Fat tire riders look like "fat heads."

On 7/6/2020 10:41 AM, Lou Holtman wrote:
On Monday, July 6, 2020 at 7:15:32 PM UTC+2, Mark J. wrote:



It's a topic for another post, but I find on the road that energy /per
mile/ is surprisingly consistent, ranging from around 27 kJ/mile for a
gentle pootle to maybe 35 kJ/mile for a very brisk hilly ride, with most
rides in the 30-33 range. Not, of course, on rides that start and end
at different elevations.


Tell that to the people that say that 10-20 Watt on average is insignificant.

Lou

Not sure I understand your meaning, or how it's related to kJ/mile.
kJ/mile is energy expended per distance traveled. Watts are J/sec,
energy expended per unit of time. The two are nearly independent of
each other. I would agree that an extra 20W makes a very noticeable
difference, if that's what you meant, but I don't see the relationship
to kJ/mile.

In practice, on even vaguely similar courses, for me at least, higher
wattage translates to enough higher speed that the energy/distance
doesn't change that much. This is counterintuitive because it's well
documented that for a given bike/rider on a flat course, power
expenditure is roughly proportional to the cube of speed. Power would
have to go up linearly with speed for kJ/mi to be completely constant.

I suspect what's happening is that my average cycling speed (on pavement
w/o net climbing) doesn't vary much from one ride to the next, at least
not in the grand scheme of things. Subjectively, an 18mph avg ride
seems a lot brisker than a 15mph avg ride, but that's only a 20%
difference. So I'm staying in a very narrow range on that cubic
power/speed curve.

Mark J.

On 7/6/2020 11:14 AM, Sir Ridesalot wrote:
On Monday, 6 July 2020 13:15:32 UTC-4, Mark J. wrote:
On 7/5/2020 3:41 PM, Duane wrote:
Andre Jute wrote:
On Sunday, July 5, 2020 at 5:46:09 PM UTC+1, Jeff Liebermann wrote:
On Sat, 04 Jul 2020 19:21:20 -0700, Jeff Liebermann
wrote:

When you take the same rider and bike, and switch from slicks to
knobbies, you reduce the ground patch area. That increases the ground
pressure, which causes the rolling resistance to increase. That's one
reason why riding knobbies on pavement is like dragging an anchor.

I forgot to mumble something about tire pressu

"Everything You Think You Know About Bicycle Tire Pressure is Probably
Wrong"
https://www.roadbikerider.com/the-tire-pressure-revolution-by-jan-heine-d1/
Quoting:
Tire pressure has almost no effect on a tire’s speed.

If lower pressures don’t make tires slower, then you
can create wide tires with supple casings. You run
them at lower pressures, and you don’t give up any
performance on smooth roads. On rough roads, you
actually gain speed, because the tire (and you) bounce
less. And on all roads, you are more comfortable.

Conclusion
Tire pressure does not significantly affect your
bike’s rolling resistance, but the casing construction
of your tires does. This means that you can ride lower
pressures without going slower, and that wide tires
are no slower than narrow ones - as long as they have
similar casings. The fastest tires have supple casings
that consume less energy when they flex, and transmit
fewer vibrations, creating a win-win situation. These
tires roll super-fast no matter at what pressure you
run them.

So, you have a choice. A hard stiff narrow tire at high pressure or
a soft flexible wide tire at low pressure.

I'm not surprised, Jeff. Comparing the standard and the lightweight
folding Big Apples, and the thinner T19A tubes with the standard T19
tubes for 60x622 tyres, I found the lightweight versions to be very much
more comfortable with no degradation in handling and roadholding at the
limit, and not more fragile either on my rough but tarmacced lanes.
Handling is what the tyre does that is expected in response to normal
inputs up to the margin of error, roadholding is recovery from something
extreme stupid the rider does (or the road or environment does to him)
beyond the margin of error.

It must have been a common experience, because elements of the folding
Big Apple, and especially its ultra-flexible sidewall, were then spread
throughout the Big Apple range by Schwalbe, so that the folding tyre is
no longer a separate line within the brand.

Andre Jute
A life spent on the response of wheeled vehicles is not wasted. Sometimes
I wish I continued as a hot rodder all my life.


I tend to notice handling more than slight differences in rolling
resistance. Granted I’m not a racer trying to milk milliseconds from my
times. But cornering in a tight downhill is something I care about. My
HED wheels running 23mm conti folding tire at 90 psi are the sweet spot for
me. Comfortable and good handling. Just my two cents but I find the
discussion on rolling resistance without handling considered to be a bit
useless.

For a very different perspective, yesterday I took the gravel bike out
for a spin.

On the gravel bike - on gravel - rolling resistance takes on a much more
dominant role. Handling is more of an issue than on pavement. Never
mind efficiency, a harder/narrower rear tire gives so much bouncing and
skittering side-to-side that /control/ takes a lot more effort - and I'm
talking about riding in a straight line! I've found that good side lugs
on a tire help with the skittering - feels like the tire stays on top of
pieces of gravel rather than riding up and falling off sideways.

I've written before that the gravel in my county is pretty rough, though
that seems to vary by the week. Sometimes I'll find a nice hard-pack
track down the middle of the road, but I think the county just re-spread
gravel, 'cause it was all loose stuff yesterday.

There's no doubt I'm sinking a lot more energy into rolling resistance
than on a road bike. I can even quantify it a bit, being a data junkie
and having PowerTap wheels on both road and gravel bikes. On the road,
it takes a very brisk ride to burn over about 33-34 kiloJoules per mile.
Yesterday on the gravel, at a much lower speed, I averaged 35 kJ/mile.
This is for rides that start and end at the same elevation.

It's a topic for another post, but I find on the road that energy /per
mile/ is surprisingly consistent, ranging from around 27 kJ/mile for a
gentle pootle to maybe 35 kJ/mile for a very brisk hilly ride, with most
rides in the 30-33 range. Not, of course, on rides that start and end
at different elevations.

Lower pressure helps handling/skittering with the wider contact patch.
But the lower limit of tire pressure to avoid pinch flats seems to vary
by the minute; it all depends on what you hit, so there's no rule there
even for a given tire/rim/rider. I've only pinch flat once so far in
many rides, but I think it was a fluke rock hit.

The rims on my bike - Trek Checkpoint SL 5 - are really too narrow for
my tastes, but I took too long to figure that out. The bike came with
35mm tires, quickly swapped to 42mm. The tires are so much wider than
the rim, and run around 35-37psi, that they /always/ LOOK flat, even
when they're fine. Between the bounce of intentionally soft tires and
the vertical flex designed into the frame, the tires always /feel/ a bit
flat too, enough that I sometimes stop and check.

It's a good question what pressure I'd use on a comfort-be-damned
go-as-fast-as-possible ride, since I'm doing this for fun and I haven't
raced in many years.

Mark J.

I remember a few years ago a ride on our MTBs when we were coming home along a dirt road. A few kilometers along after turning onto another dirt road we discovered that it had just been freshly graveled. that gravel layer was deep and loose, so much do that it was hard io ride a straight line on my rigid MTB or my friend's front suspension MTB. Both had 26" x 2.125 or 2.25 knobby tires on them. On a skinny tire it'd have been impossible to ride that stretch or road.

Cheers

Fortunately, the local gravel is rarely /deep/ except toward the
shoulder. When a pickup approaches, I'll shift over a bit toward the
shoulder, and then I need to surge the power quite a bit to keep moving.

These encounters are rare; the locals don't seem to like driving on the
gravel much faster than I'm riding, so few encounters are overtakes. To
be clear, they're going SLOW, I'm not going fast. I suppose that's an
indicator how rough the gravel is.

Mark J.

On Mon, 6 Jul 2020 12:52:17 -0400, Frank Krygowski
wrote:

On 7/6/2020 2:02 AM, John B. wrote:
On Sun, 5 Jul 2020 22:13:14 -0400, Frank Krygowski
wrote:

On 7/5/2020 8:06 PM, AMuzi wrote:
On 7/5/2020 5:41 PM, Duane wrote:
Andre Jute wrote:
On Sunday, July 5, 2020 at 5:46:09 PM UTC+1, Jeff Liebermann wrote:
On Sat, 04 Jul 2020 19:21:20 -0700, Jeff Liebermann
wrote:

When you take the same rider and bike, and switch from slicks to
knobbies, you reduce the ground patch area.* That increases the ground
pressure, which causes the rolling resistance to increase.* That's one
reason why riding knobbies on pavement is like dragging an anchor.

I forgot to mumble something about tire pressu

"Everything You Think You Know About Bicycle Tire Pressure is Probably
Wrong"
https://www.roadbikerider.com/the-tire-pressure-revolution-by-jan-heine-d1/

Quoting:
Tire pressure has almost no effect on a tire’s speed.

If lower pressures don’t make tires slower, then you
can create wide tires with supple casings. You run
them at lower pressures, and you don’t give up any
performance on smooth roads. On rough roads, you
actually gain speed, because the tire (and you) bounce
less. And on all roads, you are more comfortable.

Conclusion
Tire pressure does not significantly affect your
bike’s rolling resistance, but the casing construction
of your tires does. This means that you can ride lower
pressures without going slower, and that wide tires
are no slower than narrow ones - as long as they have
similar casings. The fastest tires have supple casings
that consume less energy when they flex, and transmit
fewer vibrations, creating a win-win situation. These
tires roll super-fast no matter at what pressure you
run them.

So, you have a choice.* A hard stiff narrow tire at high pressure or
a soft flexible wide tire at low pressure.

I'm not surprised, Jeff. Comparing the standard and the lightweight
folding Big Apples, and the thinner T19A tubes with the standard T19
tubes for 60x622 tyres, I found the lightweight versions to be very much
more comfortable with no degradation in handling and roadholding at the
limit, and not more fragile either on my rough but tarmacced lanes.
Handling is what the tyre does that is expected in response to normal
inputs up to the margin of error, roadholding is recovery from something
extreme stupid the rider does (or the road or environment does to him)
beyond the margin of error.

It must have been a common experience, because elements of the folding
Big Apple, and especially its ultra-flexible sidewall, were then spread
throughout the Big Apple range by Schwalbe, so that the folding tyre is
no longer a separate line within the brand.

Andre Jute
A life spent on the response of wheeled vehicles is not wasted.
Sometimes
I wish I continued as a hot rodder all my life.


I tend to notice handling more than slight differences in rolling
resistance.* Granted I’m not a racer trying to milk milliseconds
from my
times.* But cornering in a tight downhill is something I care about.* My
HED wheels running 23mm conti folding tire at 90 psi are the sweet
spot for
me.* Comfortable and good handling.** Just my two cents but I find the
discussion on rolling resistance without handling considered to be a bit
useless.


+1

Except rolling resistance is quantifiable, at least to a degree.
Handling is a pretty nebulous item.

Similarly, I've been skeptical of Jan Heine's testimonies about bikes
that "plane" i.e. that have the precise degree of flexibility (not too
stiff) that allows the frame to somehow match his pedal strokes and go
faster with less effort. like a speedboat that planes over the water.

I'm not saying such a thing is impossible; but I'd like some hard
evidence "planing" exists other than his rave review. If some bikes
"plane" more than others, how can we measure it?

Likewise, if one tire "handles" better than others, how can we measure
it? Does anyone know if there is an actual metric?

Boats "plane" because they rise up out of the water and thus have far
less drag.

For a bicycle to "plane" it would require the bicycle to somehow
decrease it's "drag" in some manner to allow it to increase its speed.
Note that this can be accomplished by going from an erect position on
the bike to a "head down, over the bars" position and can be easily
demonstrated by coasting down a hill and changing one's position and
watching the speedometer :-)

I agree. Jan Heine doesn't seem to attribute "planing" of a bike to
reduced resistance. He seems to believe that a bike frame with just the
right flexibility - not too much, not too little - somehow flexes in
synchrony with his pedal strokes and allows him to put in more power
with less fatigue.

Absent measurements and data, I'm very skeptical.

I'm afraid the logic of the bike flexing in tune with pedal strokes
being easier to pedal seems, well, a bit far fetched, although it is
certainly possible that one bike might be faster for the same power
output, but I suspect that weight or weight distribution might be a
more important factor.

Another thing that I have read is that professional cyclists have a
pedal stroke that is down and back, a sort of backward "L" sort of
thing when pedaling normally which, if Heine is as adapt as a
professional would mean that the bike would have to flex in two
directions :-)
--
Cheers,

John B.

On Mon, 6 Jul 2020 10:15:27 -0700, "Mark J."
wrote:

On 7/5/2020 3:41 PM, Duane wrote:
Andre Jute wrote:
On Sunday, July 5, 2020 at 5:46:09 PM UTC+1, Jeff Liebermann wrote:
On Sat, 04 Jul 2020 19:21:20 -0700, Jeff Liebermann
wrote:

When you take the same rider and bike, and switch from slicks to
knobbies, you reduce the ground patch area. That increases the ground
pressure, which causes the rolling resistance to increase. That's one
reason why riding knobbies on pavement is like dragging an anchor.

I forgot to mumble something about tire pressu

"Everything You Think You Know About Bicycle Tire Pressure is Probably
Wrong"
https://www.roadbikerider.com/the-tire-pressure-revolution-by-jan-heine-d1/
Quoting:
Tire pressure has almost no effect on a tire’s speed.

If lower pressures don’t make tires slower, then you
can create wide tires with supple casings. You run
them at lower pressures, and you don’t give up any
performance on smooth roads. On rough roads, you
actually gain speed, because the tire (and you) bounce
less. And on all roads, you are more comfortable.

Conclusion
Tire pressure does not significantly affect your
bike’s rolling resistance, but the casing construction
of your tires does. This means that you can ride lower
pressures without going slower, and that wide tires
are no slower than narrow ones - as long as they have
similar casings. The fastest tires have supple casings
that consume less energy when they flex, and transmit
fewer vibrations, creating a win-win situation. These
tires roll super-fast no matter at what pressure you
run them.

So, you have a choice. A hard stiff narrow tire at high pressure or
a soft flexible wide tire at low pressure.

I'm not surprised, Jeff. Comparing the standard and the lightweight
folding Big Apples, and the thinner T19A tubes with the standard T19
tubes for 60x622 tyres, I found the lightweight versions to be very much
more comfortable with no degradation in handling and roadholding at the
limit, and not more fragile either on my rough but tarmacced lanes.
Handling is what the tyre does that is expected in response to normal
inputs up to the margin of error, roadholding is recovery from something
extreme stupid the rider does (or the road or environment does to him)
beyond the margin of error.

It must have been a common experience, because elements of the folding
Big Apple, and especially its ultra-flexible sidewall, were then spread
throughout the Big Apple range by Schwalbe, so that the folding tyre is
no longer a separate line within the brand.

Andre Jute
A life spent on the response of wheeled vehicles is not wasted. Sometimes
I wish I continued as a hot rodder all my life.


I tend to notice handling more than slight differences in rolling
resistance. Granted I’m not a racer trying to milk milliseconds from my
times. But cornering in a tight downhill is something I care about. My
HED wheels running 23mm conti folding tire at 90 psi are the sweet spot for
me. Comfortable and good handling. Just my two cents but I find the
discussion on rolling resistance without handling considered to be a bit
useless.

For a very different perspective, yesterday I took the gravel bike out
for a spin.

On the gravel bike - on gravel - rolling resistance takes on a much more
dominant role. Handling is more of an issue than on pavement. Never
mind efficiency, a harder/narrower rear tire gives so much bouncing and
skittering side-to-side that /control/ takes a lot more effort - and I'm
talking about riding in a straight line! I've found that good side lugs
on a tire help with the skittering - feels like the tire stays on top of
pieces of gravel rather than riding up and falling off sideways.

I've written before that the gravel in my county is pretty rough, though
that seems to vary by the week. Sometimes I'll find a nice hard-pack
track down the middle of the road, but I think the county just re-spread
gravel, 'cause it was all loose stuff yesterday.

There's no doubt I'm sinking a lot more energy into rolling resistance
than on a road bike. I can even quantify it a bit, being a data junkie
and having PowerTap wheels on both road and gravel bikes. On the road,
it takes a very brisk ride to burn over about 33-34 kiloJoules per mile.
Yesterday on the gravel, at a much lower speed, I averaged 35 kJ/mile.
This is for rides that start and end at the same elevation.

It's a topic for another post, but I find on the road that energy /per
mile/ is surprisingly consistent, ranging from around 27 kJ/mile for a
gentle pootle to maybe 35 kJ/mile for a very brisk hilly ride, with most
rides in the 30-33 range. Not, of course, on rides that start and end
at different elevations.

Doesn't wind resistance increase as a square of the velocity?
--
Cheers,

John B.

On Mon, 6 Jul 2020 10:41:58 -0700 (PDT), Lou Holtman
wrote:

On Monday, July 6, 2020 at 7:15:32 PM UTC+2, Mark J. wrote:



It's a topic for another post, but I find on the road that energy /per
mile/ is surprisingly consistent, ranging from around 27 kJ/mile for a
gentle pootle to maybe 35 kJ/mile for a very brisk hilly ride, with most
rides in the 30-33 range. Not, of course, on rides that start and end
at different elevations.


Tell that to the people that say that 10-20 Watt on average is insignificant.

Lou

Well, it is the difference between 0.01 and 0.02 H.P. :-)
--
Cheers,

John B.

On 7/6/2020 7:10 PM, John B. wrote:
On Mon, 6 Jul 2020 12:52:17 -0400, Frank Krygowski
wrote:

On 7/6/2020 2:02 AM, John B. wrote:
On Sun, 5 Jul 2020 22:13:14 -0400, Frank Krygowski
wrote:

On 7/5/2020 8:06 PM, AMuzi wrote:
On 7/5/2020 5:41 PM, Duane wrote:
Andre Jute wrote:
On Sunday, July 5, 2020 at 5:46:09 PM UTC+1, Jeff Liebermann wrote:
On Sat, 04 Jul 2020 19:21:20 -0700, Jeff Liebermann
wrote:

When you take the same rider and bike, and switch from slicks to
knobbies, you reduce the ground patch area. That increases the ground
pressure, which causes the rolling resistance to increase. That's one
reason why riding knobbies on pavement is like dragging an anchor.

I forgot to mumble something about tire pressu

"Everything You Think You Know About Bicycle Tire Pressure is Probably
Wrong"
https://www.roadbikerider.com/the-tire-pressure-revolution-by-jan-heine-d1/

Quoting:
Tire pressure has almost no effect on a tire’s speed.

If lower pressures don’t make tires slower, then you
can create wide tires with supple casings. You run
them at lower pressures, and you don’t give up any
performance on smooth roads. On rough roads, you
actually gain speed, because the tire (and you) bounce
less. And on all roads, you are more comfortable.

Conclusion
Tire pressure does not significantly affect your
bike’s rolling resistance, but the casing construction
of your tires does. This means that you can ride lower
pressures without going slower, and that wide tires
are no slower than narrow ones - as long as they have
similar casings. The fastest tires have supple casings
that consume less energy when they flex, and transmit
fewer vibrations, creating a win-win situation. These
tires roll super-fast no matter at what pressure you
run them.

So, you have a choice. A hard stiff narrow tire at high pressure or
a soft flexible wide tire at low pressure.

I'm not surprised, Jeff. Comparing the standard and the lightweight
folding Big Apples, and the thinner T19A tubes with the standard T19
tubes for 60x622 tyres, I found the lightweight versions to be very much
more comfortable with no degradation in handling and roadholding at the
limit, and not more fragile either on my rough but tarmacced lanes.
Handling is what the tyre does that is expected in response to normal
inputs up to the margin of error, roadholding is recovery from something
extreme stupid the rider does (or the road or environment does to him)
beyond the margin of error.

It must have been a common experience, because elements of the folding
Big Apple, and especially its ultra-flexible sidewall, were then spread
throughout the Big Apple range by Schwalbe, so that the folding tyre is
no longer a separate line within the brand.

Andre Jute
A life spent on the response of wheeled vehicles is not wasted.
Sometimes
I wish I continued as a hot rodder all my life.


I tend to notice handling more than slight differences in rolling
resistance. Granted I’m not a racer trying to milk milliseconds
from my
times. But cornering in a tight downhill is something I care about. My
HED wheels running 23mm conti folding tire at 90 psi are the sweet
spot for
me. Comfortable and good handling. Just my two cents but I find the
discussion on rolling resistance without handling considered to be a bit
useless.


+1

Except rolling resistance is quantifiable, at least to a degree.
Handling is a pretty nebulous item.

Similarly, I've been skeptical of Jan Heine's testimonies about bikes
that "plane" i.e. that have the precise degree of flexibility (not too
stiff) that allows the frame to somehow match his pedal strokes and go
faster with less effort. like a speedboat that planes over the water.

I'm not saying such a thing is impossible; but I'd like some hard
evidence "planing" exists other than his rave review. If some bikes
"plane" more than others, how can we measure it?

Likewise, if one tire "handles" better than others, how can we measure
it? Does anyone know if there is an actual metric?

Boats "plane" because they rise up out of the water and thus have far
less drag.

For a bicycle to "plane" it would require the bicycle to somehow
decrease it's "drag" in some manner to allow it to increase its speed.
Note that this can be accomplished by going from an erect position on
the bike to a "head down, over the bars" position and can be easily
demonstrated by coasting down a hill and changing one's position and
watching the speedometer :-)

I agree. Jan Heine doesn't seem to attribute "planing" of a bike to
reduced resistance. He seems to believe that a bike frame with just the
right flexibility - not too much, not too little - somehow flexes in
synchrony with his pedal strokes and allows him to put in more power
with less fatigue.

Absent measurements and data, I'm very skeptical.

I'm afraid the logic of the bike flexing in tune with pedal strokes
being easier to pedal seems, well, a bit far fetched, although it is
certainly possible that one bike might be faster for the same power
output, but I suspect that weight or weight distribution might be a
more important factor.

Another thing that I have read is that professional cyclists have a
pedal stroke that is down and back, a sort of backward "L" sort of
thing when pedaling normally which, if Heine is as adapt as a
professional would mean that the bike would have to flex in two
directions :-)
--
Cheers,

John B.


Bicycle frames flex in more directions than that; they twist
on different axes. Not sure what advantage that could
possibly offer...

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On 7/6/2020 1:15 PM, Mark J. wrote:


There's no doubt I'm sinking a lot more energy into rolling resistance
than on a road bike.Â* I can even quantify it a bit, being a data junkie
and having PowerTap wheels on both road and gravel bikes.Â* On the road,
it takes a very brisk ride to burn over about 33-34 kiloJoules per mile.
Â*Yesterday on the gravel, at a much lower speed, I averaged 35 kJ/mile.
Â*This is for rides that start and end at the same elevation.

It's a topic for another post, but I find on the road that energy /per
mile/ is surprisingly consistent, ranging from around 27 kJ/mile for a
gentle pootle to maybe 35 kJ/mile for a very brisk hilly ride, with most
rides in the 30-33 range.Â* Not, of course, on rides that start and end
at different elevations.

I don't recall coming across kJ/mile numbers before, but looking at the
units, they reduce to units of force. So what those numbers represent is
the average force applied to drive the bike forward over the course of
the ride. So that would equal the total drag force on the bike, more or
less - rolling resistance, air resistance, what's lost in jiggling the
rider's body, etc.

Working the conversions, I get 30 kJ/mile = 18.6 Newtons force, or 4.2
pounds drag force on the bike, on average.

Air drag varies as the square of speed; but I'd expect for a reasonable
variation in low-ish speeds, the air drag would be at least fairly
constant. I'm assuming you're not riding over 20 mph.


--
- Frank Krygowski

On 7/6/2020 8:22 PM, John B. wrote:
On Mon, 6 Jul 2020 10:41:58 -0700 (PDT), Lou Holtman
wrote:

On Monday, July 6, 2020 at 7:15:32 PM UTC+2, Mark J. wrote:



It's a topic for another post, but I find on the road that energy /per
mile/ is surprisingly consistent, ranging from around 27 kJ/mile for a
gentle pootle to maybe 35 kJ/mile for a very brisk hilly ride, with most
rides in the 30-33 range. Not, of course, on rides that start and end
at different elevations.


Tell that to the people that say that 10-20 Watt on average is insignificant.

Lou

Well, it is the difference between 0.01 and 0.02 H.P. :-)

The significance or lack of significance depends on your objectives.

--
- Frank Krygowski

John B. wrote:
On Mon, 6 Jul 2020 10:41:58 -0700 (PDT), Lou Holtman
wrote:

On Monday, July 6, 2020 at 7:15:32 PM UTC+2, Mark J. wrote:



It's a topic for another post, but I find on the road that energy /per
mile/ is surprisingly consistent, ranging from around 27 kJ/mile for a
gentle pootle to maybe 35 kJ/mile for a very brisk hilly ride, with most
rides in the 30-33 range. Not, of course, on rides that start and end
at different elevations.


Tell that to the people that say that 10-20 Watt on average is insignificant.

Lou

Well, it is the difference between 0.01 and 0.02 H.P. :-)
--
Cheers,

John B.



If 1000 W = 1 HP, yes...

On 7/6/2020 8:33 PM, AMuzi wrote:
On 7/6/2020 7:10 PM, John B. wrote:
On Mon, 6 Jul 2020 12:52:17 -0400, Frank Krygowski wrote:


I agree. Jan Heine doesn't seem to attribute "planing" of a bike to
reduced resistance. He seems to believe that a bike frame with just the
right flexibility - not too much, not too little - somehow flexes in
synchrony with his pedal strokes and allows him to put in more power
with less fatigue.

Absent measurements and data, I'm very skeptical.

I'm afraid the logic of the bike flexing in tune with pedal strokes
being easier to pedal seems, well, a bit far fetched, although it is
certainly possible that one bike might be faster for the same power
output, but I suspect that weight or weight distribution might be a
more important factor.

Another thing that I have read is that professional cyclists have a
pedal stroke that is down and back, a sort of backward "L" sort of
thing when pedaling normally which, if Heine is as adapt as a
professional would mean that the bike would have to flex in two
directions :-)
--
Cheers,

John B.


Bicycle frames flex in more directions than that; they twist on
different axes.* Not sure what advantage that could possibly offer...

I'm not sure either. I suppose tastes may differ, but I really like a
very stiff frame, at least for sporty riding.

As we've discussed in the past, high-budget international races have
been won on super-flexible things like Alan frames. They've also been
won on super-stiff frames. But I prefer when the bottom bracket says
parallel to the rear axle.

--
- Frank Krygowski