #1
    mtbr member
    Reputation: nkrax's Avatar
    Join Date
    Nov 2004
    Posts
    175

    Losing x lbs. of bike weight is like losing x lbs of body weight...is there a number?

    Losing x lbs. of bike weight is like losing x lbs of body weight...is there a number?

    Is there a number that fits this equation? In other words, if your bike weighs 28 pounds and you trim it down to 25 pounds, is that the same as losing 3/5/7 pounds of body weight? Is there a correlation here?

    Thanks,
    nkrax

  2. #2
    mtbr member
    Reputation:
    Join Date
    Dec 2004
    Posts
    104
    All depends on the terrain.

    Once moving though - having big ears is more of an issue than having 10 pounds extra on the bike.

  3. #3
    Recovering couch patato
    Reputation: Cloxxki's Avatar
    Join Date
    Jan 2004
    Posts
    14,009
    On something like Alpe d'Huez, it doesn't matter where the weight is. Though with a 10lb body and a 200lb bike, it will be harder to keep the pedals turning.
    During the time that you're actually accelerating (not climbing!!), the weight on the outside of your wheels counts about double, though it will feel like tenfold.

    But better believe, lose 10lb from yourself, and you'll be kicking azz out on the trails. A buddy of mine has weight changes that are much bigger than mine. When he's in "winter" shape, it's a long wait on the top of a small hill. When he's lighter (not fitter), he can be a real handful for the weightweenie fitfukker me.

    In extreme cases, like a very fit body, but a lockedout 2x8" DH bike, the weight may hold you back getting over the trail easily. Just to note that a bike's weight should not kill your ability to handle it.

    If your riding demands you to bunny hop all over the place, obviously, a light bike will make things easier. 2kg of bike weight has always been a night-and-day difference to me on my lame trails, but never to be translated in true laptimes. The rider is just too big a factor, an offday, and I won't be fast on the fastest bike I can imagine. A fit day, and please give me a heavy bike so I can at least feel the pedals.

    Meirhaeghe won the 2003 Worlds on a heavy Specialized Epic that bopped like mad. And he was tested clean.
    Klok - XC - Skate - Ski

  4. #4
    banned
    Reputation:
    Join Date
    Apr 2004
    Posts
    2,997

    5 to 1

    Quote Originally Posted by nkrax
    Losing x lbs. of bike weight is like losing x lbs of body weight...is there a number?

    Is there a number that fits this equation? In other words, if your bike weighs 28 pounds and you trim it down to 25 pounds, is that the same as losing 3/5/7 pounds of body weight? Is there a correlation here?

    Thanks,
    nkrax
    is my gut feeling but I'm sure the scale changes for terrain.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    796
    I think I heard once that for every 146.2 lbs that you lose on your body, the same effect is realized when you shave a lb off your bike ...can anyone verify?

  6. #6
    mtbr member
    Reputation:
    Join Date
    May 2004
    Posts
    8
    Quote Originally Posted by eurorider
    I think I heard once that for every 146.2 lbs that you lose on your body, the same effect is realized when you shave a lb off your bike ...can anyone verify?
    that is just about how much I weigh. Does that mean that if I shaved a pound off my bike it would be like no one was riding the bike at all?

  7. #7
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    796
    Quote Originally Posted by lgoodwin
    that is just about how much I weigh. Does that mean that if I shaved a pound off my bike it would be like no one was riding the bike at all?
    good point

  8. #8
    Dr. Frost
    Reputation: Fastskiguy's Avatar
    Join Date
    Jan 2004
    Posts
    1,602

    What is a fitfukker anyway?

    I think a pound on the bike is the same as a pound on the body.

    Is it OK to say fitfukker in public?

  9. #9
    mtbr member
    Reputation: EBasil's Avatar
    Join Date
    Jan 2004
    Posts
    2,062
    I look at it more along the lines of what it would cost, in dollars, pain and inconvenience.

    I've concluded it's WAY CHEAPER to spend money on light parts than to forego the next slice of pizza.

  10. #10
    mtbr member
    Reputation: Halloween's Avatar
    Join Date
    Dec 2003
    Posts
    76
    Quote Originally Posted by Fastskiguy
    I think a pound on the bike is the same as a pound on the body.

    Is it OK to say fitfukker in public?

    Let's look at myself as an example. The last time I had a dunk test to determine body fat (I do a lot of guinea pig work for the exersice physiology dept at the university), I came up with 5.6 % body fat, and my upper body is not very muscular at all.

    I think if I lost any weight on my body (read muscle mass in my legs) it would be detrimental to my performance.

    Conversely, If one is 80 pounds overweight, loosing 5 pounds on one's bike will have a negligable effect on actuall overall performance.

    So, no, there is no number because it is very situation dependent.

    Which makes me wonder as a one who most often just lurks in this forum...

    How many regulars here put as much time and energy into making your body as well tuned of a machine as you do your bicycle?

  11. #11
    Jm.
    Jm. is offline
    mtbr member
    Reputation: Jm.'s Avatar
    Join Date
    Jan 2004
    Posts
    7,137
    Loosing weight on your bike means more because it is further away from the center of rotation. All things on your bike are constantly being accellerated, and the further the mass is from the center of your body, the more energy it takes to accellerate it. This is why going to a 23lb bike from a 30lb bike makes a HUGE difference, it's a big difference in the mass that is constantly being accellerated by your body.

    Mass that is ON your body does not affect this as much because it is closer to the center of rotation, which means to accellerate this mass, it takes much less energy.

    This is also why you can't hold a 20lb rucksack in front of you for more than a few minutes, yet you can strap it to your back and walk around all day long with it.

    Loosing weight on your body is a great thing, but from the standpoint of physics, it means more if everything else is constant to loose weight off of something further from the center of rotation, rather than closer.
    I know in my heart that Ellsworth bikes are more durable by as much as double. AND they are all lighter...Tony Ellsworth

  12. #12
    all hail der Fuhrer Bush
    Reputation:
    Join Date
    Mar 2004
    Posts
    1,635

    I believe you are correct

    Quote Originally Posted by Fastskiguy
    I think a pound on the bike is the same as a pound on the body.

    Is it OK to say fitfukker in public?
    I do not think there is any difference whether the weight is carried on the frame, in your back pocket, or waterbottle, or strapped under your saddle.
    Unless it is rotating weight. then the time honored axiom says "a pound on the frame is worth two on the wheels."
    Extrapolating from that, I would add "a pound on the frame is worth 1lb. 3 ounces on the pedals, or crank, or shoes; as these rotate, but much more slowly than the wheels.
    "Bicycling Science," Whitt & Wilson, local library, if you want to quibble about the 3 ounces. It well may be 2 ounces, or 4 ounces, but I'm willing to bet you a dollar to a cracked doughnut that my estimate is pretty close.

    Of course, less weight in the frame may result in more energy loss from increased frame flex, which might well more than cancel out the weight savings of a lighter frame.
    Don't pay the $85 fee to ride land you own! Resist!

  13. #13
    120 pounds of xc sex!
    Reputation: carbnjunkie's Avatar
    Join Date
    Aug 2003
    Posts
    639

    yup

    I agree with BulC. I had a friend who was obessed with getting the weight down on his dually, and he got it down to like 22.5 pounds, altho he was 30 pounds overweight....doesnt make that much sense
    Team X-poser is back for 2006-

    WTB; 1.25 inch tow rack in SoCal

    >Ankur<

  14. #14
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    796
    Quote Originally Posted by carbnjunkie
    I agree with BulC. I had a friend who was obessed with getting the weight down on his dually, and he got it down to like 22.5 pounds, altho he was 30 pounds overweight....doesnt make that much sense
    It doesn't make much sense to be 30 pounds overweight in the first place.

  15. #15
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    796
    Quote Originally Posted by Halloween
    Let's look at myself as an example. The last time I had a dunk test to determine body fat (I do a lot of guinea pig work for the exersice physiology dept at the university), I came up with 5.6 % body fat, and my upper body is not very muscular at all.

    I think if I lost any weight on my body (read muscle mass in my legs) it would be detrimental to my performance.

    Conversely, If one is 80 pounds overweight, loosing 5 pounds on one's bike will have a negligable effect on actuall overall performance.

    So, no, there is no number because it is very situation dependent.

    Which makes me wonder as a one who most often just lurks in this forum...

    How many regulars here put as much time and energy into making your body as well tuned of a machine as you do your bicycle?
    Well said ...I know that if I lose weight, it will also be detrimental to my performance. My weight tends to go up from physical activity.

  16. #16
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    1,396

    Damn man....

    Quote Originally Posted by Halloween
    I came up with 5.6 % body fat
    Eat a Pizza! 5.6% is outrageously low. I'll bet you absolutely scream up hills.

    Dave

  17. #17
    mtbr member
    Reputation: Lost81's Avatar
    Join Date
    Dec 2004
    Posts
    116
    160 lbs, 6' 2", 32.9" (83.57 cm) measured inseam here.
    I love, love, long hill climbs (in the thousands of feet elevation especially).

    My 6' 4.5" 300 lb housemate hates it though.
    He went riding with me once, quit after 20 minutes, and never went riding with me again.
    Hmm... I guess I should learn some empathy


    -Lost81

  18. #18
    On your left.
    Reputation:
    Join Date
    Jan 2004
    Posts
    1,174

    An easy test

    Quote Originally Posted by nkrax
    Losing x lbs. of bike weight is like losing x lbs of body weight...is there a number?

    Is there a number that fits this equation? In other words, if your bike weighs 28 pounds and you trim it down to 25 pounds, is that the same as losing 3/5/7 pounds of body weight? Is there a correlation here?

    Thanks,
    nkrax
    Many posters (not me, not yet) have training bike and a race bike. I'd like to know if there is any time difference between the two: climbing a hill, doing a long flat ride, doing a good local loop, doing a full race (could base difference on time interval to similar competitor - that's what it's all about anyway).

    I think it is more beneficial to shave 5lb off the bike than off the body because the body has to manipulate the bike around when riding. The hopping over stufff, lifting the front wheel, taking bumps, etc requires muscle/energy. So maybe a 30 minute lap will not show much difference, but over a race distance the fatigue adds up and I bet that last climb or sprint to the finish is not as lively and that is where races are won and lost.

    When you look at sprint athletes vs. endurance athletes the 2 big differences I see are age and lean. Sprint is generally young and very lean; Endurance is generally 25+ yrs and certainly fit, but not super lean. A little extra fat, maybe in the 7-9% range is maybe best to prevent energy dips over long intervals and not be totally dependant on fuel during the event.

    Of course loosing weight is generally good, but I think that is just a byproduct of reguar training and proper eating.

    Maybe nobody wants to know the answer because we enjoy building light bikes and like to assume it makes us faster. It is easier to live that way.
    M

  19. #19
    Jm.
    Jm. is offline
    mtbr member
    Reputation: Jm.'s Avatar
    Join Date
    Jan 2004
    Posts
    7,137
    Quote Originally Posted by bulC
    I
    Unless it is rotating weight. then the time honored axiom says "a pound on the frame is worth two on the wheels.".

    Don't you see though, it's all rotating weight basically, any time you accellerate your bike (which is happening constantly) there is going to be a center of rotation. You are constantly accellerating it, and that's why a heavy bike takes such a big toll on someone, even when the diff between it and a lighter bike is not that great.

    If I pedal, there is a center of rotation, if I move my leg forward, there is a center of rotation, if I turn my handlebars one way or the other, there's a center of rotation, etc...
    I know in my heart that Ellsworth bikes are more durable by as much as double. AND they are all lighter...Tony Ellsworth

  20. #20
    nightriding is fun !
    Reputation: Big Bad Wolf's Avatar
    Join Date
    Jun 2004
    Posts
    457
    Quote Originally Posted by nkrax
    Losing x lbs. of bike weight is like losing x lbs of body weight...is there a number?

    Is there a number that fits this equation? In other words, if your bike weighs 28 pounds and you trim it down to 25 pounds, is that the same as losing 3/5/7 pounds of body weight? Is there a correlation here?

    Thanks,
    nkrax
    It is assumed that each kilo of weight lost on your bike correlates to 7-8 kilos lost on you, not considering anything else (fitness levels etc).
    This has something to do with the assumption that your bike consists of 1/9th to 1/10th of your system weight
    Check Analytic Cycling to see how losing weight affects your performance
    Titanium or Bust !

  21. #21
    PeT
    PeT is offline
    Occasionally engagedů
    Reputation: PeT's Avatar
    Join Date
    Jan 2004
    Posts
    1,407

    Weight on body is more detrimental..

    Quote Originally Posted by nkrax
    Losing x lbs. of bike weight is like losing x lbs of body weight...is there a number?
    I agree that it's relative, but most folk are forgetting the physiological toll of excess weight, even if that weight is muscle. For instance, Lance Armstrong was always good, but he became great after losing 20 pounds of "useless" muscle. When you're teetering on the edge of an anaerobic pit on a long climb, that extra pound or two on your body still needs to be oxygenated and fed -- that extra pound or two on your bike does not. Yeah, a pound is a pound no matter where, but I'm not pumping blood through my seat pack or disc brake. I had the same fitness base two years ago, but this year my VO2 max actually climbed even though I was no more aerobically fit, simply because I weighed 5 pounds less. Even though Nino's bike is 5 pounds lighter than mine, I know losing those 5 pounds off my body made me faster than if I had simply switched to Nino's bike. Of course, doing both would be best, but if you're picking places to get rid of useless weight, the body has to come first.

    While I believe it's more important to lose body weight, I still love a light bike!

Similar Threads

  1. Mountain bike jargon/ lingo
    By bstguitarist in forum Beginner's Corner
    Replies: 20
    Last Post: 05-26-2005, 12:02 PM
  2. blast from the past, cut/paste from archived MTB DOC posts
    By ashwinearl in forum XC Racing and Training
    Replies: 12
    Last Post: 02-09-2005, 08:47 AM
  3. If you need to know this.
    By KevinVokeyJ24 in forum General Discussion
    Replies: 14
    Last Post: 12-24-2004, 08:40 AM
  4. POLL: What's your bike weight to rider weight ratio?
    By split in forum Weight Weenies
    Replies: 38
    Last Post: 06-10-2004, 08:29 AM
  5. The Official Weight Weenies F.A.Q
    By Trevor! in forum Weight Weenies
    Replies: 0
    Last Post: 02-25-2004, 12:31 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •