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I was discussing with my LBS owner whether or not losing 1 lb body fat (mine) would provide the same end results in performance for me as buying a bike that weighed 1 lb less? Of course, he believed that having a lighter bike would be more advantageous. What do you think?

I can understand that lighter wheels would make more of a difference due to the rotational dynamics involved, but just considering the weight of the frame, I can't see any difference between body weight and frame weight.
 

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Even wheel weight confuses many people

Physiologically, whether you're hauling down a flat road or up a hill, a pound is a pound is a pound. An argument could be made that if you're out of the saddle on a climb, a lighter bike would take less energy to rock back and forth, though that is rather weak as you are just balancing forces, not really swinging the weight of the bike. Even wheel weight is only different than other weight when you are accelerating. Once you're up to speed, it makes no difference where the weight is. Heavier wheels are harder to spin up to speed, but they give that energy back every time you coast, so there is no net penalty unless you hit the brakes and burn the extra kinetic energy as heat. Losing a pound by dieting is much less pleasant than buying a bike that is a pound lighter, but the effect is exactly the same. And as much as we all lust after light weight stuff, 1 lb. (454 gm) saved will improve your speed by about 0.045 mph/.072 kph on a 6% grade. That's 237 feet/73 meters after one hour of riding. The 21 second advantage is big news if you're in a bike race, but meaningless to the rest of us.
 

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Ask a Mechinacal Engineer

It is sprung versus unsprung weight. The argument behind a Camel Back is based on sprung weight being perceived as lighter than unsprung weight of water bottles attached to a frame.
 

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It's not all the same...

Just my 2 c worth, in general, lowering your weight by a lb is better than buying a lightweight bike. But that assumes 2 things 1) you can afford to lose the weight, and 2) it's frame mass we're talking about.

Wheels are a totally different story.....

Bacco said:
I was discussing with my LBS owner whether or not losing 1 lb body fat (mine) would provide the same end results in performance for me as buying a bike that weighed 1 lb less? Of course, he believed that having a lighter bike would be more advantageous. What do you think?

I can understand that lighter wheels would make more of a difference due to the rotational dynamics involved, but just considering the weight of the frame, I can't see any difference between body weight and frame weight.
 

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Loosing a pound of fat...

the correct way(exercise and proper diet) will increase your fitness level. This increase in fitness will be more valuable to performance than the change in weight. I think that if you lost the pound of fat and added a pound to the frame you would still be faster.

You stated the question as an either or situatoin. Either loose the weight or buy a lighter bike. The two are not mutualy exclusive. If you desire and can afford a lighter bike than go for it. If you can spare a pound of fat and are willing to work it off than do that too.
 

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An additional thought: when you get a new frame (or wheelset, or whatever) that eliminates a pound, you feel the weight drop immediately. You have instant contrast between yesterday's weight and today's weight, so the difference is perceived as larger. On the other hand, bodily weight loss is much more gradual (er, I hope you're not dropping a pound a day), so the difference would seem much less pronounced. So, ignoring any real physical differences, you'll think the frame loss is more effective.

It's kind of like growing a beard (you don't look any different to the people you see daily to weekly) versus shaving it off one morning (instantly unrecognizable to people you know).
 

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NeoRetroGrouch
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Only really valid for MTB...

Slip Stream said:
It is sprung versus unsprung weight. The argument behind a Camel Back is based on sprung weight being perceived as lighter than unsprung weight of water bottles attached to a frame.
or maybe CX. You have to be standing and keeping your body mass from going up and down with the bike. Not a lot of whoops road biking.

TF
 

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Off the body!!

A pound off the body is better than a pound off the bike. Dropping body weight has a direct impact on your measured VO2 max. Partly because the measured value is normalized to your weight (so somewhat of an artificial gain), but also because each pound of fat you have is a pound of metabolically active tissue that requires the vasculature to provide it with oxygen, glucose, etc... Get rid of that pound of fat, and you've now freed up oxygen, nutrients, etc... for the rest of your body, and also eliminated the vasculature that was supporting the pound of fat (which is less road for your blood cells to travel).

That said, a bike that is a pound lighter is much cooler looking, since it will probably have carbon fiber upgrades! :D
 

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Bacco said:
I was discussing with my LBS owner whether or not losing 1 lb body fat (mine) would provide the same end results in performance for me as buying a bike that weighed 1 lb less? Of course, he believed that having a lighter bike would be more advantageous. What do you think?
it is one of "it depends" questions. In majority cases loosing 1lbs of fat will be more beneficial. During exercise you loose ~200-350 fat Cal/hr, so 1lbs of fat is equivalent of 12-18hr of LSD. Benefit of 12-18hr of constant effort it will include higher aerobic power, lesser dependency on glycogen. You'd be able to go faster, ride longer. The exception will be if your fat % is optimal and can't be brought lower w/o sacrificing output. Of cause if you're a shop owner, it is more profitable for you if your customers take weight off their bikes.
 

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bike weight < body fat weight = poser

So, if you're world class, weight less than 180 lbs and are under 8% body fat you can ride anything. If you're in good shape, weigh 165 and are 11% body fat you can ride an 18 lb bike, but nothing lighter. If you weigh 210 and have 18% body fat, you can't ride any bike that makes any pretense of being light and need to find an old Schwinn Continental. These are absolute rules. Nothing looks worse than a flat fabby @ss on a 16 pound bike.
 

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Continental said:
So, if you're world class, weight less than 180 lbs and are under 8% body fat you can ride anything. If you're in good shape, weigh 165 and are 11% body fat you can ride an 18 lb bike, but nothing lighter. If you weigh 210 and have 18% body fat, you can't ride any bike that makes any pretense of being light and need to find an old Schwinn Continental. These are absolute rules. Nothing looks worse than a flat fabby @ss on a 16 pound bike.
I like your rules, but they break down at the upper end of the weight range. At 5'11" and 215, I think my 22 lb steel road bike is OK. Picture an older, larger gentleman on a super-clean 1972 Champagne brown Raleigh International, with a honey B.17. There's beauty there, admit it.

--Shannon, who will buy an International after he gets his Riv, in
San Diego, CA
 

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I know you said an lb of fat, but think about an lb of muscle. That lb of muscle is not just sitting there, like a lb of steel tubing. That lb of muscle is being used to power you up the hill.
Also, think 15 lbs. Do you really think you would notice 15 lbs of body weight more than a bike that weighted 15 more lbs?
 

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Definitely off the body.

I struggle with my weight and will testify that it's much easier to carry a load in panniers than to carry the same size load on my body.
 

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Absolutely...

Spoiler said:
I know you said an lb of fat, but think about an lb of muscle. That lb of muscle is not just sitting there, like a lb of steel tubing. That lb of muscle is being used to power you up the hill.
Also, think 15 lbs. Do you really think you would notice 15 lbs of body weight more than a bike that weighted 15 more lbs?
When I dropped 15 lbs, riding became a new experience. More aero, less pain (back, wrist, shoulder, etc) and better breathing plus the weight advantage.
TF
 

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A few observations

The obvious answer is: both! Barring that-

Rotating weight is king- dropping that makes the most difference of all, especially when climbing or doing most types of racing other then solo TT's.

You will notice dropping a pound of bike weight much more readily, because the percentage change is huge in comparison to dropping a pound of body weight. Honestly, the change for most non-world class althletes is pretty small when dropping a single pound. However, as I can attest personally, dropping 10 or more pounds has an astounding effect on your riding- 2-3 gears extra on hills. Note, the weight drop came over a season of riding and with lots of riding too. Barring that sort of drop, carving some lard off your bike will be more noticable, especially on hills, accellerations or sprints.
 

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Apples vs Oranges, uh, er, Fat vs Metal

It's easier to loose 40 pounds of fat than it is to loose 40 pounds of bike. ;)

Totally different measurements, see all the above remarks.

Perhaps a better question would be: Once you've reached a training or weight loss plateau, what are the benefits of paying for less weighty components vs getting a personal trainer and going to a training camp? The costs of both are probably very comparable.

Right now I've got more than a bike weight to loose, so bike weight is totally secondary.
You're personal situation will in "large" part depend on your own fat-quotient.
 

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Agreed. One pound of body weight is .05% of a 200lb person. No problem, and you will be fitter.

1 lb off of a 4lb frame is 25% and you are asking for trouble.
 

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Spunout said:
Agreed. One pound of body weight is .05% of a 200lb person. No problem, and you will be fitter.

1 lb off of a 4lb frame is 25% and you are asking for trouble.
But say 1lb off a 18 pound rig, to a 17 pound rig is easily do-able, and quite safe to boot (well safe to everything but your credit limit!)

Also, dropping a pound of water weight- not really helpful. Dropping a pound of muscle- not great either. Dropping a pound of lard- priceless! Heh.
 

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Are you sure?

"On the other hand, bodily weight loss is much more gradual"

If I'm not mistaken, most people can fluctuate pounds within a single ride... water, feces, urine... What did Lance lose in that one Mtn TT?... 6 lbs? Crazy. But Im gonna agree, that 1 pound of body mass is more important, your legs have to push it, your arms have to hold it up....
 

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Coolhand, read my post above

Simple physics will tell you that rotating weight is only meaningful when you accelerate. IOW, a pound of wheel weight is the same as a pound of water bottle weight at constant speed. If your speed is going up and down, then you take double the energy to accelerate the wheels (compared to non-rotating weight) but you get that energy back when you decelerate. Unless you're constantly braking, wheel weight is the same as other bike or rider weight when you average things out. This is a simple, physical fact, and not something that is debateable.
 
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