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Discussion Starter · #1 ·
I've looked and couldn't find any scientific information saying that a lighter bike is easier to pedal than a heavy one. I know it's easier to climb and sprint with a light bike. I also read that they both are almost the same on the flats. I know that from my own riding anyhow. Anyhow I have a discussion going on with a neighbor about this.
He's an engineer and he's telling me I can ride a lot faster on the flats with a light bike and if I want to get a good workout I should be using a heavy bike. I say I do have a heavy bike and it's really not that much faster with the lighter bike. He's says maybe not, but you will use less energy with the lighter bike.I'm trying to get something to prove this point.Thanks.
 

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ReviewBikeRoad Member
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I personally think heavier bike will fatigue you sooner than a light bike.

I have an old Schwinn that weighs 34 lbs, and a new bike that weighs 20 lbs.

Longest ride on the Schwinn = 40 miles.
Longest ride on the new bike = 70 miles.

I can just go longer on my new bike before getting tired.
 

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vexatious enigma
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This coming from a person with a Look bike as their avatar. Is that your heavy bike? If so then we really need to make a trade here.

I find it hard to believe that you cant find ANY scientific evidence on this. I mean --- Ive always been lead to believe that this is common physics in action here. I am of the opinion that you will go faster for longer with a light weight and stiff bike.
 

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Adventure Seeker
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Compared to the weight of the rider, virtually all road bikes are light. What's more of a factor is drag and rolling resistance vs. weight.
 

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You're right, never mind what my legs say. Lets all go out and buy heavy bikes. There's no proof, then I ain't buyin it.
 

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Hucken The Fard Up !
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Peanya said:
Compared to the weight of the rider, virtually all road bikes are light. What's more of a factor is drag and rolling resistance vs. weight.
this is a fallacy being repeat here too often

it is true that when you are just cruising softly inside your comfort zone, the weight differences don't make much difference.

But when you are close to your limits, ( climbing steep gradients, very long rides, high speeds etc ) the weight and aero characteristics work on your favor exponentially.
 

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In the flats? Nah, probably won't make much difference. Lighter and more aero tubulars will probably make a difference, but that's about it.
 

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asgelle said:
And what does rolling resistance depend on?

As for scientific evidence, the OP should show his engineer friend this http://www.recumbents.com/WISIL/MartinDocs/Validation of a mathematical model for road cycling.pdf and while he's at it, ask this so-called engineer why a heavy bike gives a better workout than a light one.
Rolling resistance depends on total weight. The argument that people are making is that the difference between a heavy and light bike in regards to the total weight of bike plus rider yields a negligible difference in rolling resistance.

And what exactly in that PDF are we looking at?
 

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Salsa_Lover said:
this is a fallacy being repeat here too often

it is true that when you are just cruising softly inside your comfort zone, the weight differences don't make much difference.

But when you are close to your limits, ( climbing steep gradients, very long rides, high speeds etc ) the weight and aero characteristics work on your favor exponentially.
I think for the most part what you feel when going to a lighter bike is usually not weight but a "quicker" geometry and better stiffness allowing you to accelerate quicker.

It is not a fallacy that the percentage of weight from the bike is small when compared to the overall weight of the rider and bike.

The bike I ride around for errands weighs in at something like 35 pounds with the bags. I rode it empty to Lowes the other day, and came back with three gallons of DryLock Paint, a ten pound container of cement patch, four paint rollers, a wire brush and three 12 ounce bottles of concrete etch. If you do the math, the load weighed more than the bike. I really didn't notice a lot of difference on the way home on the hills or the flats other than a bit of frame flex since this frame isn't the most rigid one out there. My speeds were pretty much the same as the way there.

I'm not saying the added weight had no effect, I'm saying that if adding over 35 pounds didn't cause a huge difference in my speed then 1 to 5 pounds won't make a whole lot of difference. 1 to 5 pounds is a very small percentage when compared to the overall weight of the bike and rider, that isn't a fallacy, it is a mathematical fact that can be computed.
 

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Minjin said:
And what exactly in that PDF are we looking at?
I'm looking at the equation of motion for a bicycle with rider which could easily be differentiated with respect to mass to quantitatively evaluate the effect of weight on the speed of a rider at fixed power.
 

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George M said:
He's an engineer and he's telling me I can ride a lot faster on the flats with a light bike and if I want to get a good workout I should be using a heavy bike.
Engineer? He must drive a train.
For argument sake let's say he's right that lighter bikes are faster on the flats. The rider is in control of how much of a workout he gets on any weight bike. You don't get more of a workout with a heavier bike, you just go slower. You don't get less of a workout with a light bike, you just go faster.

But that's moot because for all practical purposes he's wrong about the lighter bike being faster on the flats too. You get to your speed quicker (better acceleration in other words) but cruising speed is more or less the same.
 

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Jay Strongbow said:
But that's moot because for all practical purposes he's wrong about the lighter bike being faster on the flats too. You get to your speed quicker (better acceleration in other words) but cruising speed is more or less the same.
You sure you have enough qualifiers in there? For many cycling applications 6 mph is the same as 30 mph, so yes cruising speed may be "more or less" the same with a lighter bike, but since cruising speed depends inversely on rolling resistance and rolling resistance is linear with total weight (bike + rider), and further since there are no retarding forces that scale inversely with weight, reducing bike weight can only increase speed on the flats
 

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Discussion Starter · #16 ·
Jay Strongbow said:
Engineer? He must drive a train.
For argument sake let's say he's right that lighter bikes are faster on the flats. The rider is in control of how much of a workout he gets on any weight bike. You don't get more of a workout with a heavier bike, you just go slower. You don't get less of a workout with a light bike, you just go faster.

But that's moot because for all practical purposes he's wrong about the lighter bike being faster on the flats too. You get to your speed quicker (better acceleration in other words) but cruising speed is more or less the same.

Thank you, that's exactly what I was trying to tell him.:thumbsup:
 

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asgelle said:
You sure you have enough qualifiers in there? For many cycling applications 6 mph is the same as 30 mph, so yes cruising speed may be "more or less" the same with a lighter bike, but since cruising speed depends inversely on rolling resistance and rolling resistance is linear with total weight (bike + rider), and further since there are no retarding forces that scale inversely with weight, reducing bike weight can only increase speed on the flats
Is today national pedantic day or something? I've posted about 5 times and got one spelling correction and now this. Sorry if 'more or less' isn't up to your standards of internet chat but it's a friggin bike site and I'm not here looking for a nobel nomination.
 

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Jay Strongbow said:
Is today national pedantic day or something? I've posted about 5 times and got one spelling correction and now this. Sorry if 'more or less' isn't up to your standards of internet chat but it's a friggin bike site and I'm not here looking for a nobel nomination.
well if you're talking c0ck, that's what you get :thumbsup:
 

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Jay Strongbow said:
Is today national pedantic day or something? I've posted about 5 times and got one spelling correction and now this. Sorry if 'more or less' isn't up to your standards of internet chat but it's a friggin bike site and I'm not here looking for a nobel nomination.
You think it's pedantic, fine. I think it's important to at least get the trends right. Add weight and bikes go slower except on down hills; remove weight and they go faster. How much depends on the specifics of the bike, rider, and course. In no case does it stay the same. Whether the amount is important depends on the particular goals of the rider. For many riders, 10's of minutes don't matter, for others, races have been decided by tenths or hundredths of a second.
 
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