Weight to bike weight ratio

Discuss light weight issues concerning road bikes & parts.
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Superlite
Posts: 2492
Joined: Fri Aug 29, 2003 9:01 pm

by Superlite

Lets do another submitting of info. As you know, or should know the heavier you are the lighter the bike you have makes a bigger difference then a light weight person with a light weight bike. So everyone post your weight, and your rides weight. Please use Kilos and grams. Why Am I doing this? I dunno, just curious.

Weight 59K
Bike 7100g

8.3 Ratio

This just shows how much of a difference a lighter bike makes for you. The lighter you are, the less it matters, the heavier, the more. Thats why UCI should have weight limits for different weight classes of riders, then the little guys could get the same advantage. :wink:

by Weenie


Francois_Viviers
Posts: 175
Joined: Sat Oct 25, 2003 7:12 pm

by Francois_Viviers

Hmmm.... I think this should be more of a power to weight ratio, that would show a more realistic pciture of who would kick your but in a race, that would also make bike weight equally important for all. Usually riders power is expressed as watts/kilo so mine is sustainable

So mine is 365/68 = 5.37 watts per Kilo

When you add the bike and clothes into this, which would be a true reflection of what you would generate on the road it would be 365/74.5+- = 4.9 so for this a lighter bike woul be benificial for all as would a lighter body, but then again you need muscle mass to generate a lot of watts.

So the conlusion is that heavy parts and fat is the enemy of any weight weenie

Tim the Pineapple
Posts: 225
Joined: Fri Oct 31, 2003 10:30 pm

by Tim the Pineapple

Is this on flat or hill ?

Hill (Weight make huge difference on hills 85kg VS 65kg)

Benefit From Less Weight
This Much Less Weight 20 kg
Over This Distance 2000 meters
On Hill of Slope 0.03 Decimal
Faster by 35.35 s
Ahead by 246.75 m
Frontal Area 0.5 m^2
Coefficient Wind Drag 0.5 Dimensionless
Air Density 1.226 kg/m^3
Weight Rider & Bike 85 kg
Rolling Coefficient 0.004 Dimensionless
Power 250 watts

Flat

Weight make very little difference on flat that is if both riders are producing same watt.

Speed For Given Power Speed For These Parameters 11.16 m/s
Power 250 watts
Frontal Area 0.5 m2
Coefficient Wind Drag 0.5 Dimensionless
Air Density 1.226 kg/m3
Weight Rider & Bike 85 kg
Coefficient of Rolling 0.004 Dimensionless
Slope of Hill 0. decimal

VS

Speed For Given Power Speed For These Parameters 11.34 m/s
Power 250 watts
Frontal Area 0.5 m2
Coefficient Wind Drag 0.5 Dimensionless
Air Density 1.226 kg/m3
Weight Rider & Bike 60 kg
Coefficient of Rolling 0.004 Dimensionless
Slope of Hill 0. decimal

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manny
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Joined: Wed Dec 24, 2003 5:12 pm

by manny

How about this for consideration. Assume two identical bikes at the UCI limit and two riders using them, one weighs 130lbs and the other weighs 170lbs. The heavier rider based on weight alone is producing greater stress on the bike components and frame. This factor weakens the bike's ability to perform to the same level that it would perform for the lighter rider assuming an identical power output by both riders. The frame and components are vulnerable to flex based both on weight and force placed against them, in fact many manufacturers place weight limitations on frames and components based on the weight of the riders. The more inherent flex, the greater the possibility for loss of power transfer. If the above premise is true, does it not possibly negate any advantage perceived for the heavier rider? If I am not mistaken I believe certain members of this forum are engineers, and I defer to them for guidance on this issue.

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Superlite
Posts: 2492
Joined: Fri Aug 29, 2003 9:01 pm

by Superlite

Argh! Forget it.

Dude, the forces are not that great that the advantge would go away with 40 more pounds and more power. Point is the weight of the bike is in a lower ratio with a big guy vs. a small one.

And I'm talking about climbing, thats the only place weight really counts.
Last edited by Superlite on Sun Jan 18, 2004 12:42 am, edited 2 times in total.

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cyclemanpat
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Location: Kentucky, USA

by cyclemanpat

weight 69K
bike 5.7 K

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manny
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Joined: Wed Dec 24, 2003 5:12 pm

by manny

Dude, if you're only talking about climbing, then whatever advantage you think the heavier rider had based on the ratio is gone based on the added weight the heavier rider is required to move uphill. He has to exert greater wattage to climb at the same speed as the lighter rider.

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Superlite
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Joined: Fri Aug 29, 2003 9:01 pm

by Superlite

Manny wrote

How about this for consideration. Assume two identical bikes at the UCI limit and two riders using them, one weighs 130lbs and the other weighs 170lbs. The heavier rider based on weight alone is producing greater stress on the bike components and frame. This factor weakens the bike's ability to perform to the same level that it would perform for the lighter rider assuming an identical power output by both riders. The frame and components are vulnerable to flex based both on weight and force placed against them, in fact many manufacturers place weight limitations on frames and components based on the weight of the riders. The more inherent flex, the greater the possibility for loss of power transfer. If the above premise is true, does it not possibly negate any advantage perceived for the heavier rider? If I am not mistaken I believe certain members of this forum are engineers, and I defer to them for guidance on this issue.


OK, let me explain this better since I didn't to begin with.

Two riders, one weighs 60 kilos, the other 75 kilos. Both riding the same bike ( flex is not an issue, unless they were riding wet noodles). Both putting out the same power to weight ratio. The heavier rider would have the advantage because relative to him his bike has a lower weight, and his weight to the weight of the bike ratio would be greater, with the same work he would go faster then the smaller guy.

Does that make since to you? Cripes man, you sound like you just got out of philosopy 101, talk like a normal person. :twisted:
Last edited by Superlite on Sun Jan 18, 2004 3:56 am, edited 1 time in total.

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manny
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by manny

Sorry dude about the formal speech. I'm working on something at the same time I'm surfing. I've got to finish it today. Catch you later.

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spytech
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by spytech

172lbs/15.6lbs

and dude i think you should take intro to sociology because you are def. not good with people. @superlite

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Superlite
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by Superlite

Ouch, that hurts spytech. :oops:

But probley not as much as you crashing your bike into a car. :lol:

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spytech
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by spytech

it was not intended for it to hurt, but me and my bike were ok, bike never hit the floor or the car - like i said, i went sideways on the car to brake the fall to give me time to unclip. i am explaining again because i think you dyslexic or have ADD (Attention Deficit Disorder) and do not understand.

please play nice, and stop trying to cut everyones head off everytime someone goes a little off topic on your posts. im not an admin but your really pissing me off.

go here :arrow: http://www.add.org/

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Superlite
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Joined: Fri Aug 29, 2003 9:01 pm

by Superlite

No need to explain your crash again, I got it the first time, just making a little humor out of it.

Well spytech, I am sorry to be pissing you off. Obviously we have had some disagrement lately in different topics and that can be quite agraviting. And I have had one or two smart ass remarks. :wink: so that doesn't help. But I think it's time we both act more grown up. I apoligize for obviously pissing you off, but at the end of the day pissing people off isn't my goal, it's the opposite. Nobody is perfect, I'm a fine example of that, but we both need to losen up and respect each other. Peace.

P.S.

I actually have a mild case of ADD, so I don't find that funny. :shock:

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spytech
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by spytech

my smart remarks have been in retaliation to you, and things you do on the forum. its good that your end goal is not to piss people off, but you do it anyways. this is not about growing up, its about doing the right thing, and behavior in the forum; you snap to easy, you jump the gun with little nonsense, like someone saying something else on your post. these are the things that lead me to believe that you have ADD, if you have it at all. i was not making a joke out of it, it was simply my observation. just try to control yourself and how you speak on the forum.

P.S. our disagrement is just that a disagrement. when i disagree with you i do not go off on you, nor do i attack you, i usually question your response - lets keep it like that.
Last edited by spytech on Sun Jan 18, 2004 6:07 am, edited 1 time in total.

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Superlite
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Joined: Fri Aug 29, 2003 9:01 pm

by Superlite

I know, now lets hug! :wink:

by Weenie


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