# Aerodynamics and water bottle cages



## Pelvic_Banana (Jun 30, 2009)

According to this article, a water bottle cage on the seat tube is more aero than on the downtube. 

http://www.bicycling.com/article/0,6610,s1-4-41-21048-2,00.html

I love having my polar bottle on the downtube, just feels intuitive to reach down there. But hell, if I'm more aero with a bottle on the seat tube, I'll go for it. I've got a camelbak chill jacket bottle, and that fits nicely on my bike's seat tube.

My question is, is this information correct? Did wind tunnel testing confirm this? 

Another question is if a bottle cage, say on my downtube, were empty when I was riding, would the cage create more drag than if it were filled with a bottle? Does the same principle apply for the cage on the seat tube? How much more aero are carbon cages to aluminum ones, and are carbon cages more aero without bottles than compared to aluminum cages without bottles?


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## muscleendurance (Jan 11, 2009)

Of course, you found it on the net didnt you.


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## newmexrb1 (Aug 16, 2009)

My hunch is that if you're wondering bout a fraction of a Newton of drag, you be posting in the wrong place. Might try the save some weight forum. Dunno for sure. Many of us here on the noobs corner are more concerned with 20+ POUNDS of excess baggage. :cryin:


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## jaredmx5 (Aug 31, 2009)

I have bottle cages on both the downtube and seattube, it's like a freakin parachute!


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## newmexrb1 (Aug 16, 2009)

jaredmx5 said:


> I have bottle cages on both the downtube and seattube, it's like a freakin parachute!


Brevity is the soul of wit.


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## Pelvic_Banana (Jun 30, 2009)

newmexrb1 said:


> My hunch is that if you're wondering bout a fraction of a Newton of drag, you be posting in the wrong place. Might try the save some weight forum. Dunno for sure. Many of us here on the noobs corner are more concerned with 20+ POUNDS of excess baggage. :cryin:


I'd use livestrong.com for the calorie tracking system, as well as the support of friendly people on the various diet forums. I'm still a beginner learning ever since I got my first real road bike. I'm using the bike fir fitness, commuting and general experimentation in ideal characteristics of a bike for me.

I'm doing things like adding or subtracting a rack, bottle cages, lowering my stem, etc. to experiment with different speeds, utilities and comfort. So far so good.


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## newmexrb1 (Aug 16, 2009)

Thats all cool and I salute your efforts to get more fit and have fun doing it.The question about water bottle cages might concern an advanced rider trying to break the world record for distance in an hour with a motorcade breaking wake. 

So whether you have an aero water bottle or not is truly a tempest in a tea pot. This is a crazy sport in many ways. People worry about grams of weight and slight aerodynamic advantages. Weight matters on hills and aero otherwise. But not as much as one might suppose if you're a recreational rider and starting out. 

I suspect the most important part of the equation at this point is making it as comfortable and fun as possible. For sure, find other riders--a great reality check, and put your wallet away. Make sure the bike fits!!!!! If that costs a 100 bucks, well worth it.


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## tihsepa (Nov 27, 2008)

This whole thing is a joke right?

OP, I would try to stay away from that bicycling.com site. Unless you like useless repetitive information.


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## newmexrb1 (Aug 16, 2009)

Dunno. Giving the benefit of the doubt but seems I recall banana has been here before--some kind of research??


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## andulong (Nov 23, 2006)

If you don't need two bottles you are probably not riding enough anyway!


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## Pelvic_Banana (Jun 30, 2009)

newmexrb1 said:


> Dunno. Giving the benefit of the doubt but seems I recall banana has been here before--some kind of research??


I prefer to go by Pelvic, and yeah, I'm still a noob. No, there is no conspiracy here. stop being so paranoid.

The Bicycling website isn't too bad, especially with the articles about road rights. I need help with stretching my hip flexors, positioning my cleats, and a whole bunch of stuff. I've been satisfied with their breadth of content, for whatever it's worth.


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## OldItalian (Feb 14, 2009)

Try this if you are really worried. Ride 5 miles with the bottle Then ride the same 5 miles and this time no bottle. See if you notice any aero advantage on the second run.
Dont worry about it.


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## newmexrb1 (Aug 16, 2009)

Pelvic_Banana said:


> I prefer to go by Pelvic, and yeah, I'm still a noob. No, there is no conspiracy here. stop being so paranoid.
> 
> The Bicycling website isn't too bad, especially with the articles about road rights. I need help with stretching my hip flexors, positioning my cleats, and a whole bunch of stuff. I've been satisfied with their breadth of content, for whatever it's worth.


I was recalling this event

As I said, i'm willin to give you the benefit of the doubt. And my replies were meant to be helpful. I have no idea what a pelvic banana even is. But bananas fit the particular question.

BTW what is a pelvic banana?


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## Fredrico (Jun 15, 2002)

*As usual, they're full of crap.*

No less an authority than John Cobb, the guy who did wind tunnel testing with Lance, published a study years ago, that concluded a water bottle on the downtube was more aero than two behind the seat, as trialthletes were fond of doing. He didn't say anything about it being more aero on the seat tube, probably about the same as on the downtube. It's round, just where you want it, right behind the front wheel. It's also low and close to the center of gravity, so has minimal effect on handling, if anything, making it more stable, and its much easier to grab than one on the seat tube or behind the seat. I seem to remember, Cobb also found the empty cage generated more air turbulence than with a bottle in it, not that the amount would slow you down. By far the most drag is the rider's upper body.


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## milkbaby (Aug 14, 2009)

From studies by Chester Kyle about increases in aerodynamic drag: 0.6% increase from hair on limbs, 0.9% from long socks, 4.2% from loosely fit clothing. Also for an athlete moving at a speed of 10 meters per second, a reduction in drag of 2% may result in a time savings of 0.1% or less than 15 seconds over 4 hours at 22 miles per hour. Nothing beats training better for improving athletic speed for your average joe!


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## Opus51569 (Jul 21, 2009)

OldItalian said:


> Try this if you are really worried. Ride 5 miles with the bottle Then ride the same 5 miles and this time no bottle. See if you notice any aero advantage on the second run.
> Dont worry about it.


I just tried this, and added 50kph to my average speed... Who knew???


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## tihsepa (Nov 27, 2008)

Hire this guy to chase you. That will make you faster.


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