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PostPosted: Fri Aug 08, 2014 4:04 pm 
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Location: by Crystal Springs (Sawyer Creek Trail)
Specialized typically test at 30 mph afaik.


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Posted: Fri Aug 08, 2014 4:04 pm 


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PostPosted: Fri Aug 08, 2014 5:44 pm 
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I'd love to see a one-inch steel frame undergo the same tests, like my Ritchey Breakaway which gets the vast majority of my miles these days.[/quote]

https://www.youtube.com/watch?v=XE_GKePa3CQ

1" bikes are just a little bit better than today's huge tubed climbing bikes.[/quote]

Specialized recently upload a slew of Wind tunnel tests https://www.youtube.com/results?search_query=win+tunnel
I paused when they show metrics on the monitor. Looks like all tests were done with 50kph wind. Who rides in 50kph wind?

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PostPosted: Fri Aug 08, 2014 6:15 pm 
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The speed range of 30 kph and 50 kph are extremely small in aerodynamics consideration, so the relationship is more linear relating drag and velocity. This allows an easy scaling factor to be used to determine drag at a speed lower than your test speed.


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PostPosted: Fri Aug 08, 2014 8:42 pm 
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mpulsiv wrote:
I paused when they show metrics on the monitor. Looks like all tests were done with 50kph wind. Who rides in 50kph wind?


50kph gives more consistent and reliable data but is still scalable down to 30-40kph for more everyday riders. It is industry standard, hed, zipp, trek, etc all use 30mph/50kph for the same reasons.


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PostPosted: Fri Aug 08, 2014 8:51 pm 
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Wait, are we talking about linear speed or headwind? Even if its scalable down to 30-40kph. That's a lot of wind to face! I've never ridden in a wind over 15kph and if it gets this high it's seasonal (late fall and winter).

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PostPosted: Fri Aug 08, 2014 9:12 pm 
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Well the bike is stationary, so the equivalent to the road is rider + wind speed...

35kph into 5kph effective wind = 40kph in the tunnel.


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PostPosted: Fri Aug 08, 2014 9:15 pm 
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The 30mph is pure wind flow and they usually spin the wheels at an equivalent rate.

That could equate to 20mph road speed into a 10mph head wind in the real world or any other variation as long as the combination is equal to 30mph.


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PostPosted: Fri Aug 08, 2014 9:21 pm 
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Chader09 wrote:
The 30mph is pure wind flow and they usually spin the wheels at an equivalent rate.

That could equate to 20mph road speed into a 10mph head wind in the real world or any other variation as long as the combination is equal to 30mph.


All tests were performed in metric speed. Lets stick to km/h. Baseline was 50 km/h, does that mean it's ~40 km/h road speed and ~10 km/h of headwind?

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PostPosted: Fri Aug 08, 2014 9:57 pm 
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mpulsiv wrote:
All tests were performed in metric speed. Lets stick to km/h. Baseline was 50 km/h, does that mean it's ~40 km/h road speed and ~10 km/h of headwind?

First, I am not the only who listed something in MPH.

Second, yes. Your calculation is correct.

As long as you compare values in the same units (km/h to km/h) the same statement stands.

Real Road Speed + Straight Head Wind = Wind Speed

Wind Speed is the same as the Wind Tunnel Speed.

1+1=2, pick whatever units you like and use the same ones in the calculation. It all works out the same.


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PostPosted: Fri Aug 08, 2014 10:10 pm 
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Chader09 wrote:
mpulsiv wrote:
All tests were performed in metric speed. Lets stick to km/h. Baseline was 50 km/h, does that mean it's ~40 km/h road speed and ~10 km/h of headwind?

First, I am not the only who listed something in MPH, so lighten up.

Second, as long as you compare values in the same units (km/h km/h) the same statement stands.

Real Road Speed + Straight Head Wind = Wind Speed

Wind Speed is the same as the Wind Tunnel Speed.

1+1=2, pick whatever units you like and use the same ones in the calculation. It all works out the same.


I take all this quite lightly. Brain hurts from all this aero-ish data with marginal gains. More drag with aero frame + aero wheels (~$5000 investment) than race-fit jersey. Guess what my next upgrade is going to be. Downsizing my race-fit jersey from Medium to Small.

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It Never Gets Easier, You Just Go Faster!


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PostPosted: Sat Aug 09, 2014 12:09 am 
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wkwt wrote:
Test rode an Emonda SL 6 black on black yesterday. Still very comfortable compared to my Domane 5 but clearly stiffer, snappier, and livelier. This might just be because the Domane is long and super-absorbing, so compared to a Tarmac there might be less difference. I was amazed at how much of the downtube you could see sticking outwards below the top tube (from above). There is no discussion of aero anything with this frame.


Wow -- so someone here rode the frame! That answers the question, then, of why anyone would ride it -- it is "livelier" and "stiffer" and "snappier" than the Domane, and perhaps also the Madone.

Sounds like a good reason to me.

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PostPosted: Sat Aug 09, 2014 11:11 am 
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I continually have trouble trying to figure out whether you are sarcastic or serious. I suggest a different font color! 8-)

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PostPosted: Sat Aug 09, 2014 12:27 pm 
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Funny :).

I'm not being sarcastic here -- if the frame rides better, it rides better. There must be some reason Trek Racing is willing to ride with the frame. You can't argue with success. (whoops -- that actually was sarcastic...)

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PostPosted: Sat Aug 09, 2014 1:14 pm 
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Rides better than a Domane. And a subjective statement at that? Ok...

I've ridden into a 30 kph headwind before, not fun.

If you want to give up 15-20 watts, go right ahead.

I already have an aero frame and wheels (and clothing that fits, why would you buy anything that flaps around?)


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Posted: Sat Aug 09, 2014 1:14 pm 


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PostPosted: Sat Aug 09, 2014 11:12 pm 
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I can't keep track of who these guys are mad at. Hilarious.

None of us have access to testing equipment other than a scale, so yes, I will trust how my legs and body feels over what a marketing department tells me is going to happen at 25 mph alone. Having said that, I had a Madone 5 and enjoyed it.


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