the vittoria tires have shown horrible aerodynamics when tested and are delicate.

this is why they are not favored.

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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

http://www.trainingandracingwithapowermeter.com/...st-results-part.html

I like it...in fact, I've used it as a rear tire for TTs quite a few times. It's decently durable and since I use it in bikes with decent rear tire coverage, I don't think the poor aero is a function of trailing edge aerodynamics.


Too many variables and not enough data. I've always said that if you want to truly know what's best for you, you're going to have to learn how to test some of this stuff yourself. That's why I've explained how I do it...to show it really isn't overly difficult. You just need to be curious.

I hope you also understand how off-putting it is when someone basically says "I don't want to think about this, or put in the work, just tell me what to run." :-/

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http://bikeblather.blogspot.com/

Of course if you don't want to put in the work or think about it, Run Conti attacks, or super sonics, depending on how much you fear flatting.

Can't go too wrong that 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

then the Attack has no testing, just some feedback from users.

I've said all this before, but... I've tested four Attack tires, and have two more I'll test someday. One of them is oddly worse than the GP4000 for Crr, but they other three are good... almost as good as an SS. The Force is good also (tested two of those). The Attack and Force have the same casing, tread compound, and vectran belt as the GP4000 but the tread is quite a bit thinner. So that with the Zipp WT data, and just looking at how nice an Attack looks on a wide rim (IMO), makes it a no-brainer good race tire. Based on SwissSide aero testing regarding the effect of side grooves, I'd turn the Attack backwards so that crosswinds flowing over the top will be more perpendicular to the grooves.

Or pick one of the other good tires. It isn't like it is going to make much difference. I'm pretty certain that sweating GP4000 vs something else should be far down your list of priorities. Us science guys do it because we enjoy splitting hairs. There is no definitive answer because there isn't WT data on every rim and tire and front vs rear.

BTW... manufacturers (particularly Conti) make lots of models in order to increase total sales.

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I have had a Vittoria Open Evo Tri on my rear wheel for about a year of racing.

I have the SS on my bike right now and have been using them as daily drives with great success and no flats. That being said, I have never EVER had a flat time while running Conti 4000's old or new so that piece of mind in a longer race is all I need and of course they test very well. For short races, I run the SS without thinking about it.

If the EVO Tri is more durable than the EVO CX that would be great news. But I don't know what a year of racing means for you. Two ironmans? 5 stage races?

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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

It isn't.

Prob around 600-700 miles (4 70.3, 1 IM, 2 x 40k TT, 2 x 10mi TT, smattering of sprints and olympics). Let's be honest, most people here reading this aren't interested in stage race durability or bike race durability.

I've read more than I would have liked, between books, forums and more... it's whether I understand is another thing... nor enough riding on many different tire brands... It took years just to switch from Michelin Pro tires to GP4000s despite everyone saying they were better, just couldn't believe it until I used them, then it took a while to use latex tubes... I've now used gp4000s and latex for about a year now, just would like some info on getting a marginal gain, since I believe that I'm on the pointy end of aero or crr gains. I've had success with being a fast cyclist for my age, just want to be faster.

Gotcha. I agree, though plenty of people here want to train on their race tires as well, which is madness, but they do.
Plus anyone looking at tubies might care more about durability.

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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

Do you think a heavier rider, like myself, can/should run the attack in the rear? HED says prob not the best choice but seems to be a popular choice on the JET disc of many a fast TT'er.

How bout on a classic p3 with a standard dimpled Zipp 900 tubie?

So I'm unfamiliar with your equations, but my impression is that you just multiply roller Crr by 1.5 to get road Crr. If that's true, how does a smaller roller amplify things more than a larger roller? Otherwise how do you convert from roller Crr to road Crr?

Since this has become a full on is roller testing useful for on road testing thread, I would like to ask has your testing shown that rim width matters? As I recall it has not, yet many manufactures claim that it is a benefit. Are these guys and so many others full of beans?

The smaller the roller diameter, the more the amount of deflection/distortion at the contact patch for a given load, and thus the more power required to turn a given wheel speed.

Roller to flat math is outlined here: http://bikeblather.blogspot.com/...on-rollers-math.html

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http://bikeblather.blogspot.com/

I have not found any differences (within the error of the measurements) for a given tire between testing on a narrow Velocity Deep V rim and a Zipp 101 (at the same pressure). Theoretically, there may be a gain, but I think the amount must be too small to matter appreciably.

If anything, some folks may have found themselves faster due to the emergence of wide rims encouraging them not to over-inflate their tires ;-)

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http://bikeblather.blogspot.com/

finally got around to verifying on zipp website, but 130 psi exceeds their max rating for their CC wheels(808 and super 9 anyway)

They don't allow 20mm tires either, do they?

haven't read anything that specified that, you may be referring to hed

You just killed the complete "as a service" industry with 1 quote. Brilliant ;) I smell a good business-concept for you.

But I do understand you point of view since, as you repeatedly state: A lot of variables of which a number of these are personal / linked to gear used.

Tom's Pharmacy: This is exactly what Josh found out by doing what he did when working with the different Pro-teams on the Roubaix setup. I can't imagine the real-life cost (labor/travel/gear) that went into finding all these parameters and repeatedly have the pro-riders test it. A wealth of data, and only generically applicable to "average Joe" trying to ride on cobbles. I don't know if you have read his blog / journal on his site, but surely worth your time.

I would say that for Triathlon it is slightly easier (cobbles are way less forgiving then road-surfaces) but still, to get the real optimal solution: Go out and test it as much as you can. I you are worried about the few grams of aero drag, train a bit harder/better/smarter and play it safe :D

I am very happy with the Spec's Turbo Cotton 24's open my Zipp 808-FC's in my P5 with Vitoria Latex tubes at 95PSI (inflated with a Silca pump). I'm 179cm, 69kg. So that is your n=1 experience. Change any of these 7 parameters and the outcome might be totally different... I only have that new pump 2 weeks and I noticed I had to drop from 100 -> 95 to get the same feel from the tires. probably, so make sure your pump is a good one. Yes, you might think, it's only 5 psi, but at the top-end of your range (for practicality let's say most of us typically inflate between 90 - 110PSI) , that is a very large and noticeable difference.

All the best,

S.