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Bike Weight

Old 06-17-10, 10:42 PM
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heh, I ride a 26 year old steel touring bike.

What is this weight thing of which you speak?

In all honesty I've considered getting a lighter, more responsive bike. Most likely a Trek Pilot 2.1 (rode my dads, and loved it.) but the truth is I intend to use my bike to ride to work. That means a bag full of clothes, and another bag full of laptop on the back. I also will be pulling my daughter around in a trailer once she's big enough for me to find a helmet that fits her. (She'll be one on fathers day ) Even if I rode a full titanium race bike, with carbon everywhere, and the lightest of all components. I still can't use it for the things I'd like it to do

I'm still tempted to buy that Pilot though Wonder what the Roadies I pass on my way into work would think when they see it equipped with fenders.
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Old 06-18-10, 06:25 AM
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Originally Posted by Mr. Beanz
Hardly true at all! Think about the physical conditioning benefits gained during the training to lose those 10 lbs. If I lose 10 lbs, it takes some serious hill riding to accomplish that. If I sat on my butt, bought a bike 10 lbs ligther, no way will I be just as fit as I would if I had trained my butt of to lose the 10 lbs.
Couldn't agree more.
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Old 06-18-10, 07:51 AM
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Some decade ago, a bike science group did a test. They put a black water bottle on the test bike, sometimes it was filled with lead and sometimes it was filled with air. The rider was not permitted to lift the bike or bottle. At the end of the tests, not much difference between air and lead. The only difference was the expected hill climbing horsepower to weight factor.
When weight matters, it's total weight not wheel weight, bike weight, or rider weight. (bikes don't accelerate fast enough for rim weight to matter)
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Old 06-18-10, 08:00 AM
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Originally Posted by Speedskater
Some decade ago, a bike science group did a test. They put a black water bottle on the test bike, sometimes it was filled with lead and sometimes it was filled with air. The rider was not permitted to lift the bike or bottle. At the end of the tests, not much difference between air and lead. The only difference was the expected hill climbing horsepower to weight factor.
When weight matters, it's total weight not wheel weight, bike weight, or rider weight. (bikes don't accelerate fast enough for rim weight to matter)
while not trying to sound too contentious, i dont buy that one bit and id like to see a link to that article.

until i lose 100lbs, im more concerned with durability, not light weight, which, as another poster mentioned, doesnt mean i dont like nice parts or a nice bike and the nicer stuff, tends, by its nature to be lighter, so ill sum up my statement by saying lightness might be a byproduct, but isnt the goal...of this run on sentence

Last edited by grimace308; 06-18-10 at 01:11 PM.
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Old 06-18-10, 01:00 PM
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Originally Posted by Wogsterca
There is a sweet spot, like many other things, where up to that point you can lose a lot, for a relatively small investment. For example, say you have and older bicycle with steel bars, they are rusty and crusty, weigh 764g and are bent all to ****. Now for $35 you can get a nice AL bar, that weighs 310g, nice weight saving of a pound, they are not rusty or crusty and are a nice classic bar shape.
It's highly unlikely that anybody here is riding such a bicycle. And such a bike is likely going to be inordinately heavy in other places.

And even for $35, the one pound saving is going to provide an undetectable amount of performance. That is, there is no "sweet spot" for normal riders.

Tiny differences in performance are valuable to professional racers but the differences in performance are still tiny!

Originally Posted by grimace308
while not trying to sound too contentious, i dont buy that one bit and id like to see a link to that article.
See what the following says about the effect of weight. 20 oz of lead weighs 3.05 lbs.

https://noping.net/english/

Last edited by njkayaker; 06-18-10 at 01:29 PM.
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Old 06-18-10, 01:30 PM
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Originally Posted by grimace the magnificent
See what the following says about the effect of weight. 20 oz of lead weighs 3.05 lbs.
https://noping.net/english/
i fixed my line.

i am referring to rotating mass. i believe that race wheels, that weigh 1kg less that crappy "box" wheels, will be NOTICABLY easier on a dude, after 40 laps of a crit.

with the constant acceleration, dropping the cash for a set of custom light weight racing only wheels, was the best thing i ever did...billions of years ago.

i dont know if theyed make a pinch of squat, over the course of a flat road race, but when youre jumping 4 times a lap, i believe, they matter. i dont know if theyd matter in a rr with any constant speed climbing.
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Old 06-18-10, 01:40 PM
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Originally Posted by njkayaker
It's highly unlikely that anybody here is riding such a bicycle. And such a bike is likely going to be inordinately heavy in other places.


I haven't weighed it, but I'd guess it's about 35 pounds curb weight. And judging from what the bars looked like when I pulled the plugs out. I'll be looking for a set of those $35 aluminum wonders soon.

That calculator is fun. Removing 10 pounds, changing nothing else resulted in a 0.3 mph advantage. Moving from the tops of the bars to the drops resulted in a 3 mph advantage.

Last edited by Absenth; 06-18-10 at 01:43 PM.
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Old 06-18-10, 01:52 PM
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Originally Posted by grimace308
i fixed my line.

i am referring to rotating mass. i believe that race wheels, that weigh 1kg less that crappy "box" wheels, will be NOTICABLY easier on a dude, after 40 laps of a crit.

with the constant acceleration, dropping the cash for a set of custom light weight racing only wheels, was the best thing i ever did...billions of years ago.

i dont know if theyed make a pinch of squat, over the course of a flat road race, but when youre jumping 4 times a lap, i believe, they matter. i dont know if theyd matter in a rr with any constant speed climbing.
I'd bet money that you couldn't tell the difference if you rode the bike blindfolded. And you'd probably be surprised, if you could. Even in crits, aerodynamics beats weight.

Yes, there are real effects going on here, but they're tiny, less than 1%, and they're not something the rider can tell without reference to a stopwatch or speed gun.
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Old 06-18-10, 02:03 PM
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Originally Posted by njkayaker
It's highly unlikely that anybody here is riding such a bicycle. And such a bike is likely going to be inordinately heavy in other places.

And even for $35, the one pound saving is going to provide an undetectable amount of performance. That is, there is no "sweet spot" for normal riders.

Tiny differences in performance are valuable to professional racers but the differences in performance are still tiny!



See what the following says about the effect of weight. 20 oz of lead weighs 3.05 lbs.

https://noping.net/english/
The reason for replacing old crusty, rusty steel bars all bent to **** with new AL ones though has a lot more then simply the weight difference as the benefit, even if the weight was identical I would probably still want to replace an old crusty and rusty bars all bent to **** with newer ones. When it comes to weight difference though, a lot of it has to do with the amount of difference, and what is a detectable difference for example take 2 riders, both are 100kg, in fact they are identical twins who have the same athletic ability the same genetics, the same amount of experience, one has a bike that is 9.80kg and the other has a bike that is 9.79kg total for one is 109.9 the other is 109.79 a difference of 10g the bikes are identical except for the carbon bars, one has bars that are 10g lighter. I think that would be statistically insignificant.
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Old 06-18-10, 02:16 PM
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Originally Posted by Absenth
I haven't weighed it, but I'd guess it's about 35 pounds curb weight. And judging from what the bars looked like when I pulled the plugs out. I'll be looking for a set of those $35 aluminum wonders soon.
Crap! I knew there'd be one of you lurking in the shadows! It seem odd to me that the bars would be steel on that bike.

Originally Posted by Absenth
That calculator is fun. Removing 10 pounds, changing nothing else resulted in a 0.3 mph advantage. Moving from the tops of the bars to the drops resulted in a 3 mph advantage.
And removing 10 lbs from the base weight of a bicycle is hard/expensive to do!

The calculator is useful because it gives numbers instead of vague guesses. You should also report the absolute speed that those numbers are associated with. I suspect that the lower speed was somewhere about 18-20mph.

And there are people who obsess about weight and never ride in the drops (my club is full of people like that)! It doesn't make a lot of sense.

The problem with the "weight" argument is that (simplifying a bit) is that many people make the argument: "since Lance rides a light bicycle, I'll be able to ride like Lance if I get a light bicycle".

Last edited by njkayaker; 06-18-10 at 02:27 PM.
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Old 06-18-10, 02:21 PM
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Originally Posted by Wogsterca
The reason for replacing old crusty, rusty steel bars all bent to **** with new AL ones though has a lot more then simply the weight difference as the benefit, even if the weight was identical I would probably still want to replace an old crusty and rusty bars all bent to **** with newer ones. When it comes to weight difference though, a lot of it has to do with the amount of difference, and what is a detectable difference for example take 2 riders, both are 100kg, in fact they are identical twins who have the same athletic ability the same genetics, the same amount of experience, one has a bike that is 9.80kg and the other has a bike that is 9.79kg total for one is 109.9 the other is 109.79 a difference of 10g the bikes are identical except for the carbon bars, one has bars that are 10g lighter. I think that would be statistically insignificant.
Step away from the bong!! We aren't really talking about replacing broken crap.

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Old 06-18-10, 03:25 PM
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Originally Posted by Wogsterca
Now for $35 you can get a nice AL bar, that weighs 310g, nice weight saving of a pound, they are not rusty or crusty and are a nice classic bar shape. You can also for $197 go for a carbon bar that weighs 191g an additional saving of 119g, for only $280 you can get a carbon bar that weighs 189g a huge weight saving of 2g for $83. There are of course guys who will say that that 2g saving is worth $83 and those bars make them 16km/h faster. Most of us clydes would probably be happy with the $35 bars that are heavier, because we know that we can lose 119g, visiting the bathroom.
So I can shave off almost 5 ounces from my 20 pound bike for only $300? Who wouldn't do that? ( Anybody who knows the value of a dollar, probably. )

To be fair, though, I'm going to get a pair of CF brake levers when I find them on sale. I don't care about the gram they'll save me; it's the heat transfer. When I go kayaking in the snow, my CF paddle doesn't feel cold to the touch. But metal brake levers get cold, even when my gloves are in the wash.

Originally Posted by njkayaker
The problem with the "weight" argument is that (simplifying a bit) is that many people make the argument: "since Lance rides a light bicycle, I'll be able to ride like Lance if I get a light bicycle".
If you look at a high-end camera form, you'll see the same thing. It isn't that a particular hero has a better camera, but "If I pay $8,000 for this 'sports' camera, I'll be able to get good cyclocross photos. Because the problem with my pics couldn't possibly be that I haven't built up enough skill yet."
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Old 06-18-10, 03:52 PM
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Originally Posted by dscheidt
I'd bet money that you couldn't tell the difference if you rode the bike blindfolded. And you'd probably be surprised, if you could. Even in crits, aerodynamics beats weight.

Yes, there are real effects going on here, but they're tiny, less than 1%, and they're not something the rider can tell without reference to a stopwatch or speed gun.
aerodynamics trumps pretty much everything everything at speed, but we arent talking about aerodynamics. my point is that losing 1lb per wheel will be noticeable and you dont agree...fair enough. i agree that weight anywhere else wont matter, untill my paycheck comes from a pro tour team and im looking down the barrel of a grand tour.

i think if i raced a crit blindfolded, wheel weight would be the least of my concerns. there would be a redistribution of mass, approx 4kilos, from my midsection, to my bibs.

we need some physicists to save the day, or a calculator i havenet found.

assuming the hub is the same, id like to know how much less energy is needed, to propel a wheel to (x) rps, where the tire/rim combo is 3/4lbs lighter and the spokes are 1/4lbs lighter.

its time to head down the block and watch the uptown crit, in the NVGP. emilia fahlin...mmm mmm good
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Old 06-18-10, 03:52 PM
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Originally Posted by Seattle Forrest
So I can shave off almost 5 ounces from my 20 pound bike for only $300? Who wouldn't do that? ( Anybody who knows the value of a dollar, probably. )
I think (I hope) that Wogsterca is pulling our legs!

Originally Posted by Seattle Forrest
If you look at a high-end camera form, you'll see the same thing. It isn't that a particular hero has a better camera, but "If I pay $8,000 for this 'sports' camera, I'll be able to get good cyclocross photos. Because the problem with my pics couldn't possibly be that I haven't built up enough skill yet."
Spending money on things is easy. The other stuff is hard. I think one of the social "values" of light bikes and "weight weenyism" is that it is a convenient shared conversational topic (kind of like sports).

Last edited by njkayaker; 06-18-10 at 03:59 PM.
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Old 06-18-10, 03:58 PM
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Originally Posted by grimace308
aerodynamics trumps pretty much everything everything at speed, but we aren't talking about aerodynamics.
People should be talking about aerodynamics first. For many people, it's a free performance upgrade (and the best one) and one that they don't use!

Originally Posted by grimace308
my point is that losing 1lb per wheel will be noticeable and you dont agree...fair enough. i agree that weight anywhere else wont matter,
I haven't found any source that indicates the effect of the weight of the wheels (that is, weight on the rims, since weight at the hubs probably doesn't matter anywhere near as much).

What does "noticeable" mean? I suspect that some people might be able to notice a large difference in wheel weight when accelerating quickly but it's hard to say whether there will be any significant difference in overall speed for "normal" riding (which is where the value would be).
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Old 06-18-10, 04:07 PM
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Originally Posted by njkayaker
Spending money on things is easy. The other stuff is hard. I think one of the social "values" of light bikes and "weight weenyism" is that it is a convenient shared conversational topic (kind of like sports).
That, and talking shop is fun.

The first bike I bought as an adult, was from a shop run by a cranky old man near Golden Gate Park. I think he chased ten customers away for every bike he sold, but if you put up with the curmudgeonness, the guy knew his stuff. One thing he told me was that a front shock is great for occasional trails and city riding, if you don't have much skill on the bike, but that you can hop a curb pretty smoothly by pushing your weight over the rear wheel when you drop the front one, and then as far onto the front wheel as possible when you drop the rear. Now, I like having it both ways, so the idea of having a stiff bike but still being able to do dumb stuff occasionally, instead of getting a shock fork and always feeling it squish, was right up my alley. And that's pretty much been my philosophy ever since: see if there's a way to improve your skills to solve a problem, and only buy stuff as a last resort.
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Old 06-18-10, 05:30 PM
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Wow. This was one of the first threads I started, glad it became such a hot topic. Seems to me step one, train hard and ride the crap out of whatever you have. Step two,replace parts for quality and perfomance, not weight alone. Step three, lose weight and ride in an aerodyanmic position and go a lot faster (or keep eating but still go a little faster)
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Old 06-18-10, 05:37 PM
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I didn't worry about bike weight when at my highest weight of 210lbs. Now that I'm 145, I'm buying lighter wheels. And now I'm getting a new bike after a collision with an auto destroyed my steel bike. The drivers' ins sent me a nice big check to cover the damage.
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Old 06-18-10, 06:33 PM
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Originally Posted by njkayaker
What does "noticeable" mean? I suspect that some people might be able to notice a large difference in wheel weight when accelerating quickly but it's hard to say whether there will be any significant difference in overall speed for "normal" riding (which is where the value would be).
I can tell you that when I swapped out tires and tubes on my commuter (from light-weight road tires and light tubes to kevlar-belted tires and thorn-resistant tube) I added well over 1/2 lb. to each wheel far away from the axle. It makes a huge difference in acceleration but minimal once I get it rolling (I have less than 10" of elevation gain on my entire commute). As I commuting involves a lot of stops and starts, it has a real impact. Not getting flats is worth it to me but you can not say that it does not impact "normal" riding.
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Old 06-18-10, 07:02 PM
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Originally Posted by njkayaker
People should be talking about aerodynamics first. For many people, it's a free performance upgrade (and the best one) and one that they don't use!


I haven't found any source that indicates the effect of the weight of the wheels (that is, weight on the rims, since weight at the hubs probably doesn't matter anywhere near as much).

What does "noticeable" mean? I suspect that some people might be able to notice a large difference in wheel weight when accelerating quickly but it's hard to say whether there will be any significant difference in overall speed for "normal" riding (which is where the value would be).
they probably should be more talk about aerodynamice, but this thread is about weight. when the clyde aero thread starts, ill be there

in the world i frequent, id prefer not to have catastophic wheel faliure, mess up my already iffy, mug. that being said, starting up in traffic is where rotating mass comes into play, at least for me and i dont mind an easier time.

if the wheels are durable and im getting a super hookup, ill rock ksyrium elites no problem. if i cant buy 3 sets, i have no problem with the 32h 3x beater wheels (anchors) on my xbike.

i forgot where i was going with this, but since im such a wimp, i can tell when im expending less energy, getting going. i can tell wheels...i think.
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Old 06-18-10, 08:01 PM
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Originally Posted by CACycling
I can tell you that when I swapped out tires and tubes on my commuter (from light-weight road tires and light tubes to kevlar-belted tires and thorn-resistant tube) I added well over 1/2 lb. to each wheel far away from the axle. It makes a huge difference in acceleration but minimal once I get it rolling (I have less than 10" of elevation gain on my entire commute). As I commuting involves a lot of stops and starts, it has a real impact. Not getting flats is worth it to me but you can not say that it does not impact "normal" riding.
Nope. Bike wheels simply don't weigh enough to matter. The upper bound on the rotational energy in a wheel is its translational energy. (it's less, since much of the mass isn't at the outside of the rim, but it's friday, so I'll leave out the calculus.). As we all remember, that energy is = 1/2 m*(v^2).

To accelerate a 5 kg wheel from 0 to 10 m/s (about 22 mph) requires an input of

1/2 * 5 kg * (10 m/s)^2 = 250 J.

To do the same thing to a 1 kg wheel

1/2 * 1 kg * (10m/s)^2 = 50 J

That's a difference of 200 J for a silly heavy wheel, and an incredibly light one. Bicycles have two wheels, so we've got 400 J difference. Those joules are spread out in time, of course. Top flight criterium racers can produce about 0.2 g of acceleration. That's 2 m/s/s acceleration, so five seconds. 80 watt power difference; you'd notice that, for sure. There aren't many bikes with 5 kg (11 pounds!) wheels, except for those with the special lead rim strip. Actual changes will be much less.

That 1/2 lb you added? call it half a kilogram for both wheels, and the change in energy is

1/2 * .5 kg * (10m/s)^2 = 25 J.

If you can accelerate in top crit racer style, it would require five watts for five seconds. More likely is that the power output would be (roughly) constant, and the time to reach speed would be slightly extended. The energy needed for the rest of the bike, assuming 100 kg rider + bike, is 5000 J (and it's actually quite a bit higher; that's only the inertial resistance, air resistance is going to be substantial at 10 m/s). 25 J of 5000 J is one half of one percent; that's below the resolution of many power meters; I'm sure it's below the resolution of your legs.

The drag you feel in those wheels isn't from their weight. It's from their increased rolling resistance, or the placebo effect, or the glue I secretly put on your tires every night.
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Old 06-18-10, 08:08 PM
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Maybe I'm odd here, but I've never weighed any of my bikes. Not in over 45 years of owning and riding them. I just don't care. I'm much more interested in making sure everything works and that I can have a resonable expectation that the bike will get me where I'm going and back again.
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Old 06-18-10, 08:20 PM
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Originally Posted by njkayaker
The weight doesn't matter as much as people think.

The issue is the total load: bike + rider + load.

https://noping.net/english/
You seem to be putting quite a lot of faith into some random website. Are you sure it that it's able to accurately model the real world using simple polynomial equations?

BTW, if we signed you up for the Everest Challenge which bike would you rather ride? The 16lb bike? Or the 18lb bike? The calculator seems to suggest there should be little difference between the two. After 206 miles of riding and 29,000ft of elevation gain do you think that you, personally, would find it's predictions to be true?
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Old 06-18-10, 08:49 PM
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Originally Posted by sstorkel
You seem to be putting quite a lot of faith into some random website. Are you sure it that it's able to accurately model the real world using simple polynomial equations?
There are a number of assumptions built into that calculator. But the magnitudes are correct, and the equations are derived from actual measurement. (assumptions in Kreuzotter's calculator are things like frontal area as a function of mass and height, etc, to make the interface easier to use. analyticcyclling has a whole bunch more, and you can fiddle with all the variables you care to. )

Physics is a *****, man. It doesn't care what you paid for your bike. It's not going to be impressed that some salesman took your money. It only cares about forces, and simply put, weight doesn't matter nearly as much as people like to pretend it does.
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Old 06-18-10, 09:01 PM
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Originally Posted by Seattle Forrest
So I can shave off almost 5 ounces from my 20 pound bike for only $300? Who wouldn't do that? ( Anybody who knows the value of a dollar, probably. )

To be fair, though, I'm going to get a pair of CF brake levers when I find them on sale. I don't care about the gram they'll save me; it's the heat transfer. When I go kayaking in the snow, my CF paddle doesn't feel cold to the touch. But metal brake levers get cold, even when my gloves are in the wash.



If you look at a high-end camera form, you'll see the same thing. It isn't that a particular hero has a better camera, but "If I pay $8,000 for this 'sports' camera, I'll be able to get good cyclocross photos. Because the problem with my pics couldn't possibly be that I haven't built up enough skill yet."
I can see the CF brake levers, just remember that they are pretty much disposable if you crash and land on one. I can see your hands getting cold when the gloves are in the wash, because you should be wearing them when riding. I use a pair of full fingered MTB gloves when riding and my brake levers don't feel cold at all.

The biggest factor in bicycle performance, always has been and always will be the condition of the motor. In top seed racing when all the riders are similar condition and experience, saving a few grams may be a huge deal. Take a bunch of people out for some fresh air and exercise at a leisurely pace, a couple of kilograms may not make much difference. Saying that though, if I'm out with some guys for a road ride, I'll take the lighter weight road bike. Out to haul around a pile of camera equipment or some berries home from the market, I want the heavier bike, because it's got racks, fenders, lights which is to some degree why it's heavy. Now the road bike is getting a rim transplant over the winter, new wheels will be lighter, but the primary reason is that the wheels are chromed steel making it a fair weather bike, they are rusty and crusty, and can't be trued very easily.

I know what you mean about cameras too, the issue is the same though, it all comes down to who is holding the camera. There have been pro-level images taken with crappy cameras, there have been crappy images taken with high end cameras. I bought my first real bike and my first real camera the same year, 1978!
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