Steel is Real and Carbon is Lighter

On Thursday, June 20, 2019 at 2:29:04 PM UTC+2, AMuzi wrote:
On 6/20/2019 5:21 AM, Duane wrote:
Sir Ridesalot wrote:
On Wednesday, June 19, 2019 at 8:32:05 PM UTC-4, Frank Krygowski wrote:
On 6/19/2019 7:45 PM, jbeattie wrote:
On Wednesday, June 19, 2019 at 11:18:52 AM UTC-7, Frank Krygowski wrote:
On 6/19/2019 10:25 AM, jbeattie wrote:
On Tuesday, June 18, 2019 at 8:06:37 PM UTC-7, Frank Krygowski wrote:
On 6/18/2019 1:24 PM, jbeattie wrote:
On Tuesday, June 18, 2019 at 9:49:50 AM UTC-7, Frank Krygowski wrote:

For ordinary riding? No, most tiny improvements make no noticeable
difference. Even though we all know the near-magic power of red paint.


What is a "tiny improvement"? The frame on my Emonda probably
weighs less than the Columbus steel forks off my last custom racing
bike. Those things were suitable for clubbing baby harp seals or
home defense. Weight and stiffness do matter when climbing. If
we're talking about aero bits, that's harder call -- except that
dopes on aero bars riding in packs can result in a massive
worsening of your riding experience. Wearing aero shoe covers may
keep your feet warmer on chilly mornings, which might make you
faster. It all adds up.

Stiffness probably does not make a detectable difference, unless the
frame is so flexible that things are scraping. Remember the discussion
we had about the bike magazine's test of modern stiff CF frames vs.
older, heavier steel frames? The test riders gushed about how the
stiffness improved their climbing, but the math showed the speed
difference was precisely what would be predicted by the weight difference.

Weight matters when climbing. If getting to the top of the hill before
your buddy is really, really important, a lighter bike will help by
whatever the percent difference in total bike+rider weight. If a 160
pound rider changes his 20 pound bike for an 18 pound bike, he should be
about 1% faster up a steep hill. Whoopee!

Make that a 5lb weight difference. You need to borrow a well-fitting
modern 15lb racing bike with an appropriate gear range and then do a
long ride with lots of hills. It's not a subtle or imagined
difference compared to a T1000 or old-school steel sport touring
bike, particularly if you're trying to keep up with others.

Again, I'm not saying the weight doesn't make a difference! The
difference it makes on an uphill is the percentage difference in
bike+rider weight.

Does nobody remember the discussion a couple years ago where the
magazine article's data proved that? They put young racers on modern CF
bikes, then on 1980s steel racing bikes and timed them up long hills.
The speed difference was exactly what the weight difference predicted.

Think about changing to a bike that was five pounds lighter, but then
strapped a five pound weight around your waist. Hopefully people here
wouldn't think you'd still be way faster up the hills, right?

And again, the stiffness, the snappiness, the magical handling of a CF
bike made no difference at all in that comparison test. There were other
details the youngsters liked on the new bikes - as in "I was afraid to
take my hands off the hoods to shift" - but the speed difference was
apparently due to the weight.

If others think there's some other energy savings or power increase,
please explain it in engineering or scientific terms. Explain how it's
not magic.

Well, go to all the reviews of retro bikes on GCN. E.g.
https://www.youtube.com/watch?v=V4JAvQCp8ww Again, go borrow a 15lb
modern racing bike that fits, then do hill repeats. Now do that on a
Biketown bike. Really, there is no difference! It's all placebo
effect! Now do it on a Surly Moonlander. No difference!

At what point would you agree there is a difference -- and why that
point? Even without almighty "data" (presumably something created by a
machine and not anecdotal reports), most of us would agree that some
bikes are dogs and others aren't.

Geez, guys, you're very diligent about confusing yourselves!

As I told Sir, I'm _not_ saying weight doesn't make a difference! I'm
quantifying that difference.

Didn't we all meet guys in the 1970s who thought "My new bike has six
cogs instead of five, so it's going to be 20% faster"? Don't we still
meet guys who think 11 cogs will be 10% faster than ten cogs? But that's
silly and very unscientific. It shows a poor grasp of basic physics

In the same way, there seem to be people who think "My old bike weighed
20 pounds but my new bike is 18 pounds. It's going to be 10% faster up a
hill."

Sorry! What matters is total weight, bike+rider. a 160 pound guy who
goes from a 20 pound bike to an 18 pound bike has lost 2 out of 180
pounds. He's improved the total weight by about 1%.

Will it make a difference? Yes, a difference of about 1%. So weight
_does_ matter - that much.

"Oh, but try a bike that's FIVE pounds lighter!!" OK, that one will be
2.8% better. It won't be 25% better.

If 1% or 2.8% is worth it to you, fine. It is to some people. Other
people may have a different view.

BTW, the first national bike convention we ever attended was 1978 in
Michigan. Since we lived in an area where we knew only one other avid
cyclist, I was fascinated by all the beautiful high-end bikes.

But one weird one was a guy on a super light custom frame, with the
highest end and lightest SunTour components, many of which he had
drilled holes in. Super light rims with tubular tires, too. He was just
in awe of his own bike, telling people over and over how little it
weighed (somewhere under 20 pounds).

Then the big mass start parade into town started. I watched carefully as
he started out, because I wanted proof it would support him. I guessed
he weighted somewhere around 300 pounds, and very little of it was muscle.

--
- Frank Krygowski

The lighter weight and more cogs with the same or very similar high and
low gears means there's less of a jump between each cog. Therefore an 11
cogs cogset would be more efficient than a 7 cogs cogset because the
rider won't spin out when changing gears or have to pedal harder than
he/she would if the jumps between gears were larger.

I've even built up a 9 cogs corncob 11-19 teeth cogset for my skinny tire
drop-bar MTB because the small incremental jumps between gears makes
riding the rolling hills around here more efficient and thus more
enjoyable. Once again your mileage varies and so does your needs and/or
wants but that doesn't mean that those who have and enjoy riding a very
lightweight bicycle with 11 or even m ore cogs is wrong to do so.

It's different strokes for different folks.

Oh, another thing. I have another bicycle with 9 cogs on it. I have it
set up with 7 fairly close cogs and 2 bailout/wind/steep hills cogs. It
gives me the best of a 7 cogs setup plus those two bailout gears.

Cheers


I’ve never heard anyone say that 11 speed is faster than 10. More
efficient, more choice, less need to switch rings, smoother transition
etc. I guess in a race given a specific combination of chain rings and
cassette it’s possible.


Indeed. Even for me having an 18 & a 19 is a big feature
not reasonable to a 4 speed or five speed freewheel.

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

Exactly. You don't need 11 speed. Here on the flats I only need 4 gears. In early season 19-18-17-16 and mid season 18-17-16-15. But I go with the flow and have a 11 speed 12-25 cassette, 12-13-14-15-16-17-18-19-21-23-25. There is really no downside. Yeah, yeah, cost and wear bla, bla bla. All nonsense from people who actually never used it.

Lou

On 6/20/2019 10:23 AM, jbeattie wrote:
On Wednesday, June 19, 2019 at 5:32:05 PM UTC-7, Frank Krygowski wrote:
On 6/19/2019 7:45 PM, jbeattie wrote:
On Wednesday, June 19, 2019 at 11:18:52 AM UTC-7, Frank Krygowski wrote:
On 6/19/2019 10:25 AM, jbeattie wrote:
On Tuesday, June 18, 2019 at 8:06:37 PM UTC-7, Frank Krygowski wrote:
On 6/18/2019 1:24 PM, jbeattie wrote:
On Tuesday, June 18, 2019 at 9:49:50 AM UTC-7, Frank Krygowski wrote:

For ordinary riding? No, most tiny improvements make no noticeable
difference. Even though we all know the near-magic power of red paint.


What is a "tiny improvement"? The frame on my Emonda probably weighs less than the Columbus steel forks off my last custom racing bike. Those things were suitable for clubbing baby harp seals or home defense. Weight and stiffness do matter when climbing. If we're talking about aero bits, that's harder call -- except that dopes on aero bars riding in packs can result in a massive worsening of your riding experience. Wearing aero shoe covers may keep your feet warmer on chilly mornings, which might make you faster. It all adds up.

Stiffness probably does not make a detectable difference, unless the
frame is so flexible that things are scraping. Remember the discussion
we had about the bike magazine's test of modern stiff CF frames vs.
older, heavier steel frames? The test riders gushed about how the
stiffness improved their climbing, but the math showed the speed
difference was precisely what would be predicted by the weight difference.

Weight matters when climbing. If getting to the top of the hill before
your buddy is really, really important, a lighter bike will help by
whatever the percent difference in total bike+rider weight. If a 160
pound rider changes his 20 pound bike for an 18 pound bike, he should be
about 1% faster up a steep hill. Whoopee!

Make that a 5lb weight difference. You need to borrow a well-fitting modern 15lb racing bike with an appropriate gear range and then do a long ride with lots of hills. It's not a subtle or imagined difference compared to a T1000 or old-school steel sport touring bike, particularly if you're trying to keep up with others.

Again, I'm not saying the weight doesn't make a difference! The
difference it makes on an uphill is the percentage difference in
bike+rider weight.

Does nobody remember the discussion a couple years ago where the
magazine article's data proved that? They put young racers on modern CF
bikes, then on 1980s steel racing bikes and timed them up long hills.
The speed difference was exactly what the weight difference predicted.

Think about changing to a bike that was five pounds lighter, but then
strapped a five pound weight around your waist. Hopefully people here
wouldn't think you'd still be way faster up the hills, right?

And again, the stiffness, the snappiness, the magical handling of a CF
bike made no difference at all in that comparison test. There were other
details the youngsters liked on the new bikes - as in "I was afraid to
take my hands off the hoods to shift" - but the speed difference was
apparently due to the weight.

If others think there's some other energy savings or power increase,
please explain it in engineering or scientific terms. Explain how it's
not magic.

Well, go to all the reviews of retro bikes on GCN. E.g. https://www.youtube.com/watch?v=V4JAvQCp8ww Again, go borrow a 15lb modern racing bike that fits, then do hill repeats. Now do that on a Biketown bike. Really, there is no difference! It's all placebo effect! Now do it on a Surly Moonlander. No difference!

At what point would you agree there is a difference -- and why that point? Even without almighty "data" (presumably something created by a machine and not anecdotal reports), most of us would agree that some bikes are dogs and others aren't.

Geez, guys, you're very diligent about confusing yourselves!

As I told Sir, I'm _not_ saying weight doesn't make a difference! I'm
quantifying that difference.

Didn't we all meet guys in the 1970s who thought "My new bike has six
cogs instead of five, so it's going to be 20% faster"? Don't we still
meet guys who think 11 cogs will be 10% faster than ten cogs? But that's
silly and very unscientific. It shows a poor grasp of basic physics

In the same way, there seem to be people who think "My old bike weighed
20 pounds but my new bike is 18 pounds. It's going to be 10% faster up a
hill."

Sorry! What matters is total weight, bike+rider. a 160 pound guy who
goes from a 20 pound bike to an 18 pound bike has lost 2 out of 180
pounds. He's improved the total weight by about 1%.

Will it make a difference? Yes, a difference of about 1%. So weight
_does_ matter - that much.

"Oh, but try a bike that's FIVE pounds lighter!!" OK, that one will be
2.8% better. It won't be 25% better.

If 1% or 2.8% is worth it to you, fine. It is to some people. Other
people may have a different view....

Applying a formula and coming up with a "percentage better" based on total bicycle and rider weight is deceptive. A better paradigm is lifting weights -- moving 15 pounds uphill rather than 20.

Sorry, Jay. Lifting weights is probably the worst analogy for your position.

Picking a weight lifting exercise at random: How many times can you curl
20 pounds? Maybe 30 times? So if you reduce the weight to 15 pounds, you
can curl it many times more, right?

Sure. But that's because that is essentially ALL that you are lifting!
The only other weight is that of your forearm, and it's close to negligible.

When you lift (AKA pedal) your 15 pound bike up the hill, it's the
_bike's_ weight that's close to negligible. The main problem is your own
160 - 180 pounds, or whatever you weigh. It's the opposite of weight
lifting.


You have to determine the additional energy needed to move that weight and how the additional energy affects the rider over time. Energy needed may depend on frame flex, tires and a number of other factors that are bicycle dependent.

My whole point is that the energy needed to move that weight uphill is
easily quantified. And the way most non-mathematical people visualize it
is wrong.

Tires? Yes, that effect if fairly easily quantified as well. Not
perfectly, at least as it's usually done, because standard rolling
resistance data measures only the part of the relevant losses within the
tire. But at least the rolling resistance issue doesn't get the same
blatant mistake that weight does. IOW, people don't seem to think "These
tires have a CRR of 0.003, and my old ones were 0.004, so I'm going to
be 25% faster."

Frame flex? I'm not aware of any serious attempt to quantify increases
in speed due to stiffening a frame. I like a stiff frame, but I suspect
it's roughly as effective as painting the bike red.

The effect on the rider depends on many things. We are not constant speed motors. Assuming a rider is attempting to maintain the same speed on a heavier and less efficient bike, the additional effort may be enough to exhaust him or her before the top of a climb -- which turns the last miles into a creep-along. Time is not off by 2% based on some formula but is off by more -- depending on how badly he or she blows. When you run the tank out, you could end up walking the last miles or sitting under a tree and resting.

First, understand that when I say 2% weight reduction yields about 2%
speed, I'm talking about climbing speed. So your total time is not "off
by 2%." Total time is probably off by a lot less, since on the level, a
2% weight reduction causes a benefit of only 2% times your rolling
resistance coefficient. That's maybe 0.02 * 0.004 = 0.008%, roughly. And
on a downhill, less weight means you descend a tiny bit slower.

I think the real and important thing at work is psychology. Riders are
swearing they ride much better with a bike that's a couple pounds
lighter. Some are claiming they ride much better if there's an extra
cog; or if there's exactly the right cog, like a 17 instead of an 18,
for whatever percentage of the ride that actually uses that cog. Or they
ride much better if the fork is stiffer; or they have their best shorts,
or their lucky socks, or their new paint job.

But I know I've had good days and bad days, even on the same day. There
was a day last year when I was telling people "I'm going to have to head
back home. I just don't have it today, I can't keep up." I was urged to
keep going and I slaved along just to hold someone's draft, until about
seven miles from the end, when I suddenly felt great. The leader said
"You took off like a bat out of hell!"

Well, it wasn't because my bike lost five pounds, or my tires suddenly
rolled better or my handlebar bag lost its air resistance. It just
happened.

If a couple pounds less bike makes it way more fun for you, that's fine.
But at a certain point, maybe this discussion should move from
rec.bicycles.tech to rec.bicycles.psychology

--
- Frank Krygowski

On 6/19/2019 10:07 PM, John B. Slocomb wrote:

I recently came across a "Bicycle Calculator"
http://bikecalculator.com/wattsUS.html
and tried a comparison of a 150 lb rider on a 22 lb bicycle versus a
150 lb rider on a 44 lb bicycle over a 20 mile distance with zero
elevation change. The 22 lb bike rider produced 100 watts of power and
required 80 minutes and burned 459 kcalories. the 44 lb rider
developed 103 watts of power, required 80 minutes and burned 474
kcalories.

An increase of 3% in energy expended requirement for doubling the
weight of the bike...

Yes, let's play with that calculator. On the "power from speed" version,
I put in 10% grade, 10 mph, I used their 150 pound rider and tried a 20
pound bike, an 18 pound bike and a 15 pound bike.

20 lb: 395 Watts. (Yes, that's a lot!). 18 lb: 391W. 15 lb: 384W.
So dropping two pounds yielded a 1.1% benefit. Dropping five pounds
yielded a 2.8% benefit.

I tried it the other way, "speed from power." Same rider, same bikes,
same grade, but I throttled back to a tough but reasonable 200 Watts.

20 lb bike: 5.27 mph. 18 lb: 5.33 mph. 15 lb: 5.42 mph.
Once again, percent benefits were 1.1% and 2.8%.

Those benefit estimates should sound familiar if you read upthread. I
did my (easy) manual calculations for a 160 pound rider, hence the tiny
discrepancy.

Ride what you like. But this is how much difference it's likely to make
on uphills. It will make less difference elsewhere.


--
- Frank Krygowski

On Thursday, June 20, 2019 at 9:23:12 AM UTC-7, Frank Krygowski wrote:
On 6/20/2019 10:23 AM, jbeattie wrote:
On Wednesday, June 19, 2019 at 5:32:05 PM UTC-7, Frank Krygowski wrote:
On 6/19/2019 7:45 PM, jbeattie wrote:
On Wednesday, June 19, 2019 at 11:18:52 AM UTC-7, Frank Krygowski wrote:
On 6/19/2019 10:25 AM, jbeattie wrote:
On Tuesday, June 18, 2019 at 8:06:37 PM UTC-7, Frank Krygowski wrote:
On 6/18/2019 1:24 PM, jbeattie wrote:
On Tuesday, June 18, 2019 at 9:49:50 AM UTC-7, Frank Krygowski wrote:

For ordinary riding? No, most tiny improvements make no noticeable
difference. Even though we all know the near-magic power of red paint.


What is a "tiny improvement"? The frame on my Emonda probably weighs less than the Columbus steel forks off my last custom racing bike. Those things were suitable for clubbing baby harp seals or home defense. Weight and stiffness do matter when climbing. If we're talking about aero bits, that's harder call -- except that dopes on aero bars riding in packs can result in a massive worsening of your riding experience. Wearing aero shoe covers may keep your feet warmer on chilly mornings, which might make you faster. It all adds up.

Stiffness probably does not make a detectable difference, unless the
frame is so flexible that things are scraping. Remember the discussion
we had about the bike magazine's test of modern stiff CF frames vs..
older, heavier steel frames? The test riders gushed about how the
stiffness improved their climbing, but the math showed the speed
difference was precisely what would be predicted by the weight difference.

Weight matters when climbing. If getting to the top of the hill before
your buddy is really, really important, a lighter bike will help by
whatever the percent difference in total bike+rider weight. If a 160
pound rider changes his 20 pound bike for an 18 pound bike, he should be
about 1% faster up a steep hill. Whoopee!

Make that a 5lb weight difference. You need to borrow a well-fitting modern 15lb racing bike with an appropriate gear range and then do a long ride with lots of hills. It's not a subtle or imagined difference compared to a T1000 or old-school steel sport touring bike, particularly if you're trying to keep up with others.

Again, I'm not saying the weight doesn't make a difference! The
difference it makes on an uphill is the percentage difference in
bike+rider weight.

Does nobody remember the discussion a couple years ago where the
magazine article's data proved that? They put young racers on modern CF
bikes, then on 1980s steel racing bikes and timed them up long hills..
The speed difference was exactly what the weight difference predicted.

Think about changing to a bike that was five pounds lighter, but then
strapped a five pound weight around your waist. Hopefully people here
wouldn't think you'd still be way faster up the hills, right?

And again, the stiffness, the snappiness, the magical handling of a CF
bike made no difference at all in that comparison test. There were other
details the youngsters liked on the new bikes - as in "I was afraid to
take my hands off the hoods to shift" - but the speed difference was
apparently due to the weight.

If others think there's some other energy savings or power increase,
please explain it in engineering or scientific terms. Explain how it's
not magic.

Well, go to all the reviews of retro bikes on GCN. E.g. https://www.youtube.com/watch?v=V4JAvQCp8ww Again, go borrow a 15lb modern racing bike that fits, then do hill repeats. Now do that on a Biketown bike. Really, there is no difference! It's all placebo effect! Now do it on a Surly Moonlander. No difference!

At what point would you agree there is a difference -- and why that point? Even without almighty "data" (presumably something created by a machine and not anecdotal reports), most of us would agree that some bikes are dogs and others aren't.

Geez, guys, you're very diligent about confusing yourselves!

As I told Sir, I'm _not_ saying weight doesn't make a difference! I'm
quantifying that difference.

Didn't we all meet guys in the 1970s who thought "My new bike has six
cogs instead of five, so it's going to be 20% faster"? Don't we still
meet guys who think 11 cogs will be 10% faster than ten cogs? But that's
silly and very unscientific. It shows a poor grasp of basic physics

In the same way, there seem to be people who think "My old bike weighed
20 pounds but my new bike is 18 pounds. It's going to be 10% faster up a
hill."

Sorry! What matters is total weight, bike+rider. a 160 pound guy who
goes from a 20 pound bike to an 18 pound bike has lost 2 out of 180
pounds. He's improved the total weight by about 1%.

Will it make a difference? Yes, a difference of about 1%. So weight
_does_ matter - that much.

"Oh, but try a bike that's FIVE pounds lighter!!" OK, that one will be
2.8% better. It won't be 25% better.

If 1% or 2.8% is worth it to you, fine. It is to some people. Other
people may have a different view....

Applying a formula and coming up with a "percentage better" based on total bicycle and rider weight is deceptive. A better paradigm is lifting weights -- moving 15 pounds uphill rather than 20.

Sorry, Jay. Lifting weights is probably the worst analogy for your position.

Picking a weight lifting exercise at random: How many times can you curl
20 pounds? Maybe 30 times? So if you reduce the weight to 15 pounds, you
can curl it many times more, right?

Sure. But that's because that is essentially ALL that you are lifting!
The only other weight is that of your forearm, and it's close to negligible.

When you lift (AKA pedal) your 15 pound bike up the hill, it's the
_bike's_ weight that's close to negligible. The main problem is your own
160 - 180 pounds, or whatever you weigh. It's the opposite of weight
lifting.


You have to determine the additional energy needed to move that weight and how the additional energy affects the rider over time. Energy needed may depend on frame flex, tires and a number of other factors that are bicycle dependent.

My whole point is that the energy needed to move that weight uphill is
easily quantified. And the way most non-mathematical people visualize it
is wrong.

Tires? Yes, that effect if fairly easily quantified as well. Not
perfectly, at least as it's usually done, because standard rolling
resistance data measures only the part of the relevant losses within the
tire. But at least the rolling resistance issue doesn't get the same
blatant mistake that weight does. IOW, people don't seem to think "These
tires have a CRR of 0.003, and my old ones were 0.004, so I'm going to
be 25% faster."

Frame flex? I'm not aware of any serious attempt to quantify increases
in speed due to stiffening a frame. I like a stiff frame, but I suspect
it's roughly as effective as painting the bike red.

The effect on the rider depends on many things. We are not constant speed motors. Assuming a rider is attempting to maintain the same speed on a heavier and less efficient bike, the additional effort may be enough to exhaust him or her before the top of a climb -- which turns the last miles into a creep-along. Time is not off by 2% based on some formula but is off by more -- depending on how badly he or she blows. When you run the tank out, you could end up walking the last miles or sitting under a tree and resting.

First, understand that when I say 2% weight reduction yields about 2%
speed, I'm talking about climbing speed. So your total time is not "off
by 2%." Total time is probably off by a lot less, since on the level, a
2% weight reduction causes a benefit of only 2% times your rolling
resistance coefficient. That's maybe 0.02 * 0.004 = 0.008%, roughly. And
on a downhill, less weight means you descend a tiny bit slower.

I think the real and important thing at work is psychology. Riders are
swearing they ride much better with a bike that's a couple pounds
lighter. Some are claiming they ride much better if there's an extra
cog; or if there's exactly the right cog, like a 17 instead of an 18,
for whatever percentage of the ride that actually uses that cog. Or they
ride much better if the fork is stiffer; or they have their best shorts,
or their lucky socks, or their new paint job.

But I know I've had good days and bad days, even on the same day. There
was a day last year when I was telling people "I'm going to have to head
back home. I just don't have it today, I can't keep up." I was urged to
keep going and I slaved along just to hold someone's draft, until about
seven miles from the end, when I suddenly felt great. The leader said
"You took off like a bat out of hell!"

Well, it wasn't because my bike lost five pounds, or my tires suddenly
rolled better or my handlebar bag lost its air resistance. It just
happened.

If a couple pounds less bike makes it way more fun for you, that's fine.
But at a certain point, maybe this discussion should move from
rec.bicycles.tech to rec.bicycles.psychology

If you put two pounds on your bike, you are lifting -- or moving, however you want to characterize it -- two more pounds. It may represent a small fraction of rider/bike weight, but the problem with analyzing this mathematically is that rider weight produces power and bottle weight doesn't. The effect of the additional weight is rider dependent. That's all I'm saying. Doing this as a math experiment doesn't work.

Assume on your best day and lightest bike that you are red-lining keeping up with the group on a climb. Then you add lets say 5 pounds by riding your swampy, soft gravel bike. You will go beyond red-lining to hold on, and then you will blow. You will be catching your breath, slowing down so your heart doesn't explode and pondering a call to Uber. You will not be off by some linear amount of time produced by a mathematical formula. You will be stopping for a picnic.

How do I know? I've been through this many times switching back and forth between bikes and riding with the same guys who have been kicking my ass for decades. And then there are more subtle differences in efficiency between bikes of similar weight. My gravel bike is probably a pound lighter than my super rain bike Synapse which has fenders and a lot of do-dads, but the Synapse is far stiffer everywhere. It sprints way better. The gravel bike has a super-swampy rear end that feels like a '70s touring bike (which is the whole idea), and climbing hard out of the saddle produces a lot of flex. Its just a sloppier, slower bike, particularly with gravel tires.

-- Jay Beattie.

On 6/20/2019 1:26 PM, jbeattie wrote:
On Thursday, June 20, 2019 at 9:23:12 AM UTC-7, Frank Krygowski wrote:
On 6/20/2019 10:23 AM, jbeattie wrote:
On Wednesday, June 19, 2019 at 5:32:05 PM UTC-7, Frank Krygowski wrote:
On 6/19/2019 7:45 PM, jbeattie wrote:
On Wednesday, June 19, 2019 at 11:18:52 AM UTC-7, Frank Krygowski wrote:
On 6/19/2019 10:25 AM, jbeattie wrote:
On Tuesday, June 18, 2019 at 8:06:37 PM UTC-7, Frank Krygowski wrote:
On 6/18/2019 1:24 PM, jbeattie wrote:
On Tuesday, June 18, 2019 at 9:49:50 AM UTC-7, Frank Krygowski wrote:

For ordinary riding? No, most tiny improvements make no noticeable
difference. Even though we all know the near-magic power of red paint.


What is a "tiny improvement"? The frame on my Emonda probably weighs less than the Columbus steel forks off my last custom racing bike. Those things were suitable for clubbing baby harp seals or home defense. Weight and stiffness do matter when climbing. If we're talking about aero bits, that's harder call -- except that dopes on aero bars riding in packs can result in a massive worsening of your riding experience. Wearing aero shoe covers may keep your feet warmer on chilly mornings, which might make you faster. It all adds up.

Stiffness probably does not make a detectable difference, unless the
frame is so flexible that things are scraping. Remember the discussion
we had about the bike magazine's test of modern stiff CF frames vs.
older, heavier steel frames? The test riders gushed about how the
stiffness improved their climbing, but the math showed the speed
difference was precisely what would be predicted by the weight difference.

Weight matters when climbing. If getting to the top of the hill before
your buddy is really, really important, a lighter bike will help by
whatever the percent difference in total bike+rider weight. If a 160
pound rider changes his 20 pound bike for an 18 pound bike, he should be
about 1% faster up a steep hill. Whoopee!

Make that a 5lb weight difference. You need to borrow a well-fitting modern 15lb racing bike with an appropriate gear range and then do a long ride with lots of hills. It's not a subtle or imagined difference compared to a T1000 or old-school steel sport touring bike, particularly if you're trying to keep up with others.

Again, I'm not saying the weight doesn't make a difference! The
difference it makes on an uphill is the percentage difference in
bike+rider weight.

Does nobody remember the discussion a couple years ago where the
magazine article's data proved that? They put young racers on modern CF
bikes, then on 1980s steel racing bikes and timed them up long hills.
The speed difference was exactly what the weight difference predicted.

Think about changing to a bike that was five pounds lighter, but then
strapped a five pound weight around your waist. Hopefully people here
wouldn't think you'd still be way faster up the hills, right?

And again, the stiffness, the snappiness, the magical handling of a CF
bike made no difference at all in that comparison test. There were other
details the youngsters liked on the new bikes - as in "I was afraid to
take my hands off the hoods to shift" - but the speed difference was
apparently due to the weight.

If others think there's some other energy savings or power increase,
please explain it in engineering or scientific terms. Explain how it's
not magic.

Well, go to all the reviews of retro bikes on GCN. E.g. https://www.youtube.com/watch?v=V4JAvQCp8ww Again, go borrow a 15lb modern racing bike that fits, then do hill repeats. Now do that on a Biketown bike. Really, there is no difference! It's all placebo effect! Now do it on a Surly Moonlander. No difference!

At what point would you agree there is a difference -- and why that point? Even without almighty "data" (presumably something created by a machine and not anecdotal reports), most of us would agree that some bikes are dogs and others aren't.

Geez, guys, you're very diligent about confusing yourselves!

As I told Sir, I'm _not_ saying weight doesn't make a difference! I'm
quantifying that difference.

Didn't we all meet guys in the 1970s who thought "My new bike has six
cogs instead of five, so it's going to be 20% faster"? Don't we still
meet guys who think 11 cogs will be 10% faster than ten cogs? But that's
silly and very unscientific. It shows a poor grasp of basic physics

In the same way, there seem to be people who think "My old bike weighed
20 pounds but my new bike is 18 pounds. It's going to be 10% faster up a
hill."

Sorry! What matters is total weight, bike+rider. a 160 pound guy who
goes from a 20 pound bike to an 18 pound bike has lost 2 out of 180
pounds. He's improved the total weight by about 1%.

Will it make a difference? Yes, a difference of about 1%. So weight
_does_ matter - that much.

"Oh, but try a bike that's FIVE pounds lighter!!" OK, that one will be
2.8% better. It won't be 25% better.

If 1% or 2.8% is worth it to you, fine. It is to some people. Other
people may have a different view....

Applying a formula and coming up with a "percentage better" based on total bicycle and rider weight is deceptive. A better paradigm is lifting weights -- moving 15 pounds uphill rather than 20.

Sorry, Jay. Lifting weights is probably the worst analogy for your position.

Picking a weight lifting exercise at random: How many times can you curl
20 pounds? Maybe 30 times? So if you reduce the weight to 15 pounds, you
can curl it many times more, right?

Sure. But that's because that is essentially ALL that you are lifting!
The only other weight is that of your forearm, and it's close to negligible.

When you lift (AKA pedal) your 15 pound bike up the hill, it's the
_bike's_ weight that's close to negligible. The main problem is your own
160 - 180 pounds, or whatever you weigh. It's the opposite of weight
lifting.


You have to determine the additional energy needed to move that weight and how the additional energy affects the rider over time. Energy needed may depend on frame flex, tires and a number of other factors that are bicycle dependent.

My whole point is that the energy needed to move that weight uphill is
easily quantified. And the way most non-mathematical people visualize it
is wrong.

Tires? Yes, that effect if fairly easily quantified as well. Not
perfectly, at least as it's usually done, because standard rolling
resistance data measures only the part of the relevant losses within the
tire. But at least the rolling resistance issue doesn't get the same
blatant mistake that weight does. IOW, people don't seem to think "These
tires have a CRR of 0.003, and my old ones were 0.004, so I'm going to
be 25% faster."

Frame flex? I'm not aware of any serious attempt to quantify increases
in speed due to stiffening a frame. I like a stiff frame, but I suspect
it's roughly as effective as painting the bike red.

The effect on the rider depends on many things. We are not constant speed motors. Assuming a rider is attempting to maintain the same speed on a heavier and less efficient bike, the additional effort may be enough to exhaust him or her before the top of a climb -- which turns the last miles into a creep-along. Time is not off by 2% based on some formula but is off by more -- depending on how badly he or she blows. When you run the tank out, you could end up walking the last miles or sitting under a tree and resting.

First, understand that when I say 2% weight reduction yields about 2%
speed, I'm talking about climbing speed. So your total time is not "off
by 2%." Total time is probably off by a lot less, since on the level, a
2% weight reduction causes a benefit of only 2% times your rolling
resistance coefficient. That's maybe 0.02 * 0.004 = 0.008%, roughly. And
on a downhill, less weight means you descend a tiny bit slower.

I think the real and important thing at work is psychology. Riders are
swearing they ride much better with a bike that's a couple pounds
lighter. Some are claiming they ride much better if there's an extra
cog; or if there's exactly the right cog, like a 17 instead of an 18,
for whatever percentage of the ride that actually uses that cog. Or they
ride much better if the fork is stiffer; or they have their best shorts,
or their lucky socks, or their new paint job.

But I know I've had good days and bad days, even on the same day. There
was a day last year when I was telling people "I'm going to have to head
back home. I just don't have it today, I can't keep up." I was urged to
keep going and I slaved along just to hold someone's draft, until about
seven miles from the end, when I suddenly felt great. The leader said
"You took off like a bat out of hell!"

Well, it wasn't because my bike lost five pounds, or my tires suddenly
rolled better or my handlebar bag lost its air resistance. It just
happened.

If a couple pounds less bike makes it way more fun for you, that's fine.
But at a certain point, maybe this discussion should move from
rec.bicycles.tech to rec.bicycles.psychology

If you put two pounds on your bike, you are lifting -- or moving, however you want to characterize it -- two more pounds. It may represent a small fraction of rider/bike weight, but the problem with analyzing this mathematically is that rider weight produces power and bottle weight doesn't. The effect of the additional weight is rider dependent. That's all I'm saying. Doing this as a math experiment doesn't work.

Assume on your best day and lightest bike that you are red-lining keeping up with the group on a climb. Then you add lets say 5 pounds by riding your swampy, soft gravel bike. You will go beyond red-lining to hold on, and then you will blow. You will be catching your breath, slowing down so your heart doesn't explode and pondering a call to Uber. You will not be off by some linear amount of time produced by a mathematical formula. You will be stopping for a picnic.

Sure, that 2% difference could push your over some hard and fast limit.
If, that is, you were actually at a hard and fast limit. If you didn't
get a swirl of tailwind that the lead rider missed. If you didn't get
get angry, or grit your teeth harder, or otherwise get a few drops of
adrenaline. If you didn't get a little better run at the start of the
hill. If you hadn't lost some body fat since the last ride. If you
weren't riding behind a big guy with a bigger draft. If you didn't hit a
little patch of road that was smoother than what the other guys happened
to hit. If ...

(BTW, on the day described above, I did think I was at my limit. I
actually lay down in the road while others in the group fixed a guys flat.)

I just don't think the magic is all that consistent, given the dozen
other factors that affect making it up a particular hill. I'm not saying
weight doesn't make a difference. But I think for small weight changes,
it's almost never a critical difference - except maybe psychologically.

And I notice you chose five pounds for your example, which gives a bit
over 2% more climbing speed. I also ran numbers for two pounds, yielding
1% difference in climbing speed. Would you agree that the two pounds,
one percent is negligible?

How about one pound? Half a pound? 100 grams? Where, exactly, does the
magic kick in?

--
- Frank Krygowski

On Wednesday, June 19, 2019 at 10:10:24 PM UTC-5, Sir Ridesalot wrote:

Oh, another thing. I have another bicycle with 9 cogs on it. I have it set up with 7 fairly close cogs and 2 bailout/wind/steep hills cogs. It gives me the best of a 7 cogs setup plus those two bailout gears.


Back in about 1985 I (actually my oldest brother) ordered a custom 7 speed Suntour freewheel from Bike Warehouse. Back then they offered custom freewheels. 13-14-15-16-17-20-24. Had a 52-40 crankset.

On 6/21/2019 12:48 AM, wrote:
On Wednesday, June 19, 2019 at 10:10:24 PM UTC-5, Sir Ridesalot wrote:

Oh, another thing. I have another bicycle with 9 cogs on it. I have it set up with 7 fairly close cogs and 2 bailout/wind/steep hills cogs. It gives me the best of a 7 cogs setup plus those two bailout gears.


Back in about 1985 I (actually my oldest brother) ordered a custom 7 speed Suntour freewheel from Bike Warehouse. Back then they offered custom freewheels. 13-14-15-16-17-20-24. Had a 52-40 crankset.

I did the same thing even earlier, in the 1970s, with five cogs. It was
before we had triple cranks, and I wanted to give my wife a big bailout
low gear. I remember the order-taker saying "Are you SURE those are the
cogs you want??"

ISTM that back then, Bike Warehouse (later Bike Nashbar) carried all
sorts of odd mechanical tidbits for bikes. That was before they figured
out that the real money is in clothing.


--
- Frank Krygowski

On Wednesday, June 19, 2019 at 9:49:48 AM UTC-7, duane wrote:
On 19/06/2019 10:25 a.m., jbeattie wrote:
On Tuesday, June 18, 2019 at 8:06:37 PM UTC-7, Frank Krygowski wrote:
On 6/18/2019 1:24 PM, jbeattie wrote:
On Tuesday, June 18, 2019 at 9:49:50 AM UTC-7, Frank Krygowski wrote:

For ordinary riding? No, most tiny improvements make no noticeable
difference. Even though we all know the near-magic power of red paint.

On Wednesday, June 19, 2019 at 1:27:59 PM UTC-7, sms wrote:
On 6/18/2019 10:24 AM, jbeattie wrote:

snip

What is a "tiny improvement"? The frame on my Emonda probably weighs less than the Columbus steel forks off my last custom racing bike. Those things were suitable for clubbing baby harp seals or home defense. Weight and stiffness do matter when climbing. If we're talking about aero bits, that's harder call -- except that dopes on aero bars riding in packs can result in a massive worsening of your riding experience. Wearing aero shoe covers may keep your feet warmer on chilly mornings, which might make you faster. It all adds up.

But it isn't just weight.

There is a significant performance difference between a well-made steel
racing frame and a carbon-fiber frame. The steel frame handles and
corners better and of course will last much longer. The lower weight of
the carbon-fiber frame, as well as all the other carbon-fiber pieces, is
the appeal to racers of carbon.

To non-racers, a decent carbon-fiber frame costs much less than a
well-made steel frame, though if you buy a complete bicycle the cost of
a high-end carbon-fiber equipped bicycle from a top-tier manufacturer
that provides a warranty, is comparable to that of a handmade steel or
titanium frame bicycle. And of course you could always use a
carbon-fiber form on a custom steel racing frame.

I really can't tell any difference between the Pinarello Stelvio, the Basso Loto (with Basso Tubing Concepts tubes) and the Colnago. There is no flex in the forks or enough flex in the frames to notice.

On Wednesday, June 19, 2019 at 1:52:30 PM UTC-7, Sir Ridesalot wrote:
On Wednesday, June 19, 2019 at 2:18:52 PM UTC-4, Frank Krygowski wrote:
On 6/19/2019 10:25 AM, jbeattie wrote:
On Tuesday, June 18, 2019 at 8:06:37 PM UTC-7, Frank Krygowski wrote:
On 6/18/2019 1:24 PM, jbeattie wrote:
On Tuesday, June 18, 2019 at 9:49:50 AM UTC-7, Frank Krygowski wrote:

For ordinary riding? No, most tiny improvements make no noticeable
difference. Even though we all know the near-magic power of red paint.


What is a "tiny improvement"? The frame on my Emonda probably weighs less than the Columbus steel forks off my last custom racing bike. Those things were suitable for clubbing baby harp seals or home defense. Weight and stiffness do matter when climbing. If we're talking about aero bits, that's harder call -- except that dopes on aero bars riding in packs can result in a massive worsening of your riding experience. Wearing aero shoe covers may keep your feet warmer on chilly mornings, which might make you faster. It all adds up.

Stiffness probably does not make a detectable difference, unless the
frame is so flexible that things are scraping. Remember the discussion
we had about the bike magazine's test of modern stiff CF frames vs.
older, heavier steel frames? The test riders gushed about how the
stiffness improved their climbing, but the math showed the speed
difference was precisely what would be predicted by the weight difference.

Weight matters when climbing. If getting to the top of the hill before
your buddy is really, really important, a lighter bike will help by
whatever the percent difference in total bike+rider weight. If a 160
pound rider changes his 20 pound bike for an 18 pound bike, he should be
about 1% faster up a steep hill. Whoopee!

Make that a 5lb weight difference. You need to borrow a well-fitting modern 15lb racing bike with an appropriate gear range and then do a long ride with lots of hills. It's not a subtle or imagined difference compared to a T1000 or old-school steel sport touring bike, particularly if you're trying to keep up with others.

Again, I'm not saying the weight doesn't make a difference! The
difference it makes on an uphill is the percentage difference in
bike+rider weight.

Does nobody remember the discussion a couple years ago where the
magazine article's data proved that? They put young racers on modern CF
bikes, then on 1980s steel racing bikes and timed them up long hills.
The speed difference was exactly what the weight difference predicted.

Think about changing to a bike that was five pounds lighter, but then
strapped a five pound weight around your waist. Hopefully people here
wouldn't think you'd still be way faster up the hills, right?

And again, the stiffness, the snappiness, the magical handling of a CF
bike made no difference at all in that comparison test. There were other
details the youngsters liked on the new bikes - as in "I was afraid to
take my hands off the hoods to shift" - but the speed difference was
apparently due to the weight.

If others think there's some other energy savings or power increase,
please explain it in engineering or scientific terms. Explain how it's
not magic.

--
- Frank Krygowski

Weight doesn't make a difference? News to me.

In 1984 I bought a MIELE BETA bicycle with Tange double-butted tubing and with a complete Shimano 600 groupset. A year or two later I bought a MIELE EQUIPE PRO with a Columbus SL frameset and with a complete Dura Ace groupset. Compared to the Beta the Equipe Pro climbed like a homesick angel, accelerated easier and in general took less energy to keep moving. I imagine that the difference a five to ten pounds lighter carbon fiber bicycle would be even more noticeable.

Cheers

Out the door weight of my Pinarello was one lb heavier than the Colnago. I sure as hell am not going to complain about one lb when all I have to do is empty the water bottle to get a lb back.