What was the basis for the calculation that an aero 'ring and crank are worth 7 and 11 seconds over 40K, respectively?

I've looked, and have had a hell of a time finding anything quantitative on rings and cranks.

not buying that one

You made me go double check, the only data point is from a german magazine, and nobody knows exactly the nature of the aero crank in question, so it is a bit of a wild guess there:

http://sheldonbrown.com/...ero/aerodynamics.htm

while checking I noticed the wild guess was a bit high though and have reverted it down a bit. If you notice anything us suspect let me know.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

Here's why I learned:

• Always spend $$ on tires first
• Get a sleeved tri-suit that fits great - if I do another Ironman, I will probably do a full change into an actual skinsuit, may even be worth it for a 70.3
• Don't bother buying a deeper wheel (zipp 303 is squarely in the "good enough" category)
• I may have to ditch the Specialized Evade for a real aero helmet - but only if I'm willing to test at ERO or do it myself. I suspected I was giving up time when I switched from the Giro A2, but I have no idea how much.

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/kj

http://kjmcawesome.tumblr.com/

Maybe change the name slightly.... "AeroWeenie Wild Aero Guess".

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Find out what it is in life that you don't do well, then don't
do that thing.

It's all there in the fine print.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

there is one other datapoint on aero cranks, which is the zipp claim of 9 seconds for their old aero crankset

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

9 for that vs 18 for summation of previously now changed points :)

you don't sum them.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

I don't care what it says, I'm not buying CeramicSpeed BB or jockey wheels.

Well that is pretty much what the app says. Don't buy those...or at least buy them last.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

Hello jackmott and All,

Nice!

Thanks for including skewers .... :)

.

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Cheers, Neal

+1 mph Faster

Jack, the guys at Torhans made this claim about their aero30 bottle. Does this sound reasonable to you?

In fact at a recent wind

tunnel test with Pro Triathlete Andrew Starykowicz the Aero 30™ reduced the total drag of his bicycle by 50

grams, or 5 watts of power. That was over using NO hydration system at all. The benefit of the Aero 30™ will

allow Andrew to ride ~1:50 faster in an Ironman, while staying hydrated in the aero position.

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Find out what it is in life that you don't do well, then don't
do that thing.

one question: for tires, does the calculator take into account the crr only or combo of crr and cda?

I know two people who were physically present for that test, so I don't think the claim is a complete invention. I don't know if it was done with rider on the bike or not. With rider off, it might not be real, with rider on, 50g has a lot of +/- on it.

and I only get 1:13 per ironman florida time savings from 50g drag reduction, not 1:50

Also it was generally believed to be a particular interaction with the previous Orbea Ordu head tube that led to that particularly good result. It wouldn't necessarily work out the same on all bikes.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

Just the CRR. The point of this tool is just order of magnitude estimates. Bro science if you will.

There are too many unknowns with tire aero, and interactions with wheels bike and rider to codify them in any meaningful way.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

So "fancy drivetrain bearings" will save me 9sec/40k, or about 40 seconds over an IM? Really?

I missed out on $750 3 weeks ago due to 41 seconds, so when seconds matter and you are doing everything else you can possibly do, well you start really looking at the little things.

IF you have a disposable income, why aren't you looking at every possible thing that can make you faster?

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-Brad Williams
Website | Twitter: @BW_Tri |Instagram: @BW_Tri | Strava | Co-Founder & Coach at: KIS Coaching
Partnered with: Zoot Sports | Precision Fuel &Hydration | ISM

frictionfacts.com has some good data on this.
but yes, you can save a half watt here, half watt there, but getting top notch bearing setups in your BB, wheels, puleys, and pedals and save a couple watts overall potentially.

SRAM and Shimano 11 speed Ultegra and above all have pretty nice pulley bearings now though, so if you have that already there is not much more to be had from better pulleys.

10 speed ultegra had one crappy pulley that wasted about a half watt

if you are out of low hanging fruit go buy all the frictionfacts reports they are great.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

Yeah, I really need to go online and order 20mm Conti's to go on my H3's instead of the 23mm Michelins before Florida. I'd feel like a dunce missing a PR by a minute or two and not having done it just because I procrastinated.

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I'm beginning to think that we are much more fucked than I thought.

I know Ero has said the Torhans 30 has a 50 gram reduction on a bunch of bike including the IA. A bayonet type front end is helpful since it makes it easier to get the torhans close to the head tube.

They're the only thing left. :(

Because I don't like to enable people who sell worthless junk for high prices, regardless of whether it may have a slight chance of making me faster. If they're proven to be faster, that's a different story. But I'm not going to just throw money at every new thing. Like, for example, those drivetrain coatings you see sometimes (often at IM expos) that are hundreds of dollars? Total scam. My understanding is that ceramic crank bearings are pretty much a scam, but I'm less clear on whether nice wheel and pulley bearings are actually a scam or not.

But jack mentions below that there is some data on my latter point, especially when it comes to swapping older model, but still well maintained, equipment for the newer stuff, so I'll defer to him on that.

Time to shave the beard!

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/kj

http://kjmcawesome.tumblr.com/