Kissena Forum Archive

Bicycle Pictures and Videos

4908 comments · 90771 views
that was great !

Ouch

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the bestest...
What's old is new. A wooden bicycle. 
http://www.bbc.co.uk/news/business-28122309 
Jules said:
Ouch

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Always win the hit.
Early Sunday Brooklyn Bridge views. Never not awesome.

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Min 38: bush league tactics.  If I were Vos, I'd be embarrassed by my teammates.

http://www.youtube.com/watch?v=PRskFaxzZiY
This just blows my mind.  Really???

http://www.youtube.com/watch?v=DZnrE17Jg3I
Said it before, will say it again. It's garbage. Look at that his riding position. He might as well be standing up and wearing hammer pants.
Ain't nothing un-aero about that...

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The shaved legs thing: they seem to have tested several athletes, so position would presumably be averaged out. Makes me wonder if arm hair is making a difference.
Joaquin said:
The shaved legs thing: they seem to have tested several athletes, so position would presumably be averaged out. Makes me wonder if arm hair is making a difference.
Agree on both counts.  Doesn't matter if they were standing or seated; they were testing for a delta in absolute terms.


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They were testing at 50kph (31mph) so the time improvements they cited would be different at lower speeds. Aero drag increases at an exponential rate as wind speed increases rather than linearly. At half the speed (15mph) you'd get less than half the benefit.
Actually, not exponential:
F_D\, =\, \tfrac12\, \rho\, v^2\, C_D\, A
F(D) is the drag force. v is the velocity. But C(D) is the drag coefficient which in a laminar flow situation (low Reynolds number) is also proportional to velocity. So that means the F(D) is roughly related to velocity cubed.
Thus, to compare relative drag forces at 40 km/hr vs. 50 km/hr, calculate the ratio of (40*40*40)/(50*50*50), which is about 0.5. This is consistent with the calculator at the Science of Cycling site, which specifies a power output of 162 W vs 317 W required for 24 mph and 30 mph, respectively.
Bye the way, it was George Stokes who introduced the concept that led to the Reynolds number, but Osborne Reynolds who later got credit for it. No matter, fluid dynamics is characterized by Navier-Stokes equations and old George is also known for Stokes' theorem, Stokes' law and various other mathematical tidbits.


EDIT: wrong thread!
Stokes with the knowledge hammer! What I got out of that is my beer gut causes drag.
Stokes - that calculator clearly doesn't take into account rolling resistance, mechanical drag in the drivetrain and the anchor that I drag around with me. Just seems way too easy to maintain 24mph per the calculator.
We are talking about leg shaving, which would not affect those other resistance factors.
The look on Keith's face says it all:

http://nyvelocity.com/gallery/image/12092?page=2#comment-118626
Slaying the Badger on ESPN July 22nd. Excited for this. 

http://espn.go.com/30for30/film?page=slayingthebadger


The shit you see on a ride....This thing could come in handy....I thought about giving it a hand up from the gutter...you gotta hand it to the guy who threw this out...Idle hands are the devils playground...I know firsthand that these roads are filthy..this is hands down the craziest thing I've seen today...things are getting out of hand...this appears underhanded...    I'm tired.....
What is that, an arm?  Weird.
Slaying the Badger on ESPN July 22nd. Excited for this. 




Saw it in the theater. Rules. Anyone want to host a get together for this?
Damn.

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http://cyclingtips.com.au/2014/07/bikes-of-le-tour-katusha-and-movistars-canyon-aeroad-cf-slx/

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I must have missed the memo on these...

http://cyclingtips.com.au/2014/07/lotto-belisols-ridley-bikes-at-the-tour-de-france-3/

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He's getting really good at making those.
buy a pair.

https://hanseeno.myshopify.com/collections/shoes/products/u100g-shoes

THey're a steal at 2,000 euro.

"The price reflects the 42+ hours that go into making a single pair and the 8 molds that are required. They are not cheap by any means but you do get a shoe under 95 grams, hence the name U95. (4-8 week delivery time)."
I just want to remind everyone that " Slaying the badger" is on ESPN tonight at 8:00PM
Another showing on Saturday in case you didn't set your DVR in time for today (like me).