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PostPosted: Tue Apr 25, 2017 9:50 am 
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Indoor velodrome

..........................................Watts required at 45kph
Hand position: ........................Hoods......Drops.....Aero on Hoods

Trek Madone Race Shop Ltd...........301.6.....299.1.......279.1
Specialized S-Works Venge ViAS......301.6.....300.1.......286.1
Canyon Aeroad CF SLX.................307.6.....295.2.......281.5
Cervelo S5...............................309.2.....306.5.......281.1
Giant Propel Advanced SL.............343.0......332.6.......298.0

http://www.cyclingweekly.com/news/produ ... GYfV3zG.99

"Prior to each run, temperature, air pressure and system weight were recorded. A coefficient rolling resistance was measured and calculated. By subtracting the watts required to overcome drive train friction and rolling resistance, we are left with the aero watts – our comparative measure (the watts required to drag at 45kph).

These are presented for each bike for three different riding positions – the hoods, the drops and riding in a low aero position on the hoods. For consistency, the bikes were set up in as close a riding position to each other as possible and the same wheels were used in all the bikes. The reason for this is that we wanted the variable to be the bike frame itself and not the rider or wheelset.

The wheels were a set of Fast Forward F9Rs with a Power Tap G3 rear hub for power measurement. For reference, 1W equates to 0.1 second per kilometre, as a rule of thumb.

Limitations should also be pointed out – testing in an indoor velodrome has the advantage of good run repeatability and consistency. The main disadvantage is that wind yaw angles can be lower than those that can be experienced on the road, particularly when riding at slower speeds.

While every effort was made to get the bikes in the same riding position, the Canyon had a slight advantage with 41cm wide bar, while the others all had 42cm.

It should also be pointed out that slightly different handle bar shapes will undoubtedly create slight differences, hence the decision to test each bike in three positions. Coefficient of variance was very good lap to lap, of around 0.8-1.3 per cent across all test runs. Test velocity was typically 48kph (13.3m/s) and air density was 1.1663kg/m3."


Last edited by User Name on Tue Apr 25, 2017 1:19 pm, edited 1 time in total.

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PostPosted: Tue Apr 25, 2017 10:06 am 
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Read this as well, seems like they did what they could to control the environment.

Results wise it looks like there's no significant difference, maybe only for the Propel vs. other 4 on hoods/drops.


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Posted: Tue Apr 25, 2017 10:06 am 


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PostPosted: Tue Apr 25, 2017 10:08 am 
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There's something seriously hinky going on with those results.

The Canyon and Giant had 12 and 10 watt changes between hoods and drops, the others had 1.5 to 2.5 watt changes between those same positions. And that discrepancy is as big as the whole margin between the bikes, if you exclude the Propel.

It also asks us to believe that switching from riding a Madone to a Propel makes a 16 times greater aero difference than switching from the hoods to the drops on the Madone. Nope nope nope.


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PostPosted: Tue Apr 25, 2017 10:13 am 
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The S5 has compact drops so that would explain the reason it did (comparatively) poorly to say the Aeroad which has deep drops. Makes perfect sense.

Interesting then that the drops on the S5, Madone and VIAS are pretty much useless. Lucky to save a watt or two. May as well chill on the hoods and save your back until you're ready to go aero hoods and go full gas. Have to admit it, hoods to aero hoods figures are scary. Not sure I can face riding on the hoods normally again :lol:

EDIT: worth noting that Cav doesn't use Cervelo's aerobars, he uses the ENVE's which are deeper.


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PostPosted: Tue Apr 25, 2017 10:58 am 
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Quite a different result than what Tour Magazine came up with a year ago, especially for the Propel.

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PostPosted: Tue Apr 25, 2017 3:42 pm 
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Yeah I do not put much validity on this. If they don't run the same bar width and the same cockpit setup as control, then any small changes could easily be attributed to the cockpit. Either way though, to me this shows how relatively small the differences are between the bikes. So in my opinion, the one you felt best on would be the one that makes you the fastest.

Also, using 90mm wheels is fine, but why not also do the test with a pair of 60s... I find in my local racing that most people are on 60s, which could make one frame different than the others.

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PostPosted: Tue Apr 25, 2017 3:45 pm 
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Location: UK
Quote:
For consistency, the bikes were set up in as close a riding position to each other as possible and the same wheels were used in all the bikes. The reason for this is that we wanted the variable to be the bike frame itself and not the rider or wheelset.
Read more at http://www.cyclingweekly.com/news/produ ... oC4ZODY.99


So not identical? How close were they? If the giant was an inch shorter and more upright for example surely this would be very significant? To be a meaningful test surely the position would need to be identical, not just as close as possible??

Col.


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PostPosted: Tue Apr 25, 2017 7:33 pm 
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Guys, don't try to find a logical argument behind the results of these tests. There is not one... Just an inside game of companies and magazines that has nothing to do with science.

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PostPosted: Tue Apr 25, 2017 7:48 pm 
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Exactly these kind of so called tests are only to draw people to a site or magazine.
A marketing trap. Tests work as a magnet on people. It's a psychological thing.


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PostPosted: Tue Apr 25, 2017 8:11 pm 
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They're also fun and generate a bit of chat. Nothing wrong with it. And besides, I bet the data is valid and repeatable. These guys got the results they did for a reason. They won't tell the full story, and that's for us to fill in - which is the fun part.

If you have any of these bikes you're a lucky man. It's all good.

I'd have liked to see a more traditional frame used as a control, but no company would 'allow' that I bet.


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PostPosted: Tue Apr 25, 2017 8:26 pm 
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Shrike wrote:
, I bet the data is valid and repeatable.

.


:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:
C'mon this is cycling weakly you're talking about....

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PostPosted: Tue Apr 25, 2017 8:39 pm 
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what are the frame sizes, wouldn't be to difficult to use the same bars, and use different stem positions to get as close as possible to identical setup.

the jump up to the propel could easily be accounted for by rider position in the wind.


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PostPosted: Tue Apr 25, 2017 10:47 pm 
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I think this actually tells a lot about efficiency of certain postures and cockpit configurations. Specialized put a lot of effort into those goofy bars, obviously with an emphasis on riding hoods (where people spend most of their time). And this demonstrates they were reasonably successful.
It looks like the complete cockpit integration of the Vias, Madone, and Aeroad are worth something (perhaps more than the frame?)
And the flappy cables hanging off the Propel aren't aero (shocker)

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PostPosted: Tue Apr 25, 2017 11:13 pm 
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Imaking20 wrote:
Specialized put a lot of effort into those goofy bars, obviously with an emphasis on riding hoods (where people spend most of their time). And this demonstrates they were reasonably successful.

How do you figure that?


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PostPosted: Tue Apr 25, 2017 11:56 pm 
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So do we have to add the watts for drive train and rolling resistance to these numbers to get the actual watts required for "45kph" in the velodrome? Even in a calm day 300w in an aero position with forearms on on the tops buys me closer to 40kph outside


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Posted: Tue Apr 25, 2017 11:56 pm 


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