Carbon Fiber wheels and braking

On Sunday, September 27, 2020 at 10:21:33 AM UTC-7, Frank Krygowski wrote:
On 9/27/2020 12:54 PM, jbeattie wrote:
On Sunday, September 27, 2020 at 7:51:23 AM UTC-7, Frank Krygowski wrote:

Lou, I notice you get very testy any time I imply that the newest and
fastest and most advertised bike components may not be the best. Are you
on commission?

I doubt it. I think he is responding to your lack of any experience with the equipment you criticize. Meanwhile, Lou uses the stuff you criticize probably every day -- and also has years of using the stuff you use. Same here. I've used all your equipment. You haven't used mine, at least not to any significant degree. About to depart on CF/aluminum wheels (C35s), STI, 25mm tires -- one with a super poseur latex tube. I have CF bars that I really like. CF frame that I like a lot, too. It's quiet. Good cable management.. Nothing slaps around.
Liking something is affected by personal taste, priorities,
personalities, fashion, advertising and more. You're right that I can't
tell how much I'd like your CF bike without trying it. I certainly can't
tell how much _you_ would like your CF bike.

But the OP was asking about something much more concrete. He asked how
much difference carbon fiber wheels would make for his riding. One
doesn't have to use CF wheels to know the difference will be small. The
data is out there. Do you really disagree?

There's this thing called "Engineering." Engineers get trained in
performing tests, making measurements, _interpreting_ the resulting data
and applying judgment to produce good results.

Can you imagine a world where the engineering rules included "You
haven't actually run that particular industrial machine, so you can't
help decide whether it would be a good investment for our factory?"

You have personally not even seen in real life most of the stuff you're passing judgement on. You've performed no tests and you have calculated nothing since you have no real information about anything. It is ALL summed up in your "you didn't hit your head" posting.

Op zondag 27 september 2020 om 18:55:38 UTC+2 schreef :
On Sunday, September 27, 2020 at 11:51:20 AM UTC-5, wrote:
On Saturday, September 26, 2020 at 7:17:40 PM UTC-7, jbeattie wrote:

CF has its place, but not with rim brakes, IMO. You can get a fine aluminum wheel with most of the same characteristics at the same or even lower weight. I got the CF version of a mid-aero wheel, the Roval C38 -- because it had a better hub (cheap from my son, too), and I appreciate the stiffness. Its on a disc bike. My son traded away his CF rim-brake wheels and got a nice aluminum pair from his friend the Mavic rep. He has CF Rovals on his disc bikes.
The bike I just sold had ProLite Bracianno 40 mm aluminum wheels on them and I weighed them and they weighed a little less than the 50 mm carbon wheels. Now if you don't mind paying a fortune, you can get lighter carbon rims but when I bought those ProLites they cost me $250. I could not tell the difference in speed between the 40 mm ProLites and the 50 mm SuperTeam.
So now let me throw another monkey in the cage. What would latex tubes do for the ride? I have never tried them and are they worth it? It seems they are not a puncture resistance and loose air much faster?
Deacon Mark

Latex tubes are twice as expensive, they have less RR and they are more resistant to pinch flats than a butyl tube of the same weight. They loose air much faster, to an extent that you have to top them off every ride. Are they worth it? For most people not. I use them only on my as fast as possible aero bike.

Lou

On 9/27/2020 9:55 AM, Frank Krygowski wrote:
On 9/27/2020 7:41 AM, Mark Cleary wrote:
On Sunday, September 27, 2020 at 5:41:44 AM UTC-5,
wrote:
Op zondag 27 september 2020 om 01:37:53 UTC+2 schreef
Frank Krygowski:
On 9/26/2020 7:07 PM, Mark Cleary wrote:
On Saturday, September 26, 2020 at 4:00:26 PM UTC-5,
wrote:
On Saturday, September 26, 2020 at 1:26:29 PM UTC-7,
wrote:
I have always road basic aluminum clincher wheels.
Every once in awhile I get an urge to try CF wheels.
First of all is that a bad idea do they really do
much better. Then there is the issue of needing to
use the rim brake pad that is specific for carbon
fiber wheels.

The big question is if the braking performance is a
good a traditional AL rims? Anyone here running CF
wheels with CF braking tracks and what do you think?
In some ways maybe some aero wheels would be slightly
better for the flatlands where I live but maybe not
in the mountains of big hill rides. Would 38mm rims
blow me all around it sure seems like 50 and above
would.
Campagnolo makes some carbon fiber compatible brake
shoes that you can put in your high end brakes and
they brake almost as good as aluminum brakes and
standard shoes. Now that sort of makes me nervous
about the long term effects on carbon wheel brake
track. But the Chinese brake shoes have pretty bad
braking in comparison to aluminum. You get used to it
and don't much notice that you're braking earlier.

When buying deep aero wheels do NOT get "tubeless"
rims. Always get clincher only and not "bi" rims
(supposedly either tubeless or clincher compatible).
50 mm aero rims do give you a noticeably longer
coasting. So I guess the aero part is real. I'm now
playing around with tires again so that I don't get
flats. While Gatorskins have always protected me from
flats they do have a wooden ride. I like Michelin Pro
4's but you can't get them right now I suppose because
of the bike boom. So I am going to try Continental 4
Seasons which supposedly have as much flat protection
as Gatorskins with a better ride. We'll see about that
since I mounted a pair and they didn't seem that
different to me. They are on my Lemond which is
waiting for parts so I'll see.

Continental GP5000's wear really fast I suppose
because they have such great traction. But that
traction also had my bikes wandering all over the road
with the changes in camber and road surface. This was
bad enough that a section of road I used to descend at
about 30, I was slowing to 25 or less.

Vittoria Corsa 2+ are very nice tires but they, like 4
Seasons, are frightfully expensive. So presently I am
trying out the Michelin Power Endurance which is
supposed to be a balance of traction and wear.
Lou seems to be telling me they are ****ty braking and
therefore I need to simply get a disk brake bike right?
Does that solve the problem or am I complete nuts?
It's not clear to me what problem you're trying to solve.

Perhaps I'm wrong, but it sounds like most of your
riding is solo. If
so, are you trying to spend less time doing your
favorite routes? Carbon
rims won't help that very much - maybe a couple percent.
But why would
you want to do that?

If you're riding with friends and want to beat them to
the next
telephone pole or whatever, those rims may somewhat
increase the number
of such sprints you win. But it's a pretty expensive way
to say "Ha!
Take that!" to a friend.

If you're road racing at an amateur level, it's much the
same - an
expensive way to slightly increase your odds of winning
a water bottle.

If you're racing at a higher level than that, don't
worry about it. Just
ask your sponsor to buy them for you.

Don't worship technology for technology's sake. It's
just another form
of mammon.

--
- Frank Krygowski
Mark asked some questions he liked answers to. He don't
need a lecture from someone who has no experience with CF
rims.

Lou
Well I pretty much expected that the answer is no not
really any better. I am normally a solo rider and I do
appreciate brakes that work well. My rim brakes do a fine
job unless it is wet but even then they do work fine. I
was just getting a bit antsy. Personally I am thinking
about going to a disk brake road bike and have been
looking at Lynskey R300. Not the lightest animal on the
planet but nothing beats them in the price. Going to a
disk brake with a bit wider tires for me would a huge
change at least I think. I still run 23's but they are
fine on the roads I ride. The wider stuff would make some
roads easier. I guess what I appreciate more than anything
is a real smooth quiet riding bike it that makes sense. I
notice I road my Wilier GT last week 3 times and what
really was apparent was that it is noisier than the TI
Habanero by far. The CF seems to pick up the wind currents
and the cables make noise shifting. I went back to my
Habby and to me a pretty big difference.

It's refreshing to see someone mention benefits other than
speed. I agree about the joy of a quiet bike.

I wonder if you should just try some high quality 28mm
tires. They're likely to be more comfortable than your 23s
and there's a good chance they'll be faster, especially if
your roads have any significant roughness. Unlike most
so-called performance components, they might make a
difference you can actually feel.




You ought to test ride a belt drive bicycle when you are
able. No one notices chain noise until it isn't there!

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

On Sunday, September 27, 2020 at 10:38:39 AM UTC-7, Lou Holtman wrote:
Op zondag 27 september 2020 om 18:55:38 UTC+2 schreef :
On Sunday, September 27, 2020 at 11:51:20 AM UTC-5, wrote:
On Saturday, September 26, 2020 at 7:17:40 PM UTC-7, jbeattie wrote:

CF has its place, but not with rim brakes, IMO. You can get a fine aluminum wheel with most of the same characteristics at the same or even lower weight. I got the CF version of a mid-aero wheel, the Roval C38 -- because it had a better hub (cheap from my son, too), and I appreciate the stiffness. Its on a disc bike. My son traded away his CF rim-brake wheels and got a nice aluminum pair from his friend the Mavic rep. He has CF Rovals on his disc bikes.
The bike I just sold had ProLite Bracianno 40 mm aluminum wheels on them and I weighed them and they weighed a little less than the 50 mm carbon wheels. Now if you don't mind paying a fortune, you can get lighter carbon rims but when I bought those ProLites they cost me $250. I could not tell the difference in speed between the 40 mm ProLites and the 50 mm SuperTeam.
So now let me throw another monkey in the cage. What would latex tubes do for the ride? I have never tried them and are they worth it? It seems they are not a puncture resistance and loose air much faster?
Deacon Mark

Latex tubes are twice as expensive, they have less RR and they are more resistant to pinch flats than a butyl tube of the same weight. They loose air much faster, to an extent that you have to top them off every ride. Are they worth it? For most people not. I use them only on my as fast as possible aero bike.

Lou

In the COVID-19 tube shortage world, latex tubes on sale are a few bucks more than light butyl. I bought two recently and have on in the rear wheel I rode today. It's super-fast! I kept popping wheelies.

I was riding out on the Clackamas River. https://traveloregon.com/wp-content/...levich-012.jpg Not that part of it, but I really like the picture. I no longer have the gas to go that far up the river and back home, not this year. Anyway, no flats and a rock hit that might have flatted a butyl tube. Two guys passed me as I was daydreaming up a climb on the way home. I and my latex tube passed them back. I heard them crying "we have been vanquished by latex!" [wailing and sobbing heard offstage].

-- Jay Beattie.

On 9/27/2020 1:30 PM, Tom Kunich wrote:

Liking something is affected by personal taste, priorities,
personalities, fashion, advertising and more. You're right that I can't
tell how much I'd like your CF bike without trying it. I certainly can't
tell how much _you_ would like your CF bike.

But the OP was asking about something much more concrete. He asked how
much difference carbon fiber wheels would make for his riding. One
doesn't have to use CF wheels to know the difference will be small. The
data is out there. Do you really disagree?

There's this thing called "Engineering." Engineers get trained in
performing tests, making measurements, _interpreting_ the resulting data
and applying judgment to produce good results.

Can you imagine a world where the engineering rules included "You
haven't actually run that particular industrial machine, so you can't
help decide whether it would be a good investment for our factory?"

You have personally not even seen in real life most of the stuff you're passing judgement on.

Wrong yet again.

You've performed no tests and you have calculated nothing since you have no real information about anything.

I haven't personally tested carbon fiber wheels. But the data and
information is out there.

But since you are so experienced with so much excellent equipment, why
don't you give us an estimate of how much the deacon's average speed
will change by switching to CF wheels?

I realize I'm asking a guy who once claimed his wheels or tires actually
made the bike accelerate when coasting on flat ground. But I'd like to
see your estimate anyway.

--
- Frank Krygowski

On 9/27/2020 1:38 PM, Lou Holtman wrote:
Op zondag 27 september 2020 om 18:55:38 UTC+2 schreef :
On Sunday, September 27, 2020 at 11:51:20 AM UTC-5, wrote:
On Saturday, September 26, 2020 at 7:17:40 PM UTC-7, jbeattie wrote:

CF has its place, but not with rim brakes, IMO. You can get a fine aluminum wheel with most of the same characteristics at the same or even lower weight. I got the CF version of a mid-aero wheel, the Roval C38 -- because it had a better hub (cheap from my son, too), and I appreciate the stiffness. Its on a disc bike. My son traded away his CF rim-brake wheels and got a nice aluminum pair from his friend the Mavic rep. He has CF Rovals on his disc bikes.
The bike I just sold had ProLite Bracianno 40 mm aluminum wheels on them and I weighed them and they weighed a little less than the 50 mm carbon wheels. Now if you don't mind paying a fortune, you can get lighter carbon rims but when I bought those ProLites they cost me $250. I could not tell the difference in speed between the 40 mm ProLites and the 50 mm SuperTeam.
So now let me throw another monkey in the cage. What would latex tubes do for the ride? I have never tried them and are they worth it? It seems they are not a puncture resistance and loose air much faster?
Deacon Mark

Latex tubes are twice as expensive, they have less RR and they are more resistant to pinch flats than a butyl tube of the same weight. They loose air much faster, to an extent that you have to top them off every ride. Are they worth it? For most people not. I use them only on my as fast as possible aero bike.

Speaking of losing air: ISTM that I have to reinflate tires on certain
bikes much more often than others, despite roughly the same tire sizes.
For example, my fattest current tires, the utility three speed's 32mm
(actually 1 1/4") tires seem to need air more than any other.

I don't pay much attention when I buy an inner tube. I just get the
right size of whatever butyl tube brand is on the shelf. It makes me
wonder if there are significant differences in permeability based on
composition, etc. as opposed to thickness. Or if there could be.

--
- Frank Krygowski

On Sunday, September 27, 2020 at 10:21:33 AM UTC-7, Frank Krygowski wrote:
On 9/27/2020 12:54 PM, jbeattie wrote:
On Sunday, September 27, 2020 at 7:51:23 AM UTC-7, Frank Krygowski wrote:

Lou, I notice you get very testy any time I imply that the newest and
fastest and most advertised bike components may not be the best. Are you
on commission?

I doubt it. I think he is responding to your lack of any experience with the equipment you criticize. Meanwhile, Lou uses the stuff you criticize probably every day -- and also has years of using the stuff you use. Same here. I've used all your equipment. You haven't used mine, at least not to any significant degree. About to depart on CF/aluminum wheels (C35s), STI, 25mm tires -- one with a super poseur latex tube. I have CF bars that I really like. CF frame that I like a lot, too. It's quiet. Good cable management. Nothing slaps around.

Liking something is affected by personal taste, priorities,
personalities, fashion, advertising and more. You're right that I can't
tell how much I'd like your CF bike without trying it. I certainly can't
tell how much _you_ would like your CF bike.

But the OP was asking about something much more concrete. He asked how
much difference carbon fiber wheels would make for his riding. One
doesn't have to use CF wheels to know the difference will be small. The
data is out there. Do you really disagree?

There's this thing called "Engineering." Engineers get trained in
performing tests, making measurements, _interpreting_ the resulting data
and applying judgment to produce good results.

Can you imagine a world where the engineering rules included "You
haven't actually run that particular industrial machine, so you can't
help decide whether it would be a good investment for our factory?"

Yes. This is why pilots are trained in simulators for various aircraft. They all fly differently -- even planes with very similar specs. Same goes with bikes. They're not just a collection of results from some test frame.

Brake hood shape, bar bend, saddle design, shift lever location and operation, brake modulation, tire feel (yes feel), pedal and shoe systems all affect the way a bike rides -- and those things are not capable of easy expression in engineering terms. A modern CF or hydroformed aluminum racing bike -- which you do not own or ride -- is a lot different that a steel racing bike of yore, and to me, a lot more fun to ride. Its not just "marketing" as you frequently claim.

I would never take advice on a product from someone with no experience either owning it or maintaining/warrantying it. I would want to talk to someone who has used the product in an environment similar to mine. Riding with people who are in the industry gives me that opportunity, and that's why I never bought a CF rim-brake wheel. Too many hills and too much rain for a CF rim brake wheel.

-- Jay Beattie.

On 9/27/2020 5:21 PM, jbeattie wrote:
On Sunday, September 27, 2020 at 10:21:33 AM UTC-7, Frank Krygowski wrote:
On 9/27/2020 12:54 PM, jbeattie wrote:
On Sunday, September 27, 2020 at 7:51:23 AM UTC-7, Frank Krygowski wrote:

Lou, I notice you get very testy any time I imply that the newest and
fastest and most advertised bike components may not be the best. Are you
on commission?

I doubt it. I think he is responding to your lack of any experience with the equipment you criticize. Meanwhile, Lou uses the stuff you criticize probably every day -- and also has years of using the stuff you use. Same here. I've used all your equipment. You haven't used mine, at least not to any significant degree. About to depart on CF/aluminum wheels (C35s), STI, 25mm tires -- one with a super poseur latex tube. I have CF bars that I really like. CF frame that I like a lot, too. It's quiet. Good cable management. Nothing slaps around.

Liking something is affected by personal taste, priorities,
personalities, fashion, advertising and more. You're right that I can't
tell how much I'd like your CF bike without trying it. I certainly can't
tell how much _you_ would like your CF bike.

But the OP was asking about something much more concrete. He asked how
much difference carbon fiber wheels would make for his riding. One
doesn't have to use CF wheels to know the difference will be small. The
data is out there. Do you really disagree?

There's this thing called "Engineering." Engineers get trained in
performing tests, making measurements, _interpreting_ the resulting data
and applying judgment to produce good results.

Can you imagine a world where the engineering rules included "You
haven't actually run that particular industrial machine, so you can't
help decide whether it would be a good investment for our factory?"

Yes. This is why pilots are trained in simulators for various aircraft. They all fly differently -- even planes with very similar specs. Same goes with bikes. They're not just a collection of results from some test frame.

Brake hood shape, bar bend, saddle design, shift lever location and operation, brake modulation, tire feel (yes feel), pedal and shoe systems all affect the way a bike rides -- and those things are not capable of easy expression in engineering terms. A modern CF or hydroformed aluminum racing bike -- which you do not own or ride -- is a lot different that a steel racing bike of yore, and to me, a lot more fun to ride. Its not just "marketing" as you frequently claim.

I would never take advice on a product from someone with no experience either owning it or maintaining/warrantying it. I would want to talk to someone who has used the product in an environment similar to mine. Riding with people who are in the industry gives me that opportunity, and that's why I never bought a CF rim-brake wheel. Too many hills and too much rain for a CF rim brake wheel.

Again, your argument is focusing on "feel" AKA "the way a bike rides."
I'm not claiming all bikes "feel" the same. I'm not claiming you,
personally, don't enjoy some bikes more than others. But again,
enjoyment and appreciation of "feel" is a very individual thing.

Mark didn't seem to be asking about "feel." The impression that I got
was that he wanted to know if carbon wheels would make him significantly
faster. That _is_ an engineering question. The data's out there.

The answer is, any speed increase will be negligible unless you're in a
race. And even then, it's not likely to help very much.

I'll admit, I haven't dug for the data during this conversation. I'm
curious whether, for a typical solo recreational rider, the aero
advantage of carbon wheels can be negated by a floppy jersey.

--
- Frank Krygowski

On Sun, 27 Sep 2020 13:27:21 -0400, Frank Krygowski
wrote:

On 9/27/2020 10:58 AM, Lou Holtman wrote:
Op zondag 27 september 2020 om 13:41:48 UTC+2 schreef :
On Sunday, September 27, 2020 at 5:41:44 AM UTC-5, wrote:
Op zondag 27 september 2020 om 01:37:53 UTC+2 schreef Frank Krygowski:
On 9/26/2020 7:07 PM, Mark Cleary wrote:
On Saturday, September 26, 2020 at 4:00:26 PM UTC-5, wrote:
On Saturday, September 26, 2020 at 1:26:29 PM UTC-7, wrote:
I have always road basic aluminum clincher wheels. Every once in awhile I get an urge to try CF wheels. First of all is that a bad idea do they really do much better. Then there is the issue of needing to use the rim brake pad that is specific for carbon fiber wheels.

The big question is if the braking performance is a good a traditional AL rims? Anyone here running CF wheels with CF braking tracks and what do you think? In some ways maybe some aero wheels would be slightly better for the flatlands where I live but maybe not in the mountains of big hill rides. Would 38mm rims blow me all around it sure seems like 50 and above would.
Campagnolo makes some carbon fiber compatible brake shoes that you can put in your high end brakes and they brake almost as good as aluminum brakes and standard shoes. Now that sort of makes me nervous about the long term effects on carbon wheel brake track. But the Chinese brake shoes have pretty bad braking in comparison to aluminum. You get used to it and don't much notice that you're braking earlier.

When buying deep aero wheels do NOT get "tubeless" rims. Always get clincher only and not "bi" rims (supposedly either tubeless or clincher compatible). 50 mm aero rims do give you a noticeably longer coasting. So I guess the aero part is real. I'm now playing around with tires again so that I don't get flats. While Gatorskins have always protected me from flats they do have a wooden ride. I like Michelin Pro 4's but you can't get them right now I suppose because of the bike boom. So I am going to try Continental 4 Seasons which supposedly have as much flat protection as Gatorskins with a better ride. We'll see about that since I mounted a pair and they didn't seem that different to me. They are on my Lemond which is waiting for parts so I'll see.

Continental GP5000's wear really fast I suppose because they have such great traction. But that traction also had my bikes wandering all over the road with the changes in camber and road surface. This was bad enough that a section of road I used to descend at about 30, I was slowing to 25 or less.

Vittoria Corsa 2+ are very nice tires but they, like 4 Seasons, are frightfully expensive. So presently I am trying out the Michelin Power Endurance which is supposed to be a balance of traction and wear.
Lou seems to be telling me they are ****ty braking and therefore I need to simply get a disk brake bike right? Does that solve the problem or am I complete nuts?
It's not clear to me what problem you're trying to solve.

Perhaps I'm wrong, but it sounds like most of your riding is solo. If
so, are you trying to spend less time doing your favorite routes? Carbon
rims won't help that very much - maybe a couple percent. But why would
you want to do that?

If you're riding with friends and want to beat them to the next
telephone pole or whatever, those rims may somewhat increase the number
of such sprints you win. But it's a pretty expensive way to say "Ha!
Take that!" to a friend.

If you're road racing at an amateur level, it's much the same - an
expensive way to slightly increase your odds of winning a water bottle.

If you're racing at a higher level than that, don't worry about it. Just
ask your sponsor to buy them for you.

Don't worship technology for technology's sake. It's just another form
of mammon.

--
- Frank Krygowski
Mark asked some questions he liked answers to. He don't need a lecture from someone who has no experience with CF rims.

Lou
Well I pretty much expected that the answer is no not really any better. I am normally a solo rider and I do appreciate brakes that work well. My rim brakes do a fine job unless it is wet but even then they do work fine. I was just getting a bit antsy. Personally I am thinking about going to a disk brake road bike and have been looking at Lynskey R300. Not the lightest animal on the planet but nothing beats them in the price. Going to a disk brake with a bit wider tires for me would a huge change at least I think. I still run 23's but they are fine on the roads I ride. The wider stuff would make some roads easier. I guess what I appreciate more than anything is a real smooth quiet riding bike it that makes sense. I notice I road my Wilier GT last week 3 times and what really was apparent was that it is noisier than the TI Habanero by far. The CF seems to pick up the wind currents and the cables make noise shifting. I went back to my Habby and to me a pretty big difference.

Deacon Mark

You are right that a heavier Ti frame with smaller tubes is less of a resonance box as a CF frame with large aero tubes and is definitely a lot quieter. Be aware that high volume CF rims have the same effect, not as much as a CF frame but still. It was wet and windy today so I took my Ti disc gravel bike with 45 mm CF rims and 32 mm Continental GP5000 tires. It was an excellent ride, quiet, reasonable fast and with consistent braking. Concerning wider tires I found this article interesting. Confirms my experience. Low RR and comfort? You can pick one.

https://www.bicyclerollingresistance...000-comparison

There was a lot of interesting detail in that test and article. Their
diamond plate roller is certainly an improvement over a smooth one.

But they are still not modeling the energy losses from vibrating the
rider and bike frame. I suspect the differences between tire sizes would
be greater if that could somehow be accurately measured.

But I wonder whether rolling resistance is applicable to real life.
After all the rolling resistance of a, oh say 28mm tire, must vary
whether supporting a 120 lb rider or a 200 lb rider.

Perhaps the way to low rolling resistance is "loose weight"!
--
Cheers,

John B.

Frank Krygowski wrote:
On 9/27/2020 1:38 PM, Lou Holtman wrote:
Op zondag 27 september 2020 om 18:55:38 UTC+2 schreef :
On Sunday, September 27, 2020 at 11:51:20 AM UTC-5, wrote:
On Saturday, September 26, 2020 at 7:17:40 PM UTC-7, jbeattie wrote:

CF has its place, but not with rim brakes, IMO. You can get a fine
aluminum wheel with most of the same characteristics at the same or
even lower weight. I got the CF version of a mid-aero wheel, the
Roval C38 -- because it had a better hub (cheap from my son, too),
and I appreciate the stiffness. Its on a disc bike. My son traded
away his CF rim-brake wheels and got a nice aluminum pair from his
friend the Mavic rep. He has CF Rovals on his disc bikes.
The bike I just sold had ProLite Bracianno 40 mm aluminum wheels on
them and I weighed them and they weighed a little less than the 50 mm
carbon wheels. Now if you don't mind paying a fortune, you can get
lighter carbon rims but when I bought those ProLites they cost me
$250. I could not tell the difference in speed between the 40 mm
ProLites and the 50 mm SuperTeam.
So now let me throw another monkey in the cage. What would latex tubes
do for the ride? I have never tried them and are they worth it? It
seems they are not a puncture resistance and loose air much faster?
Deacon Mark

Latex tubes are twice as expensive, they have less RR and they are more
resistant to pinch flats than a butyl tube of the same weight. They
loose air much faster, to an extent that you have to top them off every
ride. Are they worth it? For most people not. I use them only on my as
fast as possible aero bike.

Speaking of losing air: ISTM that I have to reinflate tires on certain
bikes much more often than others, despite roughly the same tire sizes.
For example, my fattest current tires, the utility three speed's 32mm
(actually 1 1/4") tires seem to need air more than any other.

I don't pay much attention when I buy an inner tube. I just get the
right size of whatever butyl tube brand is on the shelf. It makes me
wonder if there are significant differences in permeability based on
composition, etc. as opposed to thickness. Or if there could be.


I tend to buy the largest tube that will fit inside the tire without
wrinkling on the assumption that minimal stretching of the tube as it’s
inflated will result in a thicker, more puncture resistant tube. Also, if
it is punctured, the tube that’s stretched less should leak less air
through the hole. But, the larger the tire diameter, the less it should
leak, for two reasons - the ratio of volume to surface area is larger for a
skinny tire, and larger tires tend to be inflated to lower pressures.