Bike weight and the myth of ‘fast’ bikes

[cnighbor1]

Bike weight and the myth of ‘fast’ bikes
Read more at http://velonews.competitor.com/2014/08/news/bike-weight-myth-fast-bikes_339880#oXOd78L1wvqwLBhq.99

''
Editor’s Note: This excerpt is adapted from the book FASTER: Demystifying the Science of Triathlon Speed by Jim Gourley and republished with permission from VeloPress. Learn more about the science of triathlon at freetrispeed.com.

Let’s clear something up. There is no such thing as a “fast bike.” Bikes are neither fast nor slow. Bikes are shiny or expensive. Bikes have a lot of mass or a little. Without a rider, they are stationary. Physics holds a bike in place until you get on it and start pedaling. Even then the bike may not necessarily be fast. Of all the equipment on your bike, your legs are the most critical component. There are plenty of nice bikes on the road that are being ridden slowly.

But more insidious than inaccurate vocabulary is a simple overestimation of how much bike weight matters for most riding.

In FASTER, I show the math that explains why just a degree or two of incline makes riding a bike feel so much harder. Riding up a hill, it may seem more important than ever to dump any and all extra mass we can from our bikes. That’s the allure of a carbon fiber bottle cage, an upgrade to carbon fiber cranks, handlebars, stem, carbon saddle rails, or wheel spokes. Five grams here, 10 grams there, it all adds up, right? Pretty soon, you’re 500 grams lighter. That’s half a kilogram!

True. But such upgrades could easily total $500 or more, which is also half a grand. Is it worth it?

Not exactly.

A good approximate difference between an entry-level aluminum bike with a decent set of components and a top-of-the-line carbon model with some of the lightest components on the market is just shy of 3.25 pounds.

Was the weight loss worth it?

Let’s find out. Take a hypothetical rider and have her ride two bikes up a hill at the same speed. The first bike weighs 15 pounds and the second bike will shave off the 3.21 pounds to weigh in at 11.79 pounds. For each test, we’ll have her ride at 15 mph. Everything is constant, except for the bike, so what we ought to see is a reduction in the power required to get up the hill. That’s the real test of your savings.

Refer to the second image, above, for a graph of the results.

If you’re having trouble telling what the difference is, save yourself the eyestrain, because there isn’t much — that’s the message.

But pro athletes use the lightest equipment they can, so there must be something to it, right?

Remember that professional athletes operate in an entirely different environment than the rest of us. They are all very close to each other in terms of fitness, and they are also all very close to being the absolute best a human being can be.

Beyond that, our result also makes intuitive sense: 3.21 pounds is just over 2 percent of the total weight of our 150-pound cyclist and 15-pound bike. Ten watts is 2 percent of the 500-watt power requirement to maintain speed up a 10 percent grade. Because the weight-to-power savings ratio is linear, we should expect that one-to-one relationship.

The implication is a bitter pill, though. If you want to reduce the power requirement by 1 percent, you have to reduce the total mass that’s moving up the hill by 1 percent. And because you’re moving both your body and the bike up the hill, a measly 1 percent equates to a whole lot of grams before you see returns on your carbon investment.

In short, you’re much better off upgrading your legs and dropping body fat through proper training and diet. In fact, losing unnecessary weight would have a dual impact on your power and speed. As weight decreases, the amount of power required to maintain a certain speed will also decrease. At the same time, the amount of power you are capable of generating should actually increase. This is because oxygen uptake is related to body mass and improves as fat is lost.

Wattage vs. time

If the power argument doesn’t quite satisfy you, we can look at it another way. Let’s answer the question you really care about: How much faster does it make me? After all, you win races by saving time, not watts. Let’s see what will happen when our hypothetical rider rides bikes of varying weight up different hills. We’ll hold power at a constant 200 watts and have her ride up a 1-mile climb at seven different grades (1–7 percent).

Let’s look at the difference between 15-, 16-, 17-, and 18-pound bikes, with the 18-pound bike serving as the baseline. Because of the complexity involved, we’ll eliminate air resistance and analyze the impact of weight reduction only. How much time do we save?

A graph of the results is in the third image above.

Read it and weep, weight watchers.

Look at the far right of the graph. Take 3 pounds off your bike, pedal at a constant rate of 200 watts, and you’ll get to the top of a 7 percent climb a whole 7.5 seconds ahead of the competition. A 1-pound advantage only puts you ahead by 2.5 seconds. Over the course of an hours-long race, a few seconds per climb is not a significant advantage.

Keep in mind that the advantage only holds when the climbs are long and steep. Courses with fewer and shorter ascents will keep the difference small. ''

Read more at http://velonews.competitor.com/2014/08/news/bike-weight-myth-fast-bikes_339880#oXOd78L1wvqwLBhq.99

[witcombusa]

Yeah, but does she plane :p

[sitzmark]

So why the endless debate and dragging out of the obvious?

Buy a Huffy and call it a day. If you want to spend a little more and like something "svelte" buy it and go ride. ... just ride. Life is really pretty simple.

[c-record]

I don't disbelieve what's said but cycling is also not a steady-state effort. If someone is accelerating from 26 mph to 32 mph and I have to respond to that effort I'll do whatever it takes to get me there. If I don't respond in the available window the chance is gone. I don't get it back. I'm dropped.

Lighter wheels and lighter stuff helps. It's all relative though the premise of the authors argument is true and allows us to laugh at ourselves.

[nmrt]

huh...weight not a big deal?
So, a 1 lb lighter bike is 2.5 sec faster over 1 mile. I think that is a LOT!
Next time I'm on my 30 mile ride, my PR should lower by a whopping 75 sec just by decreasing by bike mass by 1 lb. Coming from a running background, 75 sec difference would put a smile on my face.

[zap]

I've been in this sport a long time....no longer racing but still like to hit it. Anyhow, having owned a few bikes and taken several home to test, I've developed a taste for light reliable bikes.

[verticaldoug]

after I lose 10 lbs, I'll ask my bike to lose one.

[Daveyk]

Using the example from above, (I think) you would only save the 75 seconds if your 30 mile ride was all going up hill at a 7 degree grade.

huh...weight not a big deal?
So, a 1 lb lighter bike is 2.5 sec faster over 1 mile. I think that is a LOT!
Next time I'm on my 30 mile ride, my PR should lower by a whopping 75 sec just by decreasing by bike mass by 1 lb. Coming from a running background, 75 sec difference would put a smile on my face.

[nmrt]

Welcome to Colorado!
:-)

Using the example from above, (I think) you would only save the 75 seconds if your 30 mile ride was all going up hill at a 7 degree grade.

[Daveyk]

Thanks. I think I need stay in New England with with the gentle rolling hills.



Welcome to Colorado!
:-)

[aramis]

Using the example from above, (I think) you would only save the 75 seconds if your 30 mile ride was all going up hill at a 7 degree grade.

That would be a tough ride.

I'm all for nice stuff, but I think the point is an 18# bike at $1500 is pretty darn close to a $8000 15 # bike as far as performance goes. Getting obsessive over it isn't worth it and working on making yourself faster is always going to be more important.

You can always go out and get that 15# bike later. You can't just go buy more fitness for yourself.

[Ralph]

How about in Florida.....where we don't have a lot of hills? (well....generally speaking.....some 12-15% grades near me, but don't ride there often)

[CunegoFan]

I hope the book deals with the BS of stiffer bikes being faster. It is infuriating reading people make ridiculous claims about a bike is so much faster than another; they can "feel" it. Uh-huh.

[11.4]

Honestly, he shows two lines on a graph with the axes so exaggerated that they appear to overlap. That's just how you draw the graph.

And his little chart at different speeds? He jumps from a statement of what he's going to prove to a final graph with nothing in between? There's nothing about how he calculated this, what his assumptions are, just that he did a lot of data processing to remove effects of wind resistance and maybe other variables, and then a result that one can't understand or verify?

If this excerpt is any indication, his book is just a badly done argument that you should lose weight and gain in various measures of strength. Those are obvious. But the real effect of the weight difference deserves better analysis than this. I'm not asking to see a justification of using titanium water bottle cage bolts versus stainless ones. But if one compares a basic Shimano 105 Trek to a nicely done but fully-standard equipment Dura Ace Di2 top-end frame with nice wheels and tires, there's a lot more than 3.2 lbs there. And with slightly different assumptions one can up the wattage differences to something very significant. Not that saving even 8 lbs on one's body wouldn't be more helpful than 8 lbs on the bike, and probably cheaper too, but this book is supposedly aimed at triathletes who, at least in many cases, are already at relatively low body fat. So is he saying that he's only writing this book for fatty triathletes? Excuse me, but the cycling community deserves better.

[oldpotatoe]

huh...weight not a big deal?
So, a 1 lb lighter bike is 2.5 sec faster over 1 mile. I think that is a LOT!
Next time I'm on my 30 mile ride, my PR should lower by a whopping 75 sec just by decreasing by bike mass by 1 lb. Coming from a running background, 75 sec difference would put a smile on my face.

I think the point is losing 5-10 pounds off you more effective, better for you, just harder......where'd I put my beer???

[cnighbor1]

we all missed the obvious simply plug the three main tubes and fill with helium!!
Jan Heine has been revisiting this subject for a long time. some of his comments agree with the author.

[witcombusa]

Thanks. I think I need stay in New England with with the gentle rolling hills.


You need to ride past the city limits if you really think that is true!

[11.4]

I think the point is losing 5-10 pounds off you more effective, better for you, just harder......where'd I put my beer???

I fear you are right and this is all there is. And this is a worthy subject for a whole new book? At least offer some analysis, or something new. That is such an un-original subject that the acquisitions editor at Velopress should be shot. Small wonder they are up for sale.

[Ralph]

I realize for racers the situation is a little different.....but for me and the guys I ride with regularly.......none of us have 11 lb bikes, and while a couple guys may have 15 lb bikes without pedals, bottle cages, etc......most of us are riding with two large full bottles, and 2-3 lbs of tools and spares under our seats. A full large water bottle weighs 2-2.5 lbs. Lately, although I ride with an older group, it is a well heeled group who can afford to ride anything they wish.....our bikes are pretty loaded down with what you need in this 95 degree weather and spares for 40-50 mile rides. We're not weighing stuff to see who can get up the next hill first, and our bike weight can vary a lot depending on how much liquid and spares we carry. It's more about that than about my bike is lighter than your bike. I can feel a large water bottle on the bike, but not interested in leaving it home.

[moose8]

I have a heavy bike and a light bike and the light bike definitely feels faster to me going uphill. Makes me wonder if it really is or it's just some bias on my part.

[Daveyk]

Don't really think it's true. But, we don't want to get into an our mountains are bigger than yours discussion with our friends in Colorado.

You need to ride past the city limits if you really think that is true!

[Masher]

Love these type of threads...

Heavier bikes is faster going down hill... Discuss

Lighter bikes is faster going uphill... Discuss

Mtb bikes are faster than roadsides on singletracks.... Discuss.

Roadies are faster than mtb on tarmac.... Discuss.

Fun but ultimately pointless discussions.

[aramis]

I hope the book deals with the BS of stiffer bikes being faster. It is infuriating reading people make ridiculous claims about a bike is so much faster than another; they can "feel" it. Uh-huh.

I don't know why it bugs me, but when people talk about a bike and say stuff like it "glides up hills with ease" or "spins up and accelerates super fast" it really does. I always feel like these are the people that never ride? I've never gone up a long climb and felt like I was gliding. :bike:

Laterally stiff and vertically compliant and all that.

[fogrider]

I hope the book deals with the BS of stiffer bikes being faster. It is infuriating reading people make ridiculous claims about a bike is so much faster than another; they can "feel" it. Uh-huh.

stiffer = more responsive and quicker acceleration. talk to anyone at the velodrome or a sprinter...look at Mark Cavendish's bikes, its all about stiffness and aerodynamics. and while weight savings will make you slightly faster, it can make a big difference in acceleration when the break happens and you need to jump on the last wheel going by.

[bewheels]

Hmmm...
I get that there are better ways to lose weight.
I get that he is speaking to triathletes.
But whether it is 2 seconds or 6 seconds, it means you got dropped.

I think the arguement is better kept at the level of "there are other things to consider then the bike when focusing on improvements ". But the simple fact is that people like their gadgets, it can be easier to focus on how to reap gains from gadgets then change one's behavior, and a certain population really likes well made things and if that means applying a variety of rationalization around those desicions (weight, stiffness, etc) then so be it.

[witcombusa]

I realize for racers the situation is a little different.....but for me and the guys I ride with regularly.......none of us have 11 lb bikes, and while a couple guys may have 15 lb bikes without pedals, bottle cages, etc......most of us are riding with two large full bottles, and 2-3 lbs of tools and spares under our seats. A full large water bottle weighs 2-2.5 lbs. Lately, although I ride with an older group, it is a well heeled group who can afford to ride anything they wish.....our bikes are pretty loaded down with what you need in this 95 degree weather and spares for 40-50 mile rides. We're not weighing stuff to see who can get up the next hill first, and our bike weight can vary a lot depending on how much liquid and spares we carry. It's more about that than about my bike is lighter than your bike. I can feel a large water bottle on the bike, but not interested in leaving it home.


Let's not confuse the discussion with reality... ;)

[cfox]

So the author writes that it's a myth that lighter bikes are faster uphill, then goes through a lot of trouble to show that it's actually not. Um, 7.5 seconds? Look at your watch and count that off. In the context of a race, that is a lifetime. Yes, yes, we all know the author's premise is correct, and it's near impossible to quantify the difference given different riders, but it's ridiculous for him to attempt to use "science" to prove his point when it proves the exact opposite. Like written by someone else, he could have just said weight is better lost on your body than your bike and left out the charts and graphs. No wonder triathletes are so grumpy; they're subjected to crap like this.

[oldpotatoe]

I fear you are right and this is all there is. And this is a worthy subject for a whole new book? At least offer some analysis, or something new. That is such an un-original subject that the acquisitions editor at Velopress should be shot. Small wonder they are up for sale.

No..old news for sure. Velopress for sale? Didn't know that. Are they still part of the 'Velo' family??

[bewheels]

No..old news for sure. Velopress for sale? Didn't know that. Are they still part of the 'Velo' family??

Here you go... Velonews/Velo for sale (http://www.bicycleretailer.com/north-america/2014/07/31/competitor-group-interested-selling-velo-magazine-and-velopress#.U-dQ5oBdVig)

...Competitor Group is trying to lighten their load to move more quickly :)

[oldpotatoe]

Here you go... Velonews/Velo for sale (http://www.bicycleretailer.com/north-america/2014/07/31/competitor-group-interested-selling-velo-magazine-and-velopress#.U-dQ5oBdVig)

...Competitor Group is trying to lighten their load to move more quickly :)

""(VeloPress publisher) Ted Costantino and (Velo editor in chief) Neal Rogers have done a great job managing VeloPress and VeloNews, and Competitor Group have been shrewd stewards of the brands these past six years," Magowan said. "It would be a privilege to again be involved with assets that are so loved by consumers, retailers and the industry."

I heard about Velo being on the block..hey, I know all these guys..Rogers, Ted, Felix..all great guys...it'd be great to have it all be local again..

[witcombusa]

So the author writes that it's a myth that lighter bikes are faster uphill, then goes through a lot of trouble to show that it's actually not. Um, 7.5 seconds? Look at your watch and count that off. In the context of a race, that is a lifetime. Yes, yes, we all know the author's premise is correct, and it's near impossible to quantify the difference given different riders, but it's ridiculous for him to attempt to use "science" to prove his point when it proves the exact opposite. Like written by someone else, he could have just said weight is better lost on your body than your bike and left out the charts and graphs. No wonder triathletes are so grumpy; they're subjected to crap like this.

Well, 99% of the bike world doesn't race and shouldn't care. If my 3 hour loop could be done 10 minutes sooner with a 15# bike, I'd have just lost 10 minutes of fun...;)

[cfox]

Well, 99% of the bike world doesn't race and shouldn't care. If my 3 hour loop could be done 10 minutes sooner with a 15# bike, I'd have just lost 10 minutes of fun...;)

Yes, but this is an excerpt from a book titled 'Faster', written specifically for racers (triathletes).

[Yossarian]

I'm sure everyone here has seen these videos before, the makers even have a road bike version. The how to be a mountain biker video 25 seconds in says it all, and anyone who was or is involved in the arms race will identify.

https://www.youtube.com/watch?v=WPVRU7jSYkQ

[CunegoFan]

stiffer = more responsive and quicker acceleration.

Quantify it. Instead of bro science, let's see measurements or like can be done with weight, let's see a model that can calculate the time lost. Produce numbers that will show whether stiffness loses two seconds a kilometer or something neglible, like 0.002 seconds, that no one will care about.

[Charles M]

Same bull shot different day...

Stats are what they are. Physics is what it is. (and trolls will always ask you to prove it rather than posting info that disproves it)


Saying weight (and aerodynamics) doesn't matter is simply not true. Virtually all sports play this out, from lighter pads in football to lighter shoes in track to lighter wheels (and everything else) in F1...

Weight matters. Aerodynamics matters...


The guys trying to tell other people how much it (weight / aero) matters either lack the knowledge needed to speak about it and or just hide from it in order to sell themselves just as much as companies overstating these values do so to sell equipment.

[e-RICHIE]

Same bull shot different day...

Stats are what they are. Physics is what it is. (and trolls will always ask you to prove it rather than posting info that disproves it)


Saying weight (and aerodynamics) doesn't matter is simply not true. Virtually all sports play this out, from lighter pads in football to lighter shoes in track to lighter wheels (and everything else) in F1...

Weight matters. Aerodynamics matters...


The guys trying to tell other people how much it (weight / aero) matters either lack the knowledge needed to speak about it and or just hide from it in order to sell themselves just as much as companies overstating these values do so to sell equipment.

What matters is the right weight, not as little of it as possible. Some parts are
too light. The sum of some of these parts can also be less than efficient atmo.

ps

arrange disorder

:cool::cool::cool:
;););)
:rolleyes::rolleyes::)

[ergott]

Yeah, physics 101 goes out the door on both sides of the argument.

Weight matters. By how much? It depends. The real answers is it depends.

I don't know what's worse, our need to be spoon-fed answers or the journalistic drivel that appeals to that.

[nbl78s]

I've always been told an ounce of spinning weight is equal to a pound of static weight... A 17# bike with a light frame and heavier wheels definitely feels more sluggish and less responsive than a 17# bike with a heavier frame and light wheels.

[ergott]

I've always been told an ounce of spinning weight is equal to a pound of static weight... A 17# bike with a light frame and heavier wheels definitely feels more sluggish and less responsive than a 17# bike with a heavier frame and light wheels.
Sorry, but it's not true. It would be great for business if it was.

There is a difference in handling, but weight saved on the wheels is virtually the same as losing it on the bike.

[oldpotatoe]

I've always been told an ounce of spinning weight is equal to a pound of static weight... A 17# bike with a light frame and heavier wheels definitely feels more sluggish and less responsive than a 17# bike with a heavier frame and light wheels.

Yikes....now tell me what an orange tastes like.

[Pete Mckeon]

plenty of experience and knowledge. Lightness has a price in many ways but if that gets you on the bike to ride than you become happier

What matters is the right weight, not as little of it as possible. Some parts are
too light. The sum of some of these parts can also be less than efficient atmo.

ps

arrange disorder

:cool::cool::cool:
;););)
:rolleyes::rolleyes::)

[Stephen2014]

we all missed the obvious simply plug the three main tubes and fill with helium!!
Jan Heine has been revisiting this subject for a long time. some of his comments agree with the author.

Or hydrogen and an ignition switch that goes off if it's diagonal for too long!

[bluesea]

It says a 3lb lighter bike is 7.5sec faster on a 1mi course at 7% slope. Imo that's a substantial improvement attainable without the use of borderline weight weenie specific components.

[Anarchist]

Is there anything the people here won't argue about?

[Bstone]

Well, they all seem to like bikes. Maybe they wouldn't argue that bikes are bad.

[Ti Designs]

Thanks. I think I need stay in New England with with the gentle rolling hills.

Like Lincoln Gap?