Bike Weight vs Body Weight ??

WornSaddle said:

Well, after about 30 years off I'm riding again and shopping for an updated bike (to replace mid 70's Raleigh Pro's). When I was racing I weighed about 130, by mid 40's I was 210 and several years ago I went down to 155 and now range between 157 & 167. So the question:

Is saving 3lbs of static non-rotating weight on a bike the same as reducing my body weight by 3lbs?

In other words, how much is it worth to have a 14lb bike rather than a 17lb bike when loosing 3 lbs is A LOT cheaper (namely free)?

Good question, if your new bike is reasonable and suites your requirements, I would assume loosing body weight would be the best focus.

Static mass is static mass.

steve said:

Good question, if your new bike is reasonable and suites your requirements, I would assume loosing body weight would be the best focus.

I would agree.

Unless, you are financially blessed.....money is no object.....you have great gobs of money to spend......

Then, buy that insanely expensive 14 pound bike and lose some body weight. You'll have the best of both worlds. 🙂

So If I lose the 30 lbs I need to, and my bike weighs 22, It will be like my bike weighs -8 lbs?

fatandslow said:

So If I lose the 30 lbs I need to, and my bike weighs 22, It will be like my bike weighs -8 lbs?

Correct.

WornSaddle said:

In other words, how much is it worth to have a 14lb bike rather than a 17lb bike when loosing 3 lbs is A LOT cheaper (namely free)?

The first may cost you a couple grand, the second only some (or a lot) of discipline.

WornSaddle said:

Well, after about 30 years off I'm riding again and shopping for an updated bike (to replace mid 70's Raleigh Pro's). When I was racing I weighed about 130, by mid 40's I was 210 and several years ago I went down to 155 and now range between 157 & 167. So the question:

Is saving 3lbs of static non-rotating weight on a bike the same as reducing my body weight by 3lbs?

In other words, how much is it worth to have a 14lb bike rather than a 17lb bike when loosing 3 lbs is A LOT cheaper (namely free)?

Energy to accelerate a bicycle is the mass of the bike and rider. To the extreme, same energy with a 200 pound bike and 20 pound rider as 20 pound bike and 200 pound rider.

The 'issue' is that you can lose a LOT more weight off the body than the bike, as you know. 'Worth' is a personal decision but 3 pounds is 3 pounds regardless of where it is.

Many studies have shown rotational weight differences on a bicycle, altho measurable, are teeny, tiny.

Weight is VASTLY overplayed in the bike biz these days. Mostly cuz there are only 2 things you can measure on a bicycle, weight and price. So...lighter and more expensive becomes 'better', even if they aren't.

fatandslow said:

So If I lose the 30 lbs I need to, and my bike weighs 22, It will be like my bike weighs -8 lbs?

That's right. I tell guys all the time that if I lose 19 pounds my bike weighs zero....

A couple of thoughts on why they may be different.

- They 'seem' to be different. Nothing like pure conjecture :-) When I lost 40 lbs over the winter I expected a huge difference in riding. There was a difference, but it wasn't huge. It 'seems' though that if I'd been riding with a 40lb weight in the middle of my frame that if I removed it there would be a much more noticeable difference.

- Why? The 40lb weight in my bike frame is weight being acted upon. When I press down on my peddle going up a hill with that weight I'm acting against that weight. However, 40lbs of weight in my body is on the side of the peddle doing the acting, not the side being acted upon.

WornSaddle said:

A couple of thoughts on why they may be different.

- They 'seem' to be different. Nothing like pure conjecture :-) When I lost 40 lbs over the winter I expected a huge difference in riding. There was a difference, but it wasn't huge. It 'seems' though that if I'd been riding with a 40lb weight in the middle of my frame that if I removed it there would be a much more noticeable difference.

- Why? The 40lb weight in my bike frame is weight being acted upon. When I press down on my peddle going up a hill with that weight I'm acting against that weight. However, 40lbs of weight in my body is on the side of the peddle doing the acting, not the side being acted upon.

Additional 40 pounds on you isn't helping you push the pedal down. When you pedal you are acting against the weight(gravity) regardless of where it is. Gravity is gravity. It doesn't matter if you are riding the bike or carrying it, you still have to lift it up the hill.

When I lost 10 pounds I felt a HUGE difference, subjective to say the least.

Peter@vecchios said:

Energy to accelerate a bicycle is the mass of the bike and rider. To the extreme, same energy with a 200 pound bike and 20 pound rider as 20 pound bike and 200 pound rider.

The 'issue' is that you can lose a LOT more weight off the body than the bike, as you know. 'Worth' is a personal decision but 3 pounds is 3 pounds regardless of where it is.

Many studies have shown rotational weight differences on a bicycle, altho measurable, are teeny, tiny.

Weight is VASTLY overplayed in the bike biz these days. Mostly cuz there are only 2 things you can measure on a bicycle, weight and price. So...lighter and more expensive becomes 'better', even if they aren't.

I absolutely agree. The emphasis on weight differences between bikes in grams is misplaced. Comfort and durability should be at least as important.

Just another axiom:

If you lose 3lbs off the bike weight you will be 3 lbs lighter anytime you are riding your bike.

But only when you are riding your bike.

If you lose 3 lbs off your self, you'll be 3 lbs lighter regardless of what you're doing: climbing stairs, chasing the dog, walking down the street, lying on top of the missus, etc.

[QUOTE=Bob Ross;3905869 If you lose 3 lbs off your self, you'll be 3 lbs lighter regardless of what you're doing:... lying on top of the missus, etc.[/QUOTE]

To hell with that...I'm resting my legs and letting her do all the work on top...

64Paramount said:

Then, buy that insanely expensive 14 pound bike and lose some body weight. You'll have the best of both worlds. 🙂

Yep. No reason at all to make this an either/or comparison when the factors are completely independent.

frenchyge said:

Yep. No reason at all to make this an either/or comparison when the factors are completely independent.

I see it pretty much as you. My only issue is when someone buys a light bike/component/thin condom thinking it actually makes a performance difference. When someone chooses to buy something lighter just because they like it or it flips their main bus on, that's great. Cycling is in part about passion, and we should feed that passion, whatever form it takes.

Now, I'm a tech geek, and I built my last bike (bike before my Look 595) as a weight weenie exercise, just to see how light I could make it, within my own imposed limits, and still be everyday rideable. That was fun, albeit expensive, but still fun, but it was still just an exercise, not a hunt for performance advantage.

This religiously imposed weight limit for cyclists--i.e. a cyclist should lose every microgram of fat on their bodies before buying a lighter bike than is approved by the experts--is really ridiculous and kind of pretentious.

I really don't get why so many cyclists are concerned with what someone else is riding, using, or wearing. As Confucius said, "There are 32 officially sanctioned ways to skin a cat."

Why is riding a bike more efficient than walking or running?

When riding a bike you are not carrying your weight, you are merely propelling yourself and the bike forward. The weight of the bike is a small burden because you are not carrying it.

When walking or running your legs are carrying your weight as well as doing the propelling.

I have no facts or figures to back up the above, but if it is true then losing body weight will have much more effect when walking or running compared to riding a bike.

Agree with your analogy for riding a bike on flat ground. However, as soon as the road tilts up, you are "carrying" your bodyweight up the hill, just like a runner does. Heavy cyclists can do fine on the flats against leaner riders, but when the climbing starts, physics takes over.

Akadat said:

....losing body weight will have much more effect when walking or running compared to riding a bike.

Right. So, is it safe to assume that competitive runners/walkers obsess about the weight of their shoes? 😄

So today I did an experiment. I hung a 45lb barbell weight in the middle of a bike frame (older Panasonic DX5000). Went for a ride with some moderate hills. Conclusion: Frame weight is HUGELY different than body weight. I seemed to have much greater difficulty going up several hills than when I weighed 40lbs more and was in worse shape. I usually average about 19.5mph on this loop, today was 14.9. When I was heavier and in worse shape around 16.

Maybe I should track my riding this loop numerous times with and without the weight and then put on 40lbs over the winter (shouldn't be too difficult :-) and then see how those hills are in the spring :-)