Weight on Bike vs Weight on Body

[amator]

I have found climbing much easier carrying two full 750ml Bottles in my rear jersey than the 2 bottles on the bike... any thoughts?

[dd74]

Weight on your body is easier to comply with than on the bike because the bike is fluid -- you have to make it move. The more weight there (on the bike) the harder it is to move (that is uphill).

I don't know. Just a guess.

[Dave]

Totally your imagination. You can put the water bottles anywhere you want. You still need the same amount of extra power to get them up a hill.

[William]

Out of sight, out of mind. :)



William

[paczki]

If you stand it would move the weight up and forward, very slightly changing the center of gravity to your advantage. Maybe. I dunno. Probably not.

[Pete Serotta]

Weight is weight as DAVE said - unless it is in the wheels....


Out of sight, out of mind. :)



William

[MattTuck]

Totally your imagination. You can put the water bottles anywhere you want. You still need the same amount of extra power to get them up a hill.

And if you stand up, you are likely exerting EXTRA energy to lift those two bottles. That's energy you would not have expended had you left them on the frame.

[RPS]

Weight is weight as DAVE said - unless it is in the wheels....
I respectfully disagree with you and Dave; there can be one important technical difference between “ADDING” weight to the bike versus to your body.

When standing to climb a very steep grade and there isn’t enough gearing available to turn the pedals over effectively, having the weight on the body helps in the ability to generate additional down force for a given amount of pulling upwards on the opposite pedal (assuming everything else equal like pulling up on bars).

Of course this assumes a rider who can push down on a pedal with far more force than he can pull up, otherwise it doesn’t matter. When almost stalled on a 20 % grade with a 39/23 gear every bit helps. I’d put the bottles in my jersey pockets and hope I don’t fall over. ;)


Regarding amator’s “much easier”? Any difference has to be pretty small considering the weight of two bottles compared to a human body.

[soulspinner]

Havent you been watching the pros? Youre supposed to throw the bottles in the grass when the road points up.......... :)

[Dave]

RPS...

Now all you have to do is prove that the added weight, when pedaling standing, causes a power increase that is greater than that required to move the bottles up the hill.

Somehow I think that if this was true, we'd see the pros moving bottles from the frame to their jersey pockets during a big climb, or at least before an out-of-the-saddle attack.

Instead of a doping scandal we should see riders disqualified for carrying too many water bottles or stuffing big rocks in their pockets. I can see it now - fans handing riders some rocks or extra bottles and yelling "fly like the wind".

[bluto]

Nonsense.................it's all in your head.

[zap]

I prefer to keep liquids in a bottle on the bike.

Never liked humps filled with liquid and carrying bottles in the jersey sucks. Done that many times and am always happy when I drank and sweated enough liquids to empty the pockets.

[TAW]

Weight is weight

Which one is more likely to get up the hill: a 100 pound man pushing a 200 pound cart or a 200 pound man pushing a 100 pound cart?

Discuss. :)

[RPS]

RPS...

Now all you have to do is prove that the added weight, when pedaling standing, causes a power increase that is greater than that required to move the bottles up the hill.

Somehow I think that if this was true, we'd see the pros moving bottles from the frame to their jersey pockets during a big climb, or at least before an out-of-the-saddle attack.

Instead of a doping scandal we should see riders disqualified for carrying too many water bottles or stuffing big rocks in their pockets. I can see it now - fans handing riders some rocks or extra bottles and yelling "fly like the wind".
What does that have to do with anything?

No, what YOU need to do is go back and read my reply as it relates to the question that was actually asked in the OP, not the one you are now making up about pros or who the hell knows.

By the way, did I state anything about generating additional “power”? I don’t think so, did I? I simply stated that under some conditions carrying the weight on the body may facilitate being able to generate additional force on the down stroke so that one doesn’t fall over as easily when climbing very steep grades with limited gearing. Obviously this doesn’t apply to pros and I see little connection to bringing them up in this discussion – particularly to challenge my reply.

Additionally, the question was not about whether carrying additional weight is good or bad, was it? The question assumed one has to carry the weight ANYWAY and it’s only a matter of whether one puts it on the bike or back pocket.

Can there be a difference? Absolutely. Is it always to the riders' advantage? No again. But that wasn't the question.


Dave, with all due respect, if you want to argue for the sake of arguing go and piss someone else off, because I’m not going to argue with you when you conveniently act like you don’t know the difference between forces and power when it suits you to pick a fight. And unless amator is a pro, let's leave them out of it.

[William]

Which one is more likely to get up the hill: a 100 pound man pushing a 200 pound cart or a 200 pound man pushing a 100 pound cart?

Discuss. :)


Ratio of dead weight to active weight.


:beer:

William

[RPS]

Which one is more likely to get up the hill: a 100 pound man pushing a 200 pound cart or a 200 pound man pushing a 100 pound cart?

Discuss. :)
Glad to see someone sees a difference. :beer:

[William]

Which one is more likely to get up the hill: a 100 pound man pushing a 200 pound cart or a 200 pound man pushing a 100 pound cart?

Discuss. :)


What’s the difference between a 200 pound guy who moves his bottles around, and a 100 pound guy moving his bottles around? Does it change anything for either guy? Or should they both go on a diet, lose 7 or 8 pounds and forget about the water bottles? :)




William

[Dave]

RPS...

I guess I misunderstood the brilliance of your reply. I thought that more force might equate to more power. I've personally never been in a situation where I was about to fall over from not having enough gear. Nor have I ever needed to pull up on the bars to get over a hill.

[Pete Serotta]

:) disagreeing is good..... lets go riding!! :bike:

I respectfully disagree with you and Dave; there can be one important technical difference between “ADDING” weight to the bike versus to your body.

When standing to climb a very steep grade and there isn’t enough gearing available to turn the pedals over effectively, having the weight on the body helps in the ability to generate additional down force for a given amount of pulling upwards on the opposite pedal (assuming everything else equal like pulling up on bars).

Of course this assumes a rider who can push down on a pedal with far more force than he can pull up, otherwise it doesn’t matter. When almost stalled on a 20 % grade with a 39/23 gear every bit helps. I’d put the bottles in my jersey pockets and hope I don’t fall over. ;)


Regarding amator’s “much easier”? Any difference has to be pretty small considering the weight of two bottles compared to a human body.

[goonster]

Nor have I ever needed to pull up on the bars to get over a hill.
Do you ride a recumbent?

[TAW]

What’s the difference between a 200 pound guy who moves his bottles around, and a 100 pound guy moving his bottles around? Does it change anything for either guy? Or should they both go on a diet, lose 7 or 8 pounds and forget about the water bottles? :)




William

Yes, you are correct, I wasn't necessarily responding to the water bottle scenario as much as RPS's comment. To save weight on training rides, I have my wife drive along beside me with a big gulp and an extra long straw so I don't have to carry any water. :D

[amator]

Its not a scientific experiment..... but like to say the bottles were snug and not causing undue discomfort, i was hoping for a placebo effect but it was a pleasant surprise to say the least and its not something Id do every day.

To put things in perspective, I have a friend who now carries a camelbak with 2 liters of water plus his mini lap top, some food, walking shoes that originally used to be in panniers on his bike. We are looking at probably 4-5 kilos off the bike that is snugly on his back now.

So would the naysayers still contend that even in this case , it makes nary a difference? :no:

[John H.]

It makes no difference with respect to power vs. weight.
I am guessing the difference is the higher weight makes you ride with less side to side motion.
I always thought that doing out of saddle climbing with a backpack (I commuted for many years) forced me to climb better. If you have a bunch of side to side movement with a pack on- you will really flail.

Its not a scientific experiment..... but like to say the bottles were snug and not causing undue discomfort, i was hoping for a placebo effect but it was a pleasant surprise to say the least and its not something Id do every day.

To put things in perspective, I have a friend who now carries a camelbak with 2 liters of water plus his mini lap top, some food, walking shoes that originally used to be in panniers on his bike. We are looking at probably 4-5 kilos off the bike that is snugly on his back now.

So would the naysayers still contend that even in this case , it makes nary a difference? :no:

[1centaur]

Engineers vs. artists, the eternal debate (not that engineers vs. engineers is any easier).

I submit that your legs resent what they are pushing more than what they are supporting with the help of arms on the bar and other skeletal elements.

[Ozz]

...When standing to climb a very steep grade and there isn’t enough gearing available to turn the pedals over effectively, having the weight on the body helps in the ability to generate additional down force for a given amount of pulling upwards on the opposite pedal (assuming everything else equal like pulling up on bars).....
If my own body weight (180 lbs) is insufficient to turn the pedals over on a steep hill, an additional 2 - 4 lbs isn't going to matter much. :cool:

I am also thinking of some physics laws about the conservation of energy....IIRC, you would need energy to lift the bottle to height where it would actually assist on the 'downward' part of the pedal stroke. Since this energy would need to be equal to or greater than the potential energy of the bottle, the net effect is essentially zero...

I am sure I'm mixing up terms and such....sorry, I was a business major with just a some organic chemistry thrown in for fun.

:beer:

[chuckred]

If you're carrying weight on your body - let's say on your back in a hydration pack or in your jersey pockets, it's putting more pressure on your seat, and possibly your arms (in the case of a pack). The additional pressure on your seat, over the course of a long day will cause more discomfort, and possibly also cause less efficiency as you move around trying to ease the pain.

On a long ride with a pack, the extra weight is pushing on your arms all day, as well as neck and core muscles. Again, this can't be good for overall efficiency.

For mountain bike endurance races, I've really been trying to minimize weight on my body vs. bike, and it's been helpful, at least in the way I feel at the end of the day. Although, the hike-a-bike portions may become more difficult I guess...

[rugbysecondrow]

Which one is more likely to get up the hill: a 100 pound man pushing a 200 pound cart or a 200 pound man pushing a 100 pound cart?

Discuss. :)


I'm 231 right now...I'll take that challenge. Lets find us some 130 pounders and do this.

;)

[Tobias]

Engineers vs. artists, the eternal debate (not that engineers vs. engineers is any easier).

I submit that your legs resent what they are pushing more than what they are supporting with the help of arms on the bar and other skeletal elements.
Reminds me of the old joke about arguing with an engineer is like wrestling with a pig in the mud …. after a while you realize he enjoys it.

Technically all weight is not the same. Never has been, never will be.

Sometimes where the weight is doesn’t matter. Other times it shouldn’t matter. And sometimes it can indeed matter; depends on how the question is interpreted and the context of what the weight does or can do (i.e. – how it affects other things).

In this case it doesn’t affect power requirement because the weight is the same so as long as the rider produces the same watts he will have the same speed up the hill.

In the example RPS framed where there isn’t sufficient force to go up a very steep climb and the rider risks coming to an unwanted stop, the weight on the rider could be a benefit … or not. If his legs are really strong and the weight allows him to push down easier it would be a plus. If on the other hand his legs are weak and standing is difficult on its own, then adding weight in the form of water bottles or camel back may hurt more than help.

There is no right answer here. If amator thinks he can climb easier with bottles on back that’s the only thing that “should” be important to him.

[rugbysecondrow]

If my own body weight (180 lbs) is insufficient to turn the pedals over on a steep hill, an additional 2 - 4 lbs isn't going to matter much. :cool:

:beer:

Seriously, are these water or cement filled bottles?

To Amitor, I would advise your friend that he might experience lower back pain if there is too much weight in a pack with his back at a wrong angle. I herniated a disc this summer doing that, and it wasn't even much weight. It don't know if it is or isn't more efficient, but I think the pannier and racks were invented for a reason.

[dogdriver]

This thread is precious.

Reminds me of yesterday at the local photo finisher, standing there watching the owner and his chief technical guy arguing over how my prints were going to be processed. After confirming that I wasn't paying the hourly ($100!) rate for technical consulting, I sat back and enjoyed the fight.

FWIW, all of the good mountain bikers I know use bottles in cages on the frame. I wear a Camelback.

My $.02, Chris

[Tobias]

If my own body weight (180 lbs) is insufficient to turn the pedals over on a steep hill, an additional 2 - 4 lbs isn't going to matter much. :cool:

I am also thinking of some physics laws about the conservation of energy....IIRC, you would need energy to lift the bottle to height where it would actually assist on the 'downward' part of the pedal stroke. Since this energy would need to be equal to or greater than the potential energy of the bottle, the net effect is essentially zero...

I am sure I'm mixing up terms and such....sorry, I was a business major with just a some organic chemistry thrown in for fun.

:beer:
I think we are all in agreement that 2 to 4 pounds isn't going to make a huge difference when the rider and bike weigh 200 pounds. Rick and others have correctly mention that. However, this question can be answered as a "theoretical" exercise based on very small incremental changes. It's no different that estimating how much slower a 200 pound guy will climb if he gains 2 pounds. It's a small difference but it's there.

As far as energy (efficiency) or ability to generate power I wouldn't even start to claim that it would make much difference. Not only that, but we can't know whether it would help or hurt in the climbing process. There are too many variables, but lifting the weight up and letting it come down again is not one that should make much difference. The rider puts energy into the water weight when lifting it, but then that weight does work on its way down.

[Tobias]

RPS...

I guess I misunderstood the brilliance of your reply. I thought that more force might equate to more power. I've personally never been in a situation where I was about to fall over from not having enough gear. Nor have I ever needed to pull up on the bars to get over a hill.
Are you serious?

May I suggest that if you've never come close to that feeling that maybe you are gearing your bikes too low to make riding as interesting as it can be. There is nothing better that getting to that spot where you are going so slow you know you can't stop and yet you are not sure you can make it. It's a rush. Honestly, you should try it.

[Ozz]

How about, if I drink my bottles empty before a climb?

Bottles are empty, but the water is sitting in my gut....until I sweat it out (or puke it out), I don't think it will help my speed up the hill. :p

:beer:

[tch]

I'm an English professor, so no particular knowledge of physics, math, or engineering. However, I do know "feel". Whether I can defend the reason or not, I feel weight on my bike more acutely than the weight on me. Lately, I've gone to wearing a Camelback for long rides instead of carrying two 24 oz bottles. Dorky -- perhaps. But the bike feels lighter, more alive under me when I take off the extra weight.

If weight makes no difference whatsoever, why does everyone try to get
their bike to the lightest weight possible? There's no question that we can feel the difference b/w a 16 lb bike and a 19+ lb bike.

[Tobias]

I'm an English professor, so no particular knowledge of physics, math, or engineering. However, I do know "feel". Whether I can defend the reason or not, I feel weight on my bike more acutely than the weight on me. Lately, I've gone to wearing a Camelback for long rides instead of carrying two 24 oz bottles. Dorky -- perhaps. But the bike feels lighter, more alive under me when I take off the extra weight.

If weight makes no difference whatsoever, why does everyone try to get
their bike to the lightest weight possible? There's no question that we can feel the difference b/w a 16 lb bike and a 19+ lb bike.
You are feeling a real difference; it is not your imagination.

A small weight difference in total bike-plus-rider weight can be a considerable percentage if applied exclusively to the bike. The same weight difference when applied to the rider (who can be 10 times heavier than his bike) will be almost imperceptible.

The bad news is that regardless of how the bike may “feel” extra light your climbing speed is mostly a function of your total bike-plus-rider weight. The bike may feel more alive making you feel faster, but to make a real difference you have to reduce the total weight, not just shift it around.

As to those who invest heavily in lighter bikes, the perception is greater than the reality for the reason noted above.

[McQueen]

Unless your water bottle cages are mounted to the end of your cranks or your rims, it should make no difference whether the water is attached to your body or your bike or in your gut. Rotating weight is another animal.

Now, aside from my aforementioned belief about this question, I would love to believe that the weight of the bike is more important that the weight around my midsection.

It would do so much for my justification of spending obscene amounts of money on lightweight bike stuff over the years to save 10 grams here and there, vs. losing it on my body.

[palincss]

When almost stalled on a 20 % grade with a 39/23 gear every bit helps. I’d put the bottles in my jersey pockets and hope I don’t fall over. ;)


A gear lower than 44.6 inches helps, too! :D

[RPS]

A gear lower than 44.6 inches helps, too! :D
Yeah, no doubt about it.

It actually happened to me years ago when I traveled to California to visit my daughter and only had my Calfee which I had picked up at Interbke after the show. The bike had a 39/23 low gear and I had no other parts for the 10-speed drivetrain. Anyway, some guys in the bike club where she worked told me about the Mt. Whitney Portal road climb and I decided to give it a try. I figured that if it got too bad I’d walk.

Near the top and after nearly 2 hours of climbing there is a short stretch that goes up around 20 percent which took me down to about 3 MPH or so. To keep from stalling and falling over (and to avoid walking at all since I’d already made it that far) I relied on pulling up on the opposite pedal as much as I could manage – which injured muscles around both ankles and feet. One of the dumbest things I’ve done “intentionally” on a bike.

In that case I would have gladly removed weight off the bike and carried it on my body. That’s what led me to think of the exception of all weight not being the same that I brought up earlier.

[palincss]

Near the top and after nearly 2 hours of climbing there is a short stretch that goes up around 20 percent which took me down to about 3 MPH or so. To keep from stalling and falling over (and to avoid walking at all since I’d already made it that far) I relied on pulling up on the opposite pedal as much as I could manage – which injured muscles around both ankles and feet. One of the dumbest things I’ve done “intentionally” on a bike.


Apropos of which,

To die is to be a counterfeit, for he is but the counterfeit of a man who hath not the life of a man; but to counterfeit dying, when a man thereby liveth, is to be no counterfeit, but the true and perfect image of life indeed. The better part of valor is discretion, in the which better part I have sav'd my life.

-- Henry The Fourth, Part 1 Act 5, scene 4, 115–121

[lemonlaug]

say you're going uphill seated, and you want to simultaneously stand and accelerate. With the bottles in on your bike, we can all agree that it's the same muscles you need to accelerate your bike that also have to accelerate the bottles. If you're sitting or standing already this is true for bottles in your jersey too, but WHILE standing the weight of those bottles is being moved by different muscles perhaps.

Think of it like this, if you threw your bottles in the air and then accelerated, your acceleration would feel initially different. Of course, as many have noted here, IT DOESN'T matter, because you'd have to catch them and whatever benefit you may have gotten you'd have to give right back (unless, you're a pro), but it would certainly feel different.

I'm not saying that's what's going on, but, as a thought experiment it works. I for one don't worry about it, I leave my bottles in the cages and I ride how I want. If I'm not going fast enough I don't ever let "two full bottles" supercede "just not fast" on my list of reasons why.

[Peter B]

Should I shift the lint from my navel to my jersey pocket on really steep climbs?

If you want to climb better, climb more. Quit gazing. Climb. With your bottles. Full.

Next topic please!

[paczki]

No less a rider than Jacques Anquetil used to shift his bottles to his jersey pockets on climbs. Why not :beer:

[johnnymossville]

Before starting a steep climb, Fausti Coppi used to take the water bottles out of their cages and put them in his back pockets to save weight.

[johnnymossville]

No less a rider than Jacques Anquetil used to shift his bottles to his jersey pockets on climbs. Why not :beer:

Ahhh, Anquetil. I thought Coppi. LOL glad you fixed it.

[Dave]

They used to smoke cigarettes to clear their lungs too. :rolleyes:

[salem]

First, I agree, the weight of a couple water bottles is a minimal percentage of the rider's weight, and therefore this probably won't make so much of a difference, but in absolute terms, I am convinced it does.

Here's why: First lets look at the more recent and progressive theories about bike fit. They move away from simply looking at body geometries and start to look at distribution of mass in the body as well. The reason being, according to physics, when you push down on the pedal, one of two things can happen: the pedal goes down or you go up. Ok, so you've never pedaled yourself off the saddle, but that is because when this starts to happen, you automatically use other musculature (your upper body, pulling on the bars, etc) to oppose the force that is trying to push you off the saddle. If this is a new and interesting idea, read Keith Bontrager's article about fit and KOPS.

Still with me? Get back to the fit idea, now people are looking at positioning the mass of the rider so it, when combined with gravity, most effectively opposes the force trying to push the rider off the saddle. So, unless you position added weight exactly at the riders center of mass (and actually, jersey pockets are probably pretty close to that), it will affect how well the rider's weight is fit to the bike.

Case in point, I've ridden a number of times with a heavy messenger bag (20-30 pounds) which hangs off the back of my butt when on the bike. I weigh about 140#, so that 20-30 is 14-21% of my weight, and without a doubt, my bike position never feels right with than heavy a bag cantilevered out behind me.

One last thought: watch some very good riders climb standing (Contador is an excellent example). You'll see some of them bouncing up and down, their whole body, including (most importantly) their hips. What they are doing is using their musculature to raise their body weight and then dropping it onto the down pedal stroke with closer to a locked leg. It takes a while to get used to the rhythm, but it can be a great asset because it uses different muscles than normal push-down pedalling, and when done right, really relaxes the upper body despite when looks like a lot of movement. Back to the the jersey water bottles, the added weight moving up and down would change the dynamics of the bouncing pedal stroke: more effort to lift, but then more weight to drop down.

So, I'd say it does matter, but as to just how much, I don't venture a guess.

[1centaur]

For all those focused on speed, the OP talked about feeling easier. Different stuff. I was serious about the arms and back sharing the pocket load with the legs when climbing out of the saddle and somewhat bent over. I think the legs know when they are pushing more vs. carrying more. How that knowledge plays into psychology, muscle recruitment, etc. is way beyond the analyticcycling approach to weight/power/speed. There's probably also psychology around moving the bike back and forth while standing, lighter being easier. Seated, maybe not.

[Lifelover]

And if you stand up, you are likely exerting EXTRA energy to lift those two bottles. That's energy you would not have expended had you left them on the frame.


This maybe only serious response that has made any sense.

Theoretically, if you go from sitting to standing allot, the water bottles in your pocket present more work. If you stay seated, there would be no difference.


Practically, Get Fn Life!

[false_Aest]

Isn't this about the time when TiDesigns should chime in?

[Ti Designs]

Ride first, reply later...

One thing to think about - is it just the weight or is it the movement of said weight? Let's look at two cases:

Case #1 weight on the bike: Let's say you put a 5 pound weight on the bike, in the first test case you put it on the bottom bracket, then you ride up a hill out of the saddle. As you swing the bike the radious from the ground to the bottle times the amount you swing the bike is how much the weight moves side to side, and it's velocity from a dead stop at the end of it's swing to it's full speed and back to a dead stop - this all takes energy. Now look at the same model with the weight moved up to the top tube. The radius has gotten much larger, thus the energy needed to swing it is greater - and it's wasted energy in terms of moving the bike forward.

Case #2 dead weight on the body: My bike can hold my water bottles all day long (in fact, it does). In theory, so can my body. But there's a difference, a body uses muscles to support weight. Muscles under strain don't get blood flow, so it's not exactly like your bike holding up your bottle. Take a full water bottle, hold it straight out in front of you for a few minutes, then tell me how little energy it takes...

Two cases, mechanics and biomechanics. At some point technique comes into it as well, but right now I have to go on a ride.

[rockdude]

Ok, to bring my bike for 18 pounds to 15 pounds, it will cost about $3000 + for the three pounds. Or I could do two weeks at the local weight loss center which would cost $200 for the three pound.

Am I correct to believe (for the most part) the net result in speed/power/climbing would be the same?

[1centaur]

You'd be very weak after the weight loss, and when you yo-yo'd back up you'd have lost your investment, whereas a light bike will stay light forever.

Forever's expensive.

[Climb01742]

Forever's expensive.

true dat. see diamonds. see alimony.

[djg]

Weight is weight as DAVE said - unless it is in the wheels....

or accelerating toward your forehead

It's hard to see how it matters much. Even smooth, in-the-saddle climbers might rock a bit, and might stand here and there -- seems to me the most likely disadvantage of having significant weight on the back -- say, in your pockets -- is that it might be a little less stable than you'd like; and noticing that might throw you off your rhythm a bit (which is likely to outstrip the extra work you'd do stabilizing yourself). Or it feels nice and cool against your back and you like that. Or not.

Wheels, accelerating -- sure, you'll feel light wheels (or the difference in switching to them).

In the end, either you push the rock up the hill or it stays at the bottom. If you know the size of the hill and the mass of the rock, you can figure out how much work you have to do.

[Ti Designs]

Ok, to bring my bike for 18 pounds to 15 pounds, it will cost about $3000 + for the three pounds. Or I could do two weeks at the local weight loss center which would cost $200 for the three pound.

I look at it the other way around. I'm now down under 150 and just starting base mileage. My bike on the other hand is 25 pounds of cross tired fixed gear. I ride with people on their road bikes and keep up just fine. It would take a lot of effort for them to get faster and stronger, but for me to drop 6 or 7 pounds off my bike is just a matter of taking the bike on the next hook over - that's easy!

[Tobias]

No less a rider than Jacques Anquetil used to shift his bottles to his jersey pockets on climbs. Why not :beer:
Before starting a steep climb, Fausti Coppi used to take the water bottles out of their cages and put them in his back pockets to save weight.

I don’t know if this actually occurred but it wouldn’t surprise me at all if it did. If a young strong-as-an-ox elite racer can push down on the pedals with more force than the bike can instantaneously accelerate forward due to its mass and also due to climb slope, the likely result will be that the rider will accelerate momentarily in the “up” direction. The lighter and the stronger the rider is the more he will be limited by his own weight – or lack thereof. Obviously he could pull up on the bars with more force (assuming he can), but that takes effort also.

Placing bottles in the rear pockets versus leaving on the bike doesn’t change total weight but it does marginally allow the rider to push down on the pedals with a little more intensity. Three or four pounds may not seem like much compared to a 130 pound climber, but in a sport decided by seconds any advantage may make a difference.

[Ray]

I hadn't looked at this thread, thinking it was one of those "lose weight or buy a lighter bike" discussions, but it was going on so long I figured I'd check it out. Most of you know that I'm about as far from an engineer as you can get, so I'm replying based on perception, not based on anything quantifiable. And I ultimately think 1Centaur's right that its mostly about feel, not actual difference in speed or power. If you move the bottles to your pockets before standing to climb, I can't believe that the weight they impart on the downstroke really does more than counter the extra energy it took to raise them on the upstroke. But I'll leave the formulas to the engineers.

In terms of feel, I used to commute to work by bike (now I walk from bedroom to office, kitchen to office, etc) and carried varying loads on various bikes. And what I learned was that any way you cut it, carrying MUCH extra weight made climbing more work. Up to 5-10 pounds I could carry in a messenger bag or in a saddle bag and nothing felt very different between carrying it on the bike or the back. But when it got heavier, things changed. At 20+ pounds, when I'd carry the load on my back, the bike still felt flickable and light underneath me, and easy to rock back and forth while climbing. But gearing was important - with big gears I REALLY felt the extra weight in my knees and legs from all of the lifting and supporting. The extra weight it imparted on the downstroke was less obvious than the extra work of keeping it all stable and lifting my (and its) weight on the upstroke. When I moved the weight to the bike, the bike felt a lot less lively, but I generally did this on more touring type bikes which felt less lively anyway. These were not fun bikes to ride out of the saddle much and were much less fun with lots of weight in panniers or a saddle bag. But I generally had very low gears on these bikes, so I could sit and spin an easier gear, which was perhaps a bit slower but a lot easier way of getting the weight up the hill.

I remember a few times carrying big weight (a couple gallons of milk plus other assorted groceries) in a big messenger bag on a fixed gear. There was one decent little hill between the grocery store and home and it was much easier getting up that hill with the weight on the bike than on my back. But again, gears come into play because on the bikes that had accommodation for putting the weight on the bike, I had low gears. On my fixie, I always carried stuff on my back and it obviously didn't have any low gears. And it was a real struggle getting up that hill with lots of weight on my back, with all of the lifting and rocking I had to do.

All this really tells us is that you should have low enough gears to climb what you're gonna climb with the weight you're gonna carry. But carrying a lot of weight on your body sure doesn't make things easier. The bike may feel lighter and more flickable, but once you feel burdened enough with the weight on your back, that flickable feeling is gone. With the weight of a couple of water bottles, I can't believe it matters at all.

For what little its worth,

-Ray

[RPS]

If you move the bottles to your pockets before standing to climb, I can't believe that the weight they impart on the downstroke really does more than counter the extra energy it took to raise them on the upstroke. But I'll leave the formulas to the engineers.In my opinion we shouldn’t commingle work/energy/efficiency related issues with ability to exert greater force. These are not directly related and shouldn’t be discussed as one or they will cause a lot of communications-based disagreements. I contend that 3 or 4 pounds of additional weight carried on a strong rider may allow him to produce greater force; and probably greater power as well under some conditions (like when pushing a very tall gear on a steep climb). The “having to lift the weight up before it goes down argument” may be correct in the context that it may be less “efficient”, but pedaling efficiency (in a technical sense) is hardly an issue in many real-world cases. When pros climbed in the old days with lowest gears like 42/21 and with bikes that were much heavier than today’s, it is not unreasonable to expect that on steep grades they were at times spinning very slowly compared to their best-power-efficiency cadence. In those cases shifting weight from their bikes to their bodies (hence keeping total weight exactly the same) could in theory allow them to produce more power, and therefore climb faster. I’d also guess that once they got done with the steepest climbs they would move the bottles back from their jersey to the frame.

I remember a few times carrying big weight (a couple gallons of milk plus other assorted groceries) in a big messenger bag on a fixed gear. There was one decent little hill between the grocery store and home and it was much easier getting up that hill with the weight on the bike than on my back. But again, gears come into play because on the bikes that had accommodation for putting the weight on the bike, I had low gears. On my fixie, I always carried stuff on my back and it obviously didn't have any low gears. And it was a real struggle getting up that hill with lots of weight on my back, with all of the lifting and rocking I had to do. And is it possible (not knowing your specifics) that if you could have put the added 20 pounds of weight on your fixie instead of on your back that you may have not made it up the hill at all? ;) Basically your example is exactly what I had been looking for. In theory there is only so much additional weight a given rider can add to a fixie or single before he can no longer climb a hill by merely pushing down on the pedals (may be 50 pounds or 100 pounds, but eventually he'll stall). However, in theory as long as the rider is strong enough he/she should be able to carry any weight on his body up a hill that he can climb without a load.

For clarification note the paragraph above is all about being able to create enough force to overcome gravity on a steep hill and doesn’t address efficiency, work, or power directly. It’s strictly about whether a rider can “pedal” at all against an unusually high resistance.

[54ny77]

what's lighter: a frozen water bottle at the beginning of a summer ride, or just plain chilled water?

discuss.

:rolleyes:

[RPS]

what's lighter: a frozen water bottle at the beginning of a summer ride, or just plain chilled water?

discuss.

:rolleyes:
A frozen bottle. Anything else you'd like to know? :rolleyes: