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Arundel Chrono Aero Bottle Shoot Out!
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TOPIC: Arundel Chrono Aero Bottle Shoot Out!

Arundel Chrono Aero Bottle Shoot Out! 8 years, 7 months ago #7538

  • Jack Watts
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Armed with a sunny afternoon and two free hours, I decided to give this thing a try out at the track, mainly for two reasons: 1) I've used it a couple of times in TT's and anectodally, I went pretty fast with pretty poor wattage (I know, this is one step above the 'Slowtwitch' logic of "I have this friend, and he's fast...."), and 2) my TT bike's braking situation is so sketchy that I'm afraid to ride it in traffic anyway...but that's a subject for a different post.

The very gracious Rik O'Shea computed the data for me. While there is a laundry list of caveats, the test confirms what I anecdotally obvserved: for me, the bottle is faster.

A couple of general comments:
1) I'm not endorsing this particular bottle--who knows, a regular bottle may be even faster--I didn't test one, however (I thought of that after the fact).

2) Frame design/body position/pedalling style all probably have some influence on the bottle's effectiveness. My guess is if you're a skinny guy riding an Aluminum P3, however, the bottle *may* help. The other variable worth noting is that I have fairly wide hips, and tend to pedal 'knees in', almost brushing the top tube.

3) As Kraig would point out, I very well could do the same test and come up with a differnt result. With that much said, Rik seems pretty confident in the results, and the conditions were pretty good for testing, and since they confirm what I've observed in the past, I'll be using the bottle.

I was particularly curious since I remember reading Jens' comments that an aero bottle on his P3 was significantly worse in the tunnel--but that was not pedalling, at zero yaw (IIRC).

Lastly, in case you don't think tires make a difference, the Crr I showed previously was .0075. That's a .0043 difference--with one tire!! I know everyone who reads this forum is down with rolling resistance, but this really jumped out at me. 400 gram training tires are really slow....

Here are Rik's comments also r.e. the test:
"The data was fairly good and and the results indicate that "with bottle" provides a statistically significant better CdA.
Notice that run 3 (with bottle) and run 4 (without bottle) have studentized residuals of 5 and -6 indicating that they maybe outliers (although only very slightly so). If I remove them the r^2 or "goodness of fit" is 99.92% and 99.96% which is excellent i.e. a very well executed set of tests. In this case the gap between CdA with/without bottle is narrowed but still indicates that with bottle is better."

W/O Bottle:

Cda .2366 Crr .0032

With Bottle

Cda .2299 Crr .0032

Re: Arundel Chrono Aero Bottle Shoot Out! 8 years, 7 months ago #7541

  • Mulefoot
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What tire has a Crr of .0075?

Re: Arundel Chrono Aero Bottle Shoot Out! 8 years, 7 months ago #7550

  • Jack Watts
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Mulefoot wrote:
What tire has a Crr of .0075?


Oh, it's worse that that--I had a low rr tire on the front, and that one on the rear--it's probably over .01.

I'm not even going to bother w/the brand, since I don't want to seem like I'm bad-mouthing a tire I got for free at some race...and I think it's an OEM tire anyway, which you can't even buy aftermarket.

It's more about the construction than the brand, anyway. It's something like 30 T.P.I. with plastic sidewalls and the rubber seems to be about 4 mmm thick (seriously)...and I don't think anyone here's in danger of going off to the races with it.

One note on the rolling resistance of .0032. I used a Michelin Pro Light 700x20 front, Pro 2 Race 700x23 rear, Michelin Latex tubes (the fat ones), on a bumpy concrete track. I'm guessing that even a bumpy concrete track really is faster than asphalt.

Re: Arundel Chrono Aero Bottle Shoot Out! 8 years, 7 months ago #7559

  • jkheycke
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Neat. Thanks for sharing this! Of course, this means I'm going to have to go out and test this too. I'll probably start with one of the Campy biodinamicas I still have around.


-jens

Re: Arundel Chrono Aero Bottle Shoot Out! 8 years, 7 months ago #7561

  • gregclimbs
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jkheycke wrote:
....Campy biodinamicas I still have around.


-jens


PLEASE I hope that I the testing shows they are SLOWER I sold mine a LONG time ago for top $ on ebay and I would hate to regreat that...


:O

g
wattagetraining.com

Re: Arundel Chrono Aero Bottle Shoot Out! 8 years, 7 months ago #7562

  • gtingley
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Jack Watts wrote:
Armed with a sunny afternoon and two free hours, I decided to give this thing a try out at the track, mainly for two reasons: 1) I've used it a couple of times in TT's and anectodally, I went pretty fast with pretty poor wattage (I know, this is one step above the 'Slowtwitch' logic of "I have this friend, and he's fast...."), and 2) my TT bike's braking situation is so sketchy that I'm afraid to ride it in traffic anyway...but that's a subject for a different post.

The very gracious Rik O'Shea computed the data for me. While there is a laundry list of caveats, the test confirms what I anecdotally obvserved: for me, the bottle is faster.

A couple of general comments:
1) I'm not endorsing this particular bottle--who knows, a regular bottle may be even faster--I didn't test one, however (I thought of that after the fact).

2) Frame design/body position/pedalling style all probably have some influence on the bottle's effectiveness. My guess is if you're a skinny guy riding an Aluminum P3, however, the bottle *may* help. The other variable worth noting is that I have fairly wide hips, and tend to pedal 'knees in', almost brushing the top tube.

3) As Kraig would point out, I very well could do the same test and come up with a differnt result. With that much said, Rik seems pretty confident in the results, and the conditions were pretty good for testing, and since they confirm what I've observed in the past, I'll be using the bottle.

I was particularly curious since I remember reading Jens' comments that an aero bottle on his P3 was significantly worse in the tunnel--but that was not pedalling, at zero yaw (IIRC).

Lastly, in case you don't think tires make a difference, the Crr I showed previously was .0075. That's a .0043 difference--with one tire!! I know everyone who reads this forum is down with rolling resistance, but this really jumped out at me. 400 gram training tires are really slow....

Here are Rik's comments also r.e. the test:
"The data was fairly good and and the results indicate that "with bottle" provides a statistically significant better CdA.
Notice that run 3 (with bottle) and run 4 (without bottle) have studentized residuals of 5 and -6 indicating that they maybe outliers (although only very slightly so). If I remove them the r^2 or "goodness of fit" is 99.92% and 99.96% which is excellent i.e. a very well executed set of tests. In this case the gap between CdA with/without bottle is narrowed but still indicates that with bottle is better."

W/O Bottle:

Cda .2366 Crr .0032

With Bottle

Cda .2299 Crr .0032


I would be intereted to see how this bottle works on a P3C

Re: Arundel Chrono Aero Bottle Shoot Out! 8 years, 7 months ago #7569

  • JV
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jkheycke wrote:
I'll probably start with one of the Campy biodinamicas I still have around.


The cage/bottle interface on the old Campy is a lot less smooth than the Arundel carbon cage and how it matches up with the bottle. I wonder if this makes one "good" and the other "bad" (for a simplistic view).

Re: Arundel Chrono Aero Bottle Shoot Out! 8 years, 7 months ago #7652

  • mcw2109
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what do you guys think of this one?
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... otohosting

I bought one that was identical but a different color last summer and only used it once. That TT didn't go so well, so I didn't use it again, but I'm thinking about testing it out again.
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