[hummina shadeeba]

wait..your graph has wind resistance as dominant past 12 km/h. I’ve seen it at 15mph. Also on that graph how would drivetrain losses not be paralleling rolling resistance losses and both should be linearly produced with rpm and parallel to each other, no?

 

[tlg]

I’m talking about suspension or impedance losses. If u bother to read what the links say and what I’m saying you’d find you’re actually agreeing with me in that the body converting possibly hundreds of watts in momentum to heat seems unrealistic. That’s what they say. That’s the definition of suspension or impedance losses

The thread is 80 posts long. If you're referring to a link, add it. No one is going to guess which one you're talking about.

That link is a specific test... riding on rumble strips. I'm not sure that translates to tire rolling resistance.
Where did those 290 Watts go? After testing various pieces of equipment on the rumble strips all day, I knew where the energy went: My body was sore all over. I had experienced suspension losses on my own body!
Why do you think his body was sore? He was doing work. It takes watts to do work.

But I do agree, not all '290' watts are being absorbed by the body. They are missing some things. There is going to be significant increases in rolling resistance and tire deformation (heat).

They could be trivially caused by micro-jumps due to road irregularities. In a jump, part of the energy is probably lost in the landing and not converted in forward motion.

This is more or less a correct explanation. Any forward motion transferred to vertical force lifting the bike/rider would have a reactionary force down into the ground ( causing heat). And the opposite when the bike/rider lowers 'land' on the ground.

I wish I had a FLIR. This would be pretty easy to confirm. Riding on rumble strips should make the tires warmer.

if a body riding a bike has no possible friction, such as a block of concrete,

This is not true. Solid objects have friction.

How Newton’s Cradles Work

Five metallic balls on slender threads sit side by side. As one on the end hits the rest, the one on the opposite end rises and falls. Why don't the balls in the middle move? It's complicated.

science.howstuffworks.com

Though a small amount of friction comes from air resistance, the main source is from within the balls themselves. So what you see in a Newton's cradle aren't really elastic collisions but rather inelastic collisions, in which the kinetic energy after the collision is less than the kinetic energy beforehand. This happens because the balls themselves are not perfectly elastic -- they can't escape the effect of friction. But due to the conservation of energy, the total amount of energy stays the same. As the balls are compressed and return to their original shape, the friction between the molecules inside the ball converts the kinetic energy into heat. The balls also vibrate, which dissipates energy into the air and creates the clicking sound that is the signature of the Newton's cradle.

 

[hummina shadeeba]

I don’t think the cradle is a relevant analogy. A block of concrete bolted to a bike frame is not moving in relation to the bike. There is no collision

 

[Lombard]

I am really disappointed you guys couldn't wait for me to make more popcorn.

 

[hummina shadeeba]

I am really disappointed you guys couldn't wait for me to make more popcorn.

U don’t have to be the popcorn guy again and you can be an engineer this time. Give it a shot.

 

[Lombard]

U don’t have to be the popcorn guy again and you can be an engineer this time. Give it a shot.

Nope. I'm the popcorn guy. I sell beer and peanuts too.

 

[Kerry Irons]

I’m talking about suspension or impedance losses. If u bother to read what the links say and what I’m saying you’d find you’re actually agreeing with me in that the body converting possibly hundreds of watts in momentum to heat seems unrealistic. That’s what they say. That’s the definition of suspension or impedance losses

Suspension Losses Confirmed – Rene Herse Cycles

www.renehersecycles.com

but there’s room for variables as written below (gotten from discussion at bottom of the link just above): Micro jumps.




“However, I am not sure that this suspension losses are caused by vibrations in the body tissues. They could be trivially caused by micro-jumps due to road irregularities. In a jump, part of the energy is probably lost in the landing and not converted in forward motion. Even Josh Poertner seems to suggest a similar explanation.
However, apart from my hypothetical explanations, to establish if the losses are due to body tissue vibrations or micro-jumps, would be hard to do. Probably one should use a trike (able to travel for short distances with no one on board) with ballast and on a slope, and see if the results are the same, that is lower pressure leading to faster speeds. If the results are confirmed also for an unammend trike, then the reason for suspension losses is not body tissue vibrations but micro jumps.”

(the solid ballast (concrete) vs water/fat/bone roll test I also proposed).

the energy of course has to go somewhere. Bike suspension forks heat up but is it the spring itself’s internal friction, which would be analogous to our body on the bike, or is it friction of the other fork parts.

Give up. You're embarrassing yourself. The vibrations transmitted to the body by lack of compliance of your tires is converted to heat. It's such an amazingly simple concept that apparently you are unable to comprehend it.

 

[hummina shadeeba]

It's such an amazingly simple concept that apparently you are unable to comprehend it.

You should tell all these guys to stop doing research and they’re embarrassing themselves and it just turns to heat:

PART 4B: ROLLING RESISTANCE AND IMPEDANCE

The concept of Impedance is a relatively new and uncharted territory for cycling blogs, yet is something that each of us have a feel for.

blog.silca.cc

Tell everyone to stop all research related to energy transfer and it just turns to heat duh. It’s all so simple they just haven’t figured it out like you have.

Who is embarrassed? Just me or tig too?
Tig:

There are not "hundreds of watts" of energy taken from a bicycle’s momentum and turned to heat. That's ridiculous

the question is WHERE is it turning to heat. But best you not think about it. Wait for some authority to tell you. Is there one?

the great part is the answers can likely be figured through simple experiments as they’re doing and the resulting info could greatly alter bicycle design. Do u really want that fancy stiff bike or are seemingly outdated old steel bikes more efficient? Maybe Fignon wouldve beaten LEMOND with a softer saddle and more bar tape? For sure his over-pumped skinny tires didn’t help. Maybe he would’ve just said it turns to heat and he’s comfy in second place.

 

[Kerry Irons]

You should tell all these guys to stop doing research and they’re embarrassing themselves and it just turns to heat:

PART 4B: ROLLING RESISTANCE AND IMPEDANCE

The concept of Impedance is a relatively new and uncharted territory for cycling blogs, yet is something that each of us have a feel for.

blog.silca.cc

Tell everyone to stop all research related to energy transfer and it just turns to heat duh. It’s all so simple they just haven’t figured it out like you have.

Who is embarrassed? Just me or tig too?

the question is WHERE is it turning to heat. But best you not think about it. Wait for some authority to tell you. Is there one?

the great part is the answers can likely be figured through simple experiments as they’re doing and the resulting info could greatly alter bicycle design. Do u really want that fancy stiff bike or are seemingly outdated old steel bikes more efficient? Maybe Fignon wouldve beaten LEMOND with a softer saddle and more bar tape? For sure his over-pumped skinny tires didn’t help. Maybe he would’ve just said it turns to heat and he’s comfy in second place.

You repeatedly question whether the shaking of human tissue can generate heat. Is this just a troll or do you really not believe this is how energy from road vibrations is dissipated? If you really don't believe it, then you either think it is dissipated in some other form or you don't believe the vibrational energy is dissipated. Please explain which of these you believe. Or are you just trolling.

 

[hummina shadeeba]

I question that 100s of watts of momentum would be lost to heat from friction between the organs of a body when riding a rough surface. If you have evidence that hundreds of watts of what would be momentum are lost to friction between organs of the body post it.



here we have maybe 8 watts lost to the contact between bike and body (ass and hands) on a cobblestone road at I believe 26 km/h:
Using Power as a Metric to Quantify Vibration Transmitted to the Cyclist (sciencedirectassets.com)

"The mean absorbed power corresponds to the rate of energy dissipated as heat by the vibration of the human body parts in contact with the bike." seems to suggest the friction is between bike and rider as apposed to inside the body.

 

[asgelle]

I question that 100s of watts of momentum ...

What on earth is a watt of momentum?

 

[hummina shadeeba]

What on earth is a watt of momentum?

i shouldve written energy or joules. watts are joules per second.

 

[asgelle]

i shouldve written energy or joules. watts are joules per second.

If that's what you meant, then what on earth is a Joule of momentum? The units for energy (Joule) are kg m^2/s^2 for momentum it's kg m/s. Do you understand how momentum, force, energy, and power are related?

 

[hummina shadeeba]

i dont know any related math or terminology but feel safe in saying there is potential energy in a moving body/bike and that energy is lost somewhere due to rolling resistance or impedance. whatever term you want to use or is appropriate to use to define the potential energy stored in a moving body use that one and plug it in. if you want to explain how it should be defined go ahead.

Difference Between Momentum and Energy | Compare the Difference Between Similar Terms

Momentum vs Energy Momentum and energy (kinetic energy) are important properties of a moving object and governed by Newton’s Laws of motion. They are both

www.differencebetween.com

 

[asgelle]

i dont know any related math

This is correct.

... but feel safe in saying there is potential energy stored in a moving body/bike.

This is not.
Perhaps you should write less and read more.

 

[hummina shadeeba]

there's energy in a moving bicycle. as i said i dont know the terminology. got a problem with saying there's"energy" in a moving bike? i guess should be dubbed kinetic.

but thanks for your correction. seems im reading and writing.

 

[hummina shadeeba]

This is correct.

This is not.
Perhaps you should write less and read more.

i take it back and still believe there is potential energy in a bicycle. potential energy is there as the bicycle is deflected by micro bumps. the kinetic energy of the moving bike is partially turned to potential. kinetic energy, or maybe can be formally dubbed momentum, is redirected upward against gravity when a bump is hit where it becomes potential energy.

 

[asgelle]

i take it back and still believe there is potential energy in a bicycle. potential energy is there as the bicycle goes up and over micro bumps. the kinetic energy of the moving bike is partially turned to potential. You have a problem with that?

I have no problem, it's wrong, but that doesn't pose a problem for me. Perhaps it's time to review the rule of holes.

 

[hummina shadeeba]

I have no problem, it's wrong, but that doesn't pose a problem for me. Perhaps it's time to review the rule of holes.

care to explain how a moving bicycle isnt turning its kinetic energy to potential as it hits micro bumps. if we go further and say..biggg bumps we have what we could term a jump and then its obvious there is kinetic turned to potential. go ahead. dont just say it show it. i think youre wrong and im right.

doesnt bother me talking about stuff im not familiar with. that's how you learn sometimes.

 

[asgelle]

doesnt bother me talking about stuff im not familiar with. that's how you learn sometimes.

It's been my experience that I learn very little when I'm talking (writing).

If you'd like tutoring in high school physics, my rate is $100/hr.