Steel frames and le Tour

In article ,
wrote:

On Fri, 18 Jul 2008 23:30:32 -0700, Howard Kveck
wrote:

In article ,

wrote:

The rest of the "heavier" feeling was probably due to all the extra
attention that I paid (does it feel heavier? lighter? how does it
normally feel?), plus the unavoidable knowledge that there were
_seven_ whole pounds sitting right there in plain sight whenever I
looked down at the speedometer.

One point I haven't seen made, Carl: this isn't exactly a blind test, is
it? If
you really wanted to seriously test this, I think you'd have to devise a way
to do it
so you were unaware of when the bike had the extra weight on it when you
went out on
the road.

Dear Howard,

Here's the relevant post:

No, Carl, you state in your above post "the unavoidable knowledge that there were
_seven_ whole pounds sitting right there in plain sight." That pretty much defines it
as *not* a blind test.

--
tanx,
Howard

The bloody pubs are bloody dull
The bloody clubs are bloody full
Of bloody girls and bloody guys
With bloody murder in their eyes

remove YOUR SHOES to reply, ok?

On Fri, 18 Jul 2008 23:12:18 -0600, Bret Wade
wrote:

I've been using CF levers on my cross bikes for years and
crashed many times with no damage.

O M G

On Sat, 19 Jul 2008 01:04:33 -0700, Howard Kveck
wrote:

In article ,
wrote:

On Fri, 18 Jul 2008 23:30:32 -0700, Howard Kveck
wrote:

In article ,

wrote:

The rest of the "heavier" feeling was probably due to all the extra
attention that I paid (does it feel heavier? lighter? how does it
normally feel?), plus the unavoidable knowledge that there were
_seven_ whole pounds sitting right there in plain sight whenever I
looked down at the speedometer.

One point I haven't seen made, Carl: this isn't exactly a blind test, is
it? If
you really wanted to seriously test this, I think you'd have to devise a way
to do it
so you were unaware of when the bike had the extra weight on it when you
went out on
the road.

Dear Howard,

Here's the relevant post:

No, Carl, you state in your above post "the unavoidable knowledge that there were
_seven_ whole pounds sitting right there in plain sight." That pretty much defines it
as *not* a blind test.

Hahaha.

Paul M. Hobson wrote:
John Forrest Tomlinson wrote:
On Mon, 14 Jul 2008 00:37:34 -0700 (PDT), hizark21
wrote:

But
this illustrate how easily composite frames are damaged.

But they're not. You just don't get it.

Here's another example: a friend of mine was riding around warming up
at a race. He did a few sprints and something didn't feel right. He
looked carefully at the bike and saw the downtube was cracked.

Does that prove anything? The bike may/probably was damaged in an
earlier crash. So what?

Oh, byt the way, this was 1983 and the frame was Columbus SL.

Just so you know John, this anecdote only supports the CFRP naysayers
who prefer steel because it's failure is slow and noticeable -- not
catastrophic.

\\paul


er, steel's failure is catastrophic. and not always slow, certainly not
in a crash. fatigue failure is typically slow crack nucleation,
increasingly rapid crack growth, then catastrophic fracture.

carbon's failure in crash mode is catastrophic, so no real difference
there [except for the carbon being stronger of course]. carbon's
failure in fatigue, if you can wait around that long, is slow
disintegration accompanied by much audible cracking, creaking, and
otherwise voluble telltales. if you're standing on a plank of wood, and
it starts to creak and groan, it's rare that you wouldn't have time to
move off safely. for some reason though, when it comes to carbon, the
fredly world of r.b.t seems unable to understand and apply these same
principles to carbon bike components, and thus they desire to ignore
those warning signs, and indulge their desire for presumptive
scare-mongering. perverse.

On Sat, 19 Jul 2008 01:04:33 -0700, Howard Kveck
wrote:

In article ,
wrote:

On Fri, 18 Jul 2008 23:30:32 -0700, Howard Kveck
wrote:

In article ,

wrote:

The rest of the "heavier" feeling was probably due to all the extra
attention that I paid (does it feel heavier? lighter? how does it
normally feel?), plus the unavoidable knowledge that there were
_seven_ whole pounds sitting right there in plain sight whenever I
looked down at the speedometer.

One point I haven't seen made, Carl: this isn't exactly a blind test, is
it? If
you really wanted to seriously test this, I think you'd have to devise a way
to do it
so you were unaware of when the bike had the extra weight on it when you
went out on
the road.

Dear Howard,

Here's the relevant post:

No, Carl, you state in your above post "the unavoidable knowledge that there were
_seven_ whole pounds sitting right there in plain sight." That pretty much defines it
as *not* a blind test.

Dear Howard,

Er, where did I argue with you?

The relevant post that I quoted in full makes it plain as sin that it
wasn't a blind test.

It even invites comment on the flaws and likens it to the original
article that provoked that whole thread:

"Explaining predictions may be as much fun as pointing out flaws in
the test or comparing it to the original article about the 'noticeably
robust forward thrust' noticed when the reporter rode a 14-lb bike for
a day instead of his usual 21-lb behemoth."

For fun, tell us how you would "seriously test" for the speed and
acceleration effects of a 7-lb bicycle weight increase and what
blinding procedures you'd use.

Of course, there's not much need for any blind testing of the effect
of a bicycle weight increase on acceleration and terminal velocity.

After all, Newton gave us enough hints for clever people interested in
physics to construct calculators like these:
http://bikecalculator.com/veloUS.html
http://www.analyticcycling.com/
http://www.recumbents.com/wisil/simul/HPV_Simul.asp

Cheers,

Carl Fogel

On Jul 18, 8:24*pm, wrote:
On Fri, 18 Jul 2008 14:40:56 -0700 (PDT), "



wrote:
On Jul 17, 4:10 pm, "Tom Kunich" cyclintom@yahoo. com wrote:
"Tuschinski" wrote in message

....

*And indeed when you look at the actual numbers of
failures you find that a correctly built steel frame, even superlight
ones,
very seldom fail and when they do it is pretty plainly a workmanship or
material error.

Oh come on Tom, that's blatantly false. Back in the days, when we all
raced Reynolds/Columbus we broke frames. Some of it by crashing, some
by bad handling, some by bad manufacturers.

And yes, we also broke Alu frames. And now we break CF frames
*shrug*.

Such is life ^^

I don't follow you here. Well built steel frames seldom fail. Well built AL
frames (the super light ones) fail whether you take good care of them or
not. I have personally observed quite a few carbon fiber failures and these
bikes are EXPENSIVE.

And the total savings a My Time VX costs almost 4 times more than my
Basso Loto and they ride almost identically and weigh within a lb of each
other.

I used to have a Basso Ascot. It was my favorite bike ever. It died in
a collision with a car and I didn't do too well either. It was a great
frame, though. I think that it was the geometry that made the bike
feel really nice. I don't know if your Lotto has the same geometry as
my Ascot, but if it does, I know why you like it. I am sure that I
will also be able to get a great ride with frames of different
materials that have the same geometry as my Ascot. A lot of the times,
a cyclist may like a bike more because the geometry makes it feel
faster.

I believe , like Carl, that the feeling is just that and your speed
does not necessarily increase or decrease that much. However, it is
great to ride on a bike that has "that" feeling.

Andres

Dear Andres,

The day after I removed the 7 pounds of weights from my bike, I went
for my usual afternoon ride.

I didn't notice any surge in speed or acceleration when I lost the 7
pounds.

In fact, I didn't even have a twinge of boy-I'd-like-a-lighter-bike!

I suspect that a whole new bike might have felt (and looked) different
enough in various ways (tires, wheels, geometry, saddle, brakes, and
so on) to make me easy prey for a salesman.

But just strapping the extra weight onto the same old bike without
changing anything else left me with nothing more than the very suspect
feeling that the bike felt "heavier".

Much of that "heavier" feeling was probably just the vibration damping
of the extra rubber-encased 7 pounds on the top tube. (After all, it
amounted to only a 3.2% weight increase.)

The rest of the "heavier" feeling was probably due to all the extra
attention that I paid (does it feel heavier? lighter? how does it
normally feel?), plus the unavoidable knowledge that there were
_seven_ whole pounds sitting right there in plain sight whenever I
looked down at the speedometer.

Some posters might want to try the experiment of just adding a few
extra pounds to their familiar bike and comparing whatever difference
they "feel" to whatever happens to their actual times around a
familiar route.

Cheers,

Carl Fogel

I have a ti road bike that weighs probably about 20 pounds without
anything and a TT Al bike that weighs about the same. I usually ride
anywhere three to five hours each day on weekends but no much during
the weeks. I teach a couple of spinning classes to stay in moderate
biking shape and I also run and swim. But, once in a while I do some
riding around my neighborhood. On weekends I carry three 24 ounce
water bottles, a toolbag with tubes, tools, keys, etc. (old tubie bike
filled with junk) a bento box with wallet, cellphone and granola bars.
When I pick up my bike it feels like an anchor. However, on it, I
really cannot tell the difference between my unloaded bike for the
occasional weekday ride and the loaded bike for the weekend adventure.
I haven't tried to make a conscious effort to feel the difference, but
apparently, it feels the same.

Both bikes have similar geometry (76 degree angles) and I have similar
position on both bikes. I only get narrower on the TT bike. The only
noticeable advantage is the aerobars on the TT bike. The aerobars
probably give me an extra mile of speed. I don't get that much lower
on my TT bike than on my road bike. I am probably just as low with on
the drops and on the aerobars. However, bringing my elbows together I
can feel less wind going into my chest, face. etc. When I am out of
shape and need to keep up with speed demons, I bring the TT bike and
hang on at the back.

Andres

wrote:
On Fri, 18 Jul 2008 22:33:36 -0600, Bret Wade
wrote:

wrote:
On Sat, 19 Jul 2008 00:57:07 +0200, Lou Holtman
wrote:

wrote:
On Thu, 17 Jul 2008 23:08:40 -0600, Bret Wade
wrote:

wrote:
On Thu, 17 Jul 2008 14:13:43 -0600, Bret Wade
wrote:

wrote:

The original question was whether a rider can _feel_ such tiny
changes--that same old laughable "noticeably robust forward thrust."
I wouldn't put it in those words but I have felt that sensation when
switching from a 4 lb Ti frame to a 2.5 lb Al frame. It felt faster from
the first pedal stroke. It was a team bike that I was somewhat skeptical
of riding, so it wasn't just wishful thinking. Others on the team had
similar experiences. I understand physics well enough to know that the
sensation was misleading.

Bret
Dear Bret,

Forgive a long-winded answer, but you're so refreshingly reasonable
that I want to avoid any offense.

What interests me is the idea that a 1.5 lb lighter frame "felt faster
from the first pedal stroke"--possibly a generalization or even
hyperbole, but it's what we have to work with.

I don't know the actual weights, but it was a whole team, so a 150
pound rider and a 16.5 pound bike would probably be in the ballpark.

That theoretical 166.5 pound bike and rider would drop to 165 pounds,
about 0.9%.

The bike itself would have dropped from 16.5 to 15.0 pounds, about
10%.

The bike might twitch from side to side or heave forward 10% easier.

But I gather that we agree that the speed and acceleration
improvements are going to be so small that a calculator is necessary
to see them.

In fact, they don't show up on my first effort:
http://bikecalculator.com/veloUS.html

I tried 400 watts, a 150 pound rider, 15 and 16.5 pound bikes,
tubulars, and drops.

Because the calculator has only 2-decimal precision, both bikes went
the same speed--27.85 mph.

(A quick look at the time for 20 miles reassured me that the
calculator is still grinding out infinitesimal details--43.08 minutes
versus 43.09 minutes, a 0.01 minute lead, 0.6 seconds.)

Let's send the bikes up the Alp d'Huez, which I have handy at 8.1% and
13.8 km (8.56 miles):
http://en.wikipedia.org/wiki/Alpe_d'Huez

The steep grade teases out a speed difference, but it's still nothing
that a rider could detect.

I get 41.03 minutes versus 41.33, a 0.3 minute or 18 second lead after
almost 2500 seconds. That's ~1% faster.

The speeds are 12.52 mph versus 12.43 mph.

Raise the power to 500 watts, and the time and difference shrink to
34.04 versus 34.27, a little under 14 seconds, at 15.09 versus 14.99
mph.

In other words, it takes the Alp d'Huez and a light, world-class rider
to produce a tenth of a mile per hour and 14-second difference with a
1.5 pound lighter bike.

So I'm glad that you understand the physics well enough to know that
the impression was probably misleading. In unblinded testing, it's
hard to tell which way our misperceptions will go. Just paying
attention (because we're testing) distorts what we think we feel. Evil
psychologists love to demonstrate how students will mis-measure the
same lumber with the same measuring tapes, according to whether
they've been told that it's important for the boards not to be too
long, for them not to be too short, or that the measurement accuracy
does (or doesn't) really matter.

Cheers,

Carl Fogel
Dear Carl,

No need to apologize, I understand that bad habits can be hard to break.
The hardest thing I've done in my life is break a pack a day Marlboro habit.

Anyway, I'll just point out that your very detailed analysis involves
steady state aerobic climbing whereas most "Wow, this bike is fast!"
moments will come during anaerobic accelerations. Not that I think the
result would be much different. A small change in total mass won't
affect either situation much.

The bike weighed 16 lbs, rider was 165 lbs and max power was 1350 watts.

Cheers,
Bret
Dear Bret,

It doesn't much matter whether we talk about a momentary acceleration
or steady-state cruising.

Heck, it doesn't much matter whether we're talking about a grandmother
setting off to the grocery store or a pro suddenly giving everything
he's got up the Alp d'Huez.

The mistaken belief that Newton's world changes dramatically for
really powerful riders or really steep hills keeps coming up in this
thread, so forgive me for ploughing through the same old stuff again.

***

160 + 16.0 = 176.0 lbs = 72.727 kg + 7.273 kg = 80.000 kg
160 + 17.5 = 177.5 lbs = 72.727 kg + 7.955 kg = 80.682 kg

177.5/176.0 = ~1.008, so acceleration should increase 1% in the real
world.

Sprint acceleration calculator:
http://www.analyticcycling.com/DiffE...n500_Page.html

First, let's see how much faster the 1.5-lb-lighter bike accelerates
from a standing start at 1350 watts up a convenient 8.1% stretch of
the Alp d'Huez.

Use max power 1350, avg power 1349.9, slope 0.081, and do it for a
distance of 10 meters (the very last field).

Then do it again for a max power of 100 watts and an average of 99.9.

1350 watts 100 watts
176.0 177.5 176.0 177.5
meters time time time time
1.0 0.3 0.3 1.1 1.1
2.5 0.6 0.6 2.4 2.4
5 1.2 1.2 4.2 4.2
10 2.1 2.1 7.6 7.6
15 2.8 2.8 10.9 11.0
20 3.3 3.3 14.3-14.4
25 3.9 3.9 17.6-17.8
50 6.4 6.4 34.4 34.7
100 10.6 10.7* 68.0 68.6
150 14.6 14.6 101.7 102.5
200 18.4 18.4 135.4 136.5
250 22.0-22.1 169.2 170.6
300 25.7-25.8 203.1 204.8

* shows how rounding can affect things

In other words, a 1.5-lb acceleration difference takes a long time up
an 8.1% grade to show up on a calculator that reads in tenths of a
second.

It takes 250 meters for a ~0.5% time difference to show up reliably on
a 0.1 second stopwatch for the powerful rider.

Neither rider is going to notice an off-the-line ~1% acceleration
increase with the seat of his pants.

If he's extrapolating from the change in how he can heave the 10%
lighter bike around, then he must have an impressive calculator inside
his head.

***

For steady-state cruising up the same hill, the speed differences are
even less than the acceleration differences.

Use 1350 watts, 8.1% grade, rider 160, bikes 16 and 17.6 lbs,
tubulars, hoods he
http://bikecalculator.com/veloUS.html

I get 27.99 mph versus 27.90 mph, 99.678% as fast. Once you accelerate
to cruising speed, the high speed wind drag effect reduces the ~1%
idealized mass difference to ~0.3%.

Now try grandma at 100 watts up the same 8.1% grade.

She goes 3.15 versus 3.17 mph.

***

As has been suggested, something besides the 1.5 lb frame difference
might account for the faster-from-the-first-pedal impression.

All of the technical possibilities (stiffer frame, different tires,
better aero, and so on) are dwarfed by the stubborn psychological
effect of trying a new bike.

Even the same thing with a different paint scheme will feel
"different" if we're told "go ahead and try this new [fill in the
blank]."

Trying something with an eye toward comparing it puts us in an
entirely different position than just using something familiar.

Cheers,

Carl Fogel
You can stop now Carl. You take away peoples illusions and beliefs with
your straightforward calculation. I someway this ****es them off. You
are arguing now with people who don't want to belief. No point in that.
'...... anaerobic accelerations.....' Geezes what crap is that?

Lou
Dear Lou,

Well, it's the kind of thing that I'd have come up with myself before
I looked into things.

Bret seems quite reasonable to me. He felt _something_ different, and
so did his whole team, so if it doesn't make sense with 350 watt
examples, maybe it was because of the 1350 watt sprint?
You're being slightly disingenuous.I never questioned your results. I
just pointed out that your analysis was framed improperly wrt to the claims.

Bret

Dear Bret,

Sorry. I didn't mean to give you that impression.

Possibly I've misunderstood you.

Which claims by whom?

Cheers,

Carl Fogel

The phrase "noticeably robust forward thrust" to me implies
acceleration. All of your initial analysis involved steady state
climbing. I was just pointing out that your analysis isn't framing the
problem correctly. Maybe I missed a subject change. I can't say I read
the entire thread.

I did explicitly state that I didn't expect a different outcome:

Not that I think the result would be much different. A small change
in total mass won't affect either situation much.

Bret

John Forrest Tomlinson wrote:
On Fri, 18 Jul 2008 23:12:18 -0600, Bret Wade
wrote:

I've been using CF levers on my cross bikes for years and
crashed many times with no damage.

O M G

Bike weight is important on in a cross race what with all the lifting,
especially for those of us with bad backs.

"Bret Wade" wrote in message
m...
John Forrest Tomlinson wrote:
On Fri, 18 Jul 2008 23:12:18 -0600, Bret Wade
wrote:

I've been using CF levers on my cross bikes for years and crashed many
times with no damage.

O M G

Bike weight is important on in a cross race what with all the lifting,
especially for those of us with bad backs.

And if there's one sure way to save weight it's carbon levers.

On Sat, 19 Jul 2008 18:09:07 -0600, Bret Wade
wrote:

wrote:
On Fri, 18 Jul 2008 22:33:36 -0600, Bret Wade
wrote:

wrote:
On Sat, 19 Jul 2008 00:57:07 +0200, Lou Holtman
wrote:

wrote:
On Thu, 17 Jul 2008 23:08:40 -0600, Bret Wade
wrote:

wrote:
On Thu, 17 Jul 2008 14:13:43 -0600, Bret Wade
wrote:

wrote:

The original question was whether a rider can _feel_ such tiny
changes--that same old laughable "noticeably robust forward thrust."
I wouldn't put it in those words but I have felt that sensation when
switching from a 4 lb Ti frame to a 2.5 lb Al frame. It felt faster from
the first pedal stroke. It was a team bike that I was somewhat skeptical
of riding, so it wasn't just wishful thinking. Others on the team had
similar experiences. I understand physics well enough to know that the
sensation was misleading.

Bret
Dear Bret,

Forgive a long-winded answer, but you're so refreshingly reasonable
that I want to avoid any offense.

What interests me is the idea that a 1.5 lb lighter frame "felt faster
from the first pedal stroke"--possibly a generalization or even
hyperbole, but it's what we have to work with.

I don't know the actual weights, but it was a whole team, so a 150
pound rider and a 16.5 pound bike would probably be in the ballpark.

That theoretical 166.5 pound bike and rider would drop to 165 pounds,
about 0.9%.

The bike itself would have dropped from 16.5 to 15.0 pounds, about
10%.

The bike might twitch from side to side or heave forward 10% easier.

But I gather that we agree that the speed and acceleration
improvements are going to be so small that a calculator is necessary
to see them.

In fact, they don't show up on my first effort:
http://bikecalculator.com/veloUS.html

I tried 400 watts, a 150 pound rider, 15 and 16.5 pound bikes,
tubulars, and drops.

Because the calculator has only 2-decimal precision, both bikes went
the same speed--27.85 mph.

(A quick look at the time for 20 miles reassured me that the
calculator is still grinding out infinitesimal details--43.08 minutes
versus 43.09 minutes, a 0.01 minute lead, 0.6 seconds.)

Let's send the bikes up the Alp d'Huez, which I have handy at 8.1% and
13.8 km (8.56 miles):
http://en.wikipedia.org/wiki/Alpe_d'Huez

The steep grade teases out a speed difference, but it's still nothing
that a rider could detect.

I get 41.03 minutes versus 41.33, a 0.3 minute or 18 second lead after
almost 2500 seconds. That's ~1% faster.

The speeds are 12.52 mph versus 12.43 mph.

Raise the power to 500 watts, and the time and difference shrink to
34.04 versus 34.27, a little under 14 seconds, at 15.09 versus 14.99
mph.

In other words, it takes the Alp d'Huez and a light, world-class rider
to produce a tenth of a mile per hour and 14-second difference with a
1.5 pound lighter bike.

So I'm glad that you understand the physics well enough to know that
the impression was probably misleading. In unblinded testing, it's
hard to tell which way our misperceptions will go. Just paying
attention (because we're testing) distorts what we think we feel. Evil
psychologists love to demonstrate how students will mis-measure the
same lumber with the same measuring tapes, according to whether
they've been told that it's important for the boards not to be too
long, for them not to be too short, or that the measurement accuracy
does (or doesn't) really matter.

Cheers,

Carl Fogel
Dear Carl,

No need to apologize, I understand that bad habits can be hard to break.
The hardest thing I've done in my life is break a pack a day Marlboro habit.

Anyway, I'll just point out that your very detailed analysis involves
steady state aerobic climbing whereas most "Wow, this bike is fast!"
moments will come during anaerobic accelerations. Not that I think the
result would be much different. A small change in total mass won't
affect either situation much.

The bike weighed 16 lbs, rider was 165 lbs and max power was 1350 watts.

Cheers,
Bret
Dear Bret,

It doesn't much matter whether we talk about a momentary acceleration
or steady-state cruising.

Heck, it doesn't much matter whether we're talking about a grandmother
setting off to the grocery store or a pro suddenly giving everything
he's got up the Alp d'Huez.

The mistaken belief that Newton's world changes dramatically for
really powerful riders or really steep hills keeps coming up in this
thread, so forgive me for ploughing through the same old stuff again.

***

160 + 16.0 = 176.0 lbs = 72.727 kg + 7.273 kg = 80.000 kg
160 + 17.5 = 177.5 lbs = 72.727 kg + 7.955 kg = 80.682 kg

177.5/176.0 = ~1.008, so acceleration should increase 1% in the real
world.

Sprint acceleration calculator:
http://www.analyticcycling.com/DiffE...n500_Page.html

First, let's see how much faster the 1.5-lb-lighter bike accelerates
from a standing start at 1350 watts up a convenient 8.1% stretch of
the Alp d'Huez.

Use max power 1350, avg power 1349.9, slope 0.081, and do it for a
distance of 10 meters (the very last field).

Then do it again for a max power of 100 watts and an average of 99.9.

1350 watts 100 watts
176.0 177.5 176.0 177.5
meters time time time time
1.0 0.3 0.3 1.1 1.1
2.5 0.6 0.6 2.4 2.4
5 1.2 1.2 4.2 4.2
10 2.1 2.1 7.6 7.6
15 2.8 2.8 10.9 11.0
20 3.3 3.3 14.3-14.4
25 3.9 3.9 17.6-17.8
50 6.4 6.4 34.4 34.7
100 10.6 10.7* 68.0 68.6
150 14.6 14.6 101.7 102.5
200 18.4 18.4 135.4 136.5
250 22.0-22.1 169.2 170.6
300 25.7-25.8 203.1 204.8

* shows how rounding can affect things

In other words, a 1.5-lb acceleration difference takes a long time up
an 8.1% grade to show up on a calculator that reads in tenths of a
second.

It takes 250 meters for a ~0.5% time difference to show up reliably on
a 0.1 second stopwatch for the powerful rider.

Neither rider is going to notice an off-the-line ~1% acceleration
increase with the seat of his pants.

If he's extrapolating from the change in how he can heave the 10%
lighter bike around, then he must have an impressive calculator inside
his head.

***

For steady-state cruising up the same hill, the speed differences are
even less than the acceleration differences.

Use 1350 watts, 8.1% grade, rider 160, bikes 16 and 17.6 lbs,
tubulars, hoods he
http://bikecalculator.com/veloUS.html

I get 27.99 mph versus 27.90 mph, 99.678% as fast. Once you accelerate
to cruising speed, the high speed wind drag effect reduces the ~1%
idealized mass difference to ~0.3%.

Now try grandma at 100 watts up the same 8.1% grade.

She goes 3.15 versus 3.17 mph.

***

As has been suggested, something besides the 1.5 lb frame difference
might account for the faster-from-the-first-pedal impression.

All of the technical possibilities (stiffer frame, different tires,
better aero, and so on) are dwarfed by the stubborn psychological
effect of trying a new bike.

Even the same thing with a different paint scheme will feel
"different" if we're told "go ahead and try this new [fill in the
blank]."

Trying something with an eye toward comparing it puts us in an
entirely different position than just using something familiar.

Cheers,

Carl Fogel
You can stop now Carl. You take away peoples illusions and beliefs with
your straightforward calculation. I someway this ****es them off. You
are arguing now with people who don't want to belief. No point in that.
'...... anaerobic accelerations.....' Geezes what crap is that?

Lou
Dear Lou,

Well, it's the kind of thing that I'd have come up with myself before
I looked into things.

Bret seems quite reasonable to me. He felt _something_ different, and
so did his whole team, so if it doesn't make sense with 350 watt
examples, maybe it was because of the 1350 watt sprint?
You're being slightly disingenuous.I never questioned your results. I
just pointed out that your analysis was framed improperly wrt to the claims.

Bret

Dear Bret,

Sorry. I didn't mean to give you that impression.

Possibly I've misunderstood you.

Which claims by whom?

Cheers,

Carl Fogel

The phrase "noticeably robust forward thrust" to me implies
acceleration. All of your initial analysis involved steady state
climbing. I was just pointing out that your analysis isn't framing the
problem correctly. Maybe I missed a subject change. I can't say I read
the entire thread.

I did explicitly state that I didn't expect a different outcome:

Not that I think the result would be much different. A small change
in total mass won't affect either situation much.

Bret

Dear Bret,

It's easy to miss things in hundreds of posts in various threads.

For a no-wind, no-tire-drag situation, F = M * A, so F/M = A.

It works uphill, downhill, or level.

A 14-lb bike is 7 lbs lighter than a 21-lb bike. With a 161-lb rider,
the total masses are 175 lbs versus 182 lbs. (Yes, we're confusing
weight and mass, but it's okay here.)

If we add 7 lbs, the mass rises by 182/175 (26/25 or 104.0%).

So the acceleration drops by 175/182 (25/26 or 96.154%).

Imagine a rider powerful enough to accelerate the light bike from zero
to 10 meters per second in one second. (Or yards or feet or inches or
minutes or hours or whatever units we choose.)

The same rider accelerates the heavier bike (and himself) to only
~9.615 meters per second in the same second.

(No one can do 10 m/s^2 on the level, but it makes the arithmetic very
simple.)

The light bike travels 5 meters (197 inches, a bit over 16 feet).

The heavy bike travels ~4.807 meters (almost 8 inches less).

Again, it doesn't matter whether the acceleration is uphill, downhill,
or on the level.

It doesn't matter whether we think the bike is squirting forward from
underneath (we just pull it back a moment later--the center of mass
doesn't accelerate differently).

It doesn't matter if we _really_ stomp on the pedal or vary the
acceleration or use plausibly lower or higher gears.

With the same power, a 26/25 change in mass produces a 25/26 change in
acceleration.

If we add wind drag and tire drag, that tiny change just gets smaller.

Cheers,

Carl Fogel