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  #21  
Old January 11th 17, 04:19 PM posted to rec.bicycles.tech
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On Tuesday, January 10, 2017 at 5:50:30 PM UTC-8, James wrote:
On 11/01/17 10:06, wrote:


What - are you the punk kid of the group?


Nah, you're just an old geezer, Tom.

Your bike isn't geared
particularly low. These days I'm seeing more and more compacts with a
34 on the back. And I thought my 39-28 was cheating after the 39-25.
But I do carry a triple now do that anything over 14% I use the 30-25
or so. But there are VERY few extended climbs over 12% around here.


My 8.4kg bike (includes cages and pedals) carries me up 20% grades with
a 39x23 low gear.


And eight years ago before my carbon fiber fork failure dumped me on my head I was climbing on steel bikes up 18% grades with a 42-23. Mind you I wasn't fast but I still don't see much sense in that. If you're a racer, fine. But if you aren't trying to go faster than someone else is pure ego.
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  #22  
Old January 11th 17, 04:30 PM posted to rec.bicycles.tech
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On Tuesday, January 10, 2017 at 5:56:41 PM UTC-8, James wrote:
On 11/01/17 08:11, wrote:
On Tuesday, January 10, 2017 at 6:48:20 AM UTC-8,
wrote:
A friend who speaks Italian spoke with a bike builder in Italy who
spoke to Ernesto Colnago. He verified that the problem with Carbon
Fiber aside from possible manufacturing defects is that the resins
grow more and more brittle with age. After two years or so they can
grow so brittle that the ultra-lights can fail at any second. This
is why Colnago will only give two year warranties and why they
build their "light" bikes considerably heavier than other
manufacturers.

Have a good ride on your CF when you can get the same weight with
an aluminum frame.


I don't know how many of you besides Joerge make a habit of hard
climbs. But light bikes do NOT make hard climbs much easier. In fact
they add a lot of problems. Once the grade gets up to 18% you can't
use low gears because on the light bikes it will lift the front wheel
off of the ground. The bike will then pivot around the rear wheel and
if you're ready for that you can lay the bike over before it turns
down hill.


That's funny. The difference between a light bike and a "normal" road
bike might be a 1-2kg. Compared to the body weight of the rider at
70-80kg, this is nothing - and it is a distributed weigh loss over the
entire bike, not just the front end.


James, you are FAR out of it. A "light" bike now is under six kg and possibly down to 5 1/2.

Experienced cyclists move their body weight forward to keep the front
wheel on the ground and maintain traction with very low gears. MTB
riders have been doing it for decades.


Modern bicycle design with short wheelbases and long top tubes do not allow you to shift your center of gravity forward unless you can stand up. And you can't stand on the pedals on steep hills where you have to pedal circles.


The way professional climbers get away with this is that they use
LARGE gears. Then you don't have the leverage to lift the front
wheel.


BS.


George Hincapie won a mountain stage of the Tour even though he is a sprinter. His gear was a 23 and that was the lowest gear of the group going over the top.
  #23  
Old January 11th 17, 04:36 PM posted to rec.bicycles.tech
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On Tuesday, January 10, 2017 at 5:59:05 PM UTC-8, James wrote:
On 11/01/17 01:48, wrote:
A friend who speaks Italian spoke with a bike builder in Italy who
spoke to Ernesto Colnago. He verified that the problem with Carbon
Fiber aside from possible manufacturing defects is that the resins
grow more and more brittle with age. After two years or so they can
grow so brittle that the ultra-lights can fail at any second. This is
why Colnago will only give two year warranties and why they build
their "light" bikes considerably heavier than other manufacturers.

Have a good ride on your CF when you can get the same weight with an
aluminum frame.


I don't believe age is what causes embrittlement in CFRP, but exposure
to UV light and contaminants that may attack the polymer probably does.


James, you don't HAVE to believe it. All it means is that the curing agents in the resins have to have a fairly large amount over the ideal in order to harden in the time necessary to use on a production line. And since there is more curing agent than resin it will continue to cure for a VERY long time afterwards. Some chemists believe that the curing agent is never "used up" but rather is always present and hence will continue to harden the resin forever. But experience has shown that after it reaches a certain point the hardening slows a great deal.

But that SAME experience is showing that this hardening continues into embrittlement after long enough. There are NO OTHER resins that offer the characteristics of epoxy or polyesters.

Though you're free to invent a new chemistry.
  #24  
Old January 11th 17, 04:38 PM posted to rec.bicycles.tech
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On Tuesday, January 10, 2017 at 7:13:36 PM UTC-8, John B. wrote:
On Wed, 11 Jan 2017 12:59:03 +1100, James
wrote:

On 11/01/17 01:48, wrote:
A friend who speaks Italian spoke with a bike builder in Italy who
spoke to Ernesto Colnago. He verified that the problem with Carbon
Fiber aside from possible manufacturing defects is that the resins
grow more and more brittle with age. After two years or so they can
grow so brittle that the ultra-lights can fail at any second. This is
why Colnago will only give two year warranties and why they build
their "light" bikes considerably heavier than other manufacturers.

Have a good ride on your CF when you can get the same weight with an
aluminum frame.


I don't believe age is what causes embrittlement in CFRP, but exposure
to UV light and contaminants that may attack the polymer probably does.


UV causes deterioration of both epoxy and polyester resins so some
sort of UV protection is required, and incorporated, into carbon fiber
bicycles. This could be almost anything from gel-coat to a paint job.


Yes, John, but most failures of these CF parts are not on the surface where the UV is causing deterioration of the very thin surface layer. And in the painted bikes it won't even penetrate the paint.
  #25  
Old January 11th 17, 04:41 PM posted to rec.bicycles.tech
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On Tuesday, January 10, 2017 at 8:04:57 PM UTC-8, jbeattie wrote:
On Tuesday, January 10, 2017 at 7:28:41 PM UTC-8, Frank Krygowski wrote:
On 1/10/2017 4:11 PM, wrote:
But light bikes do NOT make hard climbs much easier. In fact they add a lot of problems. Once the grade gets up to 18% you can't use low gears because on the light bikes it will lift the front wheel off of the ground. The bike will then pivot around the rear wheel and if you're ready for that you can lay the bike over before it turns down hill.

The way professional climbers get away with this is that they use LARGE gears. Then you don't have the leverage to lift the front wheel.


I think you need to draw a free body diagram of the forces involved.


Sure, you can pop a wheelie on a steep grade if you put too much weight over the rear wheel on a short wheelbase bike in a super-low gear -- but you can do that with a steel bike, too. That's why you move your weight forward a little -- but not so much that you lose rear traction.

Professional climbers do not use LARGE gears. Post-Lance, they spin. My son was on the crew for the Tour of Utah and was surprised that a lot of domestic and Euro pros were using low gears. Here's a photo that he took:
http://tinyurl.com/hpztj3o That ride has some staggering climbs with 20% grades.


Jay, take out a CX bike with super low gears on a mountain bike course with extremely steep sections just one time and you'll see what I'm talking about. Then use this same bike on steep asphalt sections and it is so plain that you can't miss it.
  #26  
Old January 11th 17, 04:50 PM posted to rec.bicycles.tech
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On Wednesday, January 11, 2017 at 12:20:16 AM UTC-8, wrote:
On Wednesday, January 11, 2017 at 12:06:30 AM UTC+1, wrote:
On Tuesday, January 10, 2017 at 2:26:04 PM UTC-8, wrote:
On Tuesday, January 10, 2017 at 9:56:04 PM UTC+1, wrote:
On Tuesday, January 10, 2017 at 11:33:43 AM UTC-8, wrote:
On Tuesday, January 10, 2017 at 3:48:20 PM UTC+1, wrote:
A friend who speaks Italian spoke with a bike builder in Italy who spoke to Ernesto Colnago. He verified that the problem with Carbon Fiber aside from possible manufacturing defects is that the resins grow more and more brittle with age. After two years or so they can grow so brittle that the ultra-lights can fail at any second. This is why Colnago will only give two year warranties and why they build their "light" bikes considerably heavier than other manufacturers.

Have a good ride on your CF when you can get the same weight with an aluminum frame.

Colnago doesn't have the know how to build light CF bikes that last and/or stiff enough so the answer of Ernesto doesn't surprise me.
Something like Kodak that didn't know anything about digital camera's.

Show me an aluminum frame of 850 grams. Any frame lighter than 1300 gram I prefer the CF one. YMMV.

Lou

Lou - what frame of ANY sort weighs a lb and three quarters?

My CF frame (850 gr doesn't include fork). Last 2 seasons I rode this bike

https://picasaweb.google.com/1010765...CPnlxYTUi5_zfA

Best bike I ever had. I replaced the seat post with a Thomson Masterpiece because the CF Ritchey post kept creaking because of a design flaw.

I saw and Eddy Merckx aluminum frame and fork that weighed 4 lbs. On steel bike maker tells me that he is making 16 lb bikes all up.

What would YOU use a 12 lb all up bike for?

Climbing and descending famous mountain passes in Europe for instance this year (a selection):

http://lh3.googleusercontent.com/-zt...o/IMG_1499.JPG

http://lh3.googleusercontent.com/-wP...o/IMG_1493.JPG

http://lh3.googleusercontent.com/-fq...o/IMG_1495.JPG


Lou


What - are you the punk kid of the group? Your bike isn't geared particularly low. These days I'm seeing more and more compacts with a 34 on the back. And I thought my 39-28 was cheating after the 39-25. But I do carry a triple now do that anything over 14% I use the 30-25 or so. But there are VERY few extended climbs over 12% around here.


When I go on a trip like that I use a 12-29 cassette which gives me a lowest gear of 34-29. That is enough for me for longer stretches (couple of km) up to 10-12%.


While the Gavia and the Umbrail aren't particularly high they are known for their difficulty because of the speed of the climbs by the pro peloton..

The first one I recognize but can't place it.


It is the Stelvio looking towards Bormio.


I am stuck with a 29 as well I actually am used to the 28 on my 9 speeds but I have 10 speeds on the Eddy Merckx. The 27 is just a tad too high with the 39 and the 29 bothers me because it slows your progress down and you work a little harder because you take longer to get over the climbs.

After I tried a compact I just couldn't take how much longer I was on climbs. And the I prefer to be in the lowest gear so that I know I don't have any alternative than the triple which I only use when I'm getting back in shape after a winter like this when you go for months without any significant riding.

Unless you're Jay and don't mind riding on roadways with cars turning upside down and driving 20 mph above the speed limit without a single cop doing a thing about it.
  #27  
Old January 11th 17, 04:51 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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On 1/11/2017 11:19 AM, wrote:

And eight years ago before my carbon fiber fork failure dumped me on my head I was climbing on steel bikes up 18% grades with a 42-23. Mind you I wasn't fast but I still don't see much sense in that. If you're a racer, fine. But if you aren't trying to go faster than someone else is pure ego.


Sometimes it's not ego; it's training.

FWIW, my "regular" (non-granny) gears are lower than that, and most of
my bikes have triple cranks with "granny" chainrings besides, for use
when absolutely necessary.

But my philosophy has always been to stay out of the little granny ring
during regular riding, no matter how tough the hill. I've always
figured that builds up the quadriceps muscles. And stuff I've read
recently confirmed that the only way to build muscle strength is to
occasionally stress the muscles until they can barely pull one more time.

Anyway, that's what I did in normal riding. Then if I were doing a
super-long ride (over 100 miles), or doing an extended tour especially
with a camping load, I'd use the opposite strategy. I'd drop into as
low a gear as was reasonable at every opportunity. That way I didn't
burn up the reserve of strength I'd built up from the hard pushing.

The combination of those strategies seemed to work for me.

--
- Frank Krygowski
  #28  
Old January 11th 17, 04:58 PM posted to rec.bicycles.tech
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On Wednesday, January 11, 2017 at 12:22:57 AM UTC-8, wrote:
On Wednesday, January 11, 2017 at 5:04:57 AM UTC+1, jbeattie wrote:
On Tuesday, January 10, 2017 at 7:28:41 PM UTC-8, Frank Krygowski wrote:
On 1/10/2017 4:11 PM, wrote:
But light bikes do NOT make hard climbs much easier. In fact they add a lot of problems. Once the grade gets up to 18% you can't use low gears because on the light bikes it will lift the front wheel off of the ground.. The bike will then pivot around the rear wheel and if you're ready for that you can lay the bike over before it turns down hill.

The way professional climbers get away with this is that they use LARGE gears. Then you don't have the leverage to lift the front wheel.

I think you need to draw a free body diagram of the forces involved.


Sure, you can pop a wheelie on a steep grade if you put too much weight over the rear wheel on a short wheelbase bike in a super-low gear -- but you can do that with a steel bike, too. That's why you move your weight forward a little -- but not so much that you lose rear traction.

Professional climbers do not use LARGE gears. Post-Lance, they spin. My son was on the crew for the Tour of Utah and was surprised that a lot of domestic and Euro pros were using low gears. Here's a photo that he took:
http://tinyurl.com/hpztj3o That ride has some staggering climbs with 20% grades.

-- Jay Beattie.


Pro riders use 34-28 regurarly on 14% grades and steeper.

Lou


When Hincapie won that mountain stage in the Tour they said his gearing was 39-23 and that the other three guys that were with him were riding larger gears.

I watched that German that won that mountain stage a couple of years ago and he was riding a HUGE gear. At the end he was barely moving.

You can't go fast in a low gear - spinning only gives you so much. At 90 rpm you get about 14 mph on a 42/21. On a 34/34 you would have to spin at 180 rpm. Try that for any length of time.
  #29  
Old January 11th 17, 05:02 PM posted to rec.bicycles.tech
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On Wednesday, January 11, 2017 at 8:59:00 AM UTC-8, wrote:
On Wednesday, January 11, 2017 at 12:22:57 AM UTC-8, wrote:
On Wednesday, January 11, 2017 at 5:04:57 AM UTC+1, jbeattie wrote:
On Tuesday, January 10, 2017 at 7:28:41 PM UTC-8, Frank Krygowski wrote:
On 1/10/2017 4:11 PM, wrote:
But light bikes do NOT make hard climbs much easier. In fact they add a lot of problems. Once the grade gets up to 18% you can't use low gears because on the light bikes it will lift the front wheel off of the ground. The bike will then pivot around the rear wheel and if you're ready for that you can lay the bike over before it turns down hill.

The way professional climbers get away with this is that they use LARGE gears. Then you don't have the leverage to lift the front wheel.

I think you need to draw a free body diagram of the forces involved..

Sure, you can pop a wheelie on a steep grade if you put too much weight over the rear wheel on a short wheelbase bike in a super-low gear -- but you can do that with a steel bike, too. That's why you move your weight forward a little -- but not so much that you lose rear traction.

Professional climbers do not use LARGE gears. Post-Lance, they spin. My son was on the crew for the Tour of Utah and was surprised that a lot of domestic and Euro pros were using low gears. Here's a photo that he took:
http://tinyurl.com/hpztj3o That ride has some staggering climbs with 20% grades.

-- Jay Beattie.


Pro riders use 34-28 regurarly on 14% grades and steeper.

Lou


When Hincapie won that mountain stage in the Tour they said his gearing was 39-23 and that the other three guys that were with him were riding larger gears.

I watched that German that won that mountain stage a couple of years ago and he was riding a HUGE gear. At the end he was barely moving.

You can't go fast in a low gear - spinning only gives you so much. At 90 rpm you get about 14 mph on a 42/21. On a 34/34 you would have to spin at 180 rpm. Try that for any length of time.


I misread Lou - the number isn't 180 rpm but 150. But TRY on a long climb.
  #30  
Old January 11th 17, 05:57 PM posted to rec.bicycles.tech
JBeattie
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Default New Carbon Fiber Information

On Wednesday, January 11, 2017 at 8:41:13 AM UTC-8, wrote:
On Tuesday, January 10, 2017 at 8:04:57 PM UTC-8, jbeattie wrote:
On Tuesday, January 10, 2017 at 7:28:41 PM UTC-8, Frank Krygowski wrote:
On 1/10/2017 4:11 PM, wrote:
But light bikes do NOT make hard climbs much easier. In fact they add a lot of problems. Once the grade gets up to 18% you can't use low gears because on the light bikes it will lift the front wheel off of the ground.. The bike will then pivot around the rear wheel and if you're ready for that you can lay the bike over before it turns down hill.

The way professional climbers get away with this is that they use LARGE gears. Then you don't have the leverage to lift the front wheel.

I think you need to draw a free body diagram of the forces involved.


Sure, you can pop a wheelie on a steep grade if you put too much weight over the rear wheel on a short wheelbase bike in a super-low gear -- but you can do that with a steel bike, too. That's why you move your weight forward a little -- but not so much that you lose rear traction.

Professional climbers do not use LARGE gears. Post-Lance, they spin. My son was on the crew for the Tour of Utah and was surprised that a lot of domestic and Euro pros were using low gears. Here's a photo that he took:
http://tinyurl.com/hpztj3o That ride has some staggering climbs with 20% grades.


Jay, take out a CX bike with super low gears on a mountain bike course with extremely steep sections just one time and you'll see what I'm talking about. Then use this same bike on steep asphalt sections and it is so plain that you can't miss it.


You have to shift your weight to avoid the wheelie effect. I commute on a CX bike and ride steep hills every day on asphalt and dirt -- including a dirt trail that goes straight up next to a set of steps. It is over 30%. I ride that on a 34/26 -- which is my low gear on that bike, but I do it out of the saddle, fairly centered until I bog down and lose traction (I also encounter a barrier). I ride steep asphalt in the same gears on the CX bike, but usually out of the saddle for the steepest parts. I have a Roubaix that has a 34/28, and it will wheelie if I don't move forward a little. I'm not disputing that you can get the "light front end" wobble or wheelie. You just have to change your riding position. BTW, I sometimes ride the steepest street in America and perhaps the world -- which is not too far from my house. http://offbeatoregon.com/H1010b_oreg...st-street.html These dudes are preparing for the epic climb: https://www.flickr..com/photos/gabri...995/?ytcheck=1

-- Jay Beattie.
 




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