"PRO" Cycling Discussion

Questions about bike hire abroad and everything light bike related. No off-topic chat please

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KWalker
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by KWalker

petepeterson wrote:No Tyler Farrarrrr
He needs to reinvent himself as a classics guy or something.


He just needs to go down a notch until he can stay upright and be more consistent.
Don't take me too seriously. The only person that doesn't hate Froome.
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by Weenie


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Tinea Pedis
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by Tinea Pedis

You slated them.

Based off a claim that no one was making.

justkeepedaling
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by justkeepedaling

petepeterson wrote:
justkeepedaling wrote: What do you mean what is aero about the RCA? The tubing is Kamm profile. It's more aero than a Scott Foil yet hundreds of grams lighter.


Oh really? Can I please see the data? How come TT bikes and cervelos own S & P bikes don't have the Kammmmm?


There's data in the Cervelo RCA white paper. A full yaw spread.

Image

Kamm is not as aero as full airfoil for the majority of the frame locations, but it's definitely a lot more aero than round tubes. There is direct comparison of the RCA vs the Cannondale Evo and Trek Madone KVF. TT bikes and the S series are made for pure aero. Despite that, even the P5 has some Kamm tail profiles.

The RCA is for all around aero, stiffness, and light weight. The Addict is missing the aero portion of that.
I suggest you read the white paper

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by nathanong87

the norway road champs was sooo good. thor was so amped! something about yelling Norwegians for commentary

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elviento
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by elviento

Truncation =/= Kamm

Not according to Wunibald Kamm. Otherwise a square could be Kamm.

BTW, Navadauskas is strong with a lot of potential. He could be the next Hesjedal and better.
Last edited by elviento on Thu Jun 27, 2013 5:39 am, edited 1 time in total.
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KWalker
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by KWalker

Tinea Pedis wrote:You slated them.

Based off a claim that no one was making.

Vaughters made it himself in an interview and twitter. A poster, who I quoted in my response also made it. Perhaps you were too busy trying to snipe at my opinion to notice that. Some of the riders are strong, but just the team itself I do not think is as impressive as Vaughters feels it is.
Don't take me too seriously. The only person that doesn't hate Froome.
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justkeepedaling
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by justkeepedaling

elviento wrote:Truncation =/= Kamm

Not according to Wunibald Kamm. Otherwise a square could be Kamm.

BTW, Navadauskas is strong with a lot of potential. He could be the next Hesjedal and better.


Huh? By definition a square doesn't have any truncation... Kammback or Kamm airfoils have a smooth curve profile that would typically end in a point but has the tail cut off such that the flow mostly acts like the tail is still there. That's a Kamm airfoil. Slight radius curve to the corners of the chopped section can reduce the increase in pressure drag from cutting off the tail. That has nothing to do with a square. By definition a Kamm airfoil starts with a full airfoil profile which has the tail truncated. It has to be a TAIL that's truncated. Where the truncation is conducted is dependent on the airfoil design. But the leading edge is airfoil shaped

airwise
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by airwise

justkeepedaling wrote:The RCA is for all around aero, stiffness, and light weight. The Addict is missing the aero portion of that.
I suggest you read the white paper


I can't see the white paper testing the new Addict, nor is it comparing any of these bikes with true aero frames. Finally it's not making clear the totally insignificant "savings" this test shows.

I like the RCA but not because the marketing team at Cervelo claim it to be "aero".

justkeepedaling
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by justkeepedaling

It's very clear. Approximately 100 grams drag saving over a round tubed bike like the Sl4 and Cannondale Evo. Which are very close to each other in terms of drag as will be any other round tubed bike (aka Addict) which has no consideration for aero. That's approximately 10 Watts of power saved at 25 mph. That's near a minute of time saved over a 40 km course. It's the difference between a bike with no bottles on it and a bike with two bottles on it.

I love it when every single major manufacturer has developed techniques to design aero features and all have data showing that it is real and spending tens of millions of dollars for people to just dismiss it altogether.

The RCA would be under 600 grams with no aero consideration, but the bike is reasonably aero, and is only slightly behind pure aero bikes like the S5. The fact that the RCA is so spectacular all around is the reason why it is an incredible achievement. Ask anyone in the peloton if they'd reject a bike that is even lighter than what they're riding now, at least as stiff, but with a free 10 watts on top.
Last edited by justkeepedaling on Thu Jun 27, 2013 7:39 am, edited 1 time in total.

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elviento
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by elviento

JKP -- your definition is correct. It's just not on the RCA.
Last edited by elviento on Thu Jun 27, 2013 8:03 am, edited 1 time in total.
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justkeepedaling
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by justkeepedaling

What do you mean before the launch? Aero was always part of the design process for the RCA. Even before the bike was conceived it was planned to be incorporated for the design. That's part of what CASE stands for... They did extensive parametric studies with CFD and wind tunnel validation. And the RCA does have a Kamm profile. Squoval 3 is exactly that. One type of it.

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elviento
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by elviento

Kamm needs a taper. Squoval 3 does not have a taper (unless you count the rounded corners). In other words, you truncate the "TAIL", not the "MID SECTION".

BTW, I edited my last message to delete some of the subjective stuff.
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micky
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by micky

elviento wrote:BTW, Navadauskas is strong with a lot of potential. He could be the next Hesjedal and better.


Errrr.....not really mate.
He's a good rider, decent TTer and just finding recently to be quite good at sprints and that's way different from Hejedal.

airwise
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by airwise

justkeepedaling wrote:That's approximately 10 Watts of power saved at 25 mph. That's near a minute of time saved over a 40 km course.


I shall be most annoyed then if that big Canadian or Dan Martin don't win the Tour :lol:


I love it when every single major manufacturer has developed techniques to design aero features and all have data showing that it is real and spending tens of millions of dollars for people to just dismiss it altogether.


Their marketing departments aren't yet clever enough to hoodwink everyone. :wink:

Meanwhile the top European magazines (Le Cycle and Tour) continue to tell us the best two bikes on the planet are the Canyon SLX and the Cannondale Evo - both with nary a thought for these enormous aero gains some are trying to convince us riders of. Go figure.

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elviento
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by elviento

Ever wonder why, after investing millions in tunnel and CFD, they all come out saying theirs is the fastest? So most of the money is wasted coz only 1 of them can be right?

Banter aside, I think the truth is, manufacturers invest to improve designs (good for them), but some of the tests are done a bit more favorably to themselves, plus marketing guys can also get a bit optimistic.

Over time, one can tell some brands tend to be a bit more optimistic than others. Just like claimed weights. Especially when drag is so much harder to verify.
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