v70cat

Why not 4000s?

TobinH

It's a good tire, and I'm not trying to talk anybody out of them, but I find personally that they are a bit expensive to use a training tire, and I prefer the OCs if I care about speed. I don't want to use one tire all the time, as I want my training tires to be very tough and my racing tires to be very supple.

IronHorseRiderX

Last year I put some 3k miles on Vittoria Open Corsa ( SC and SL variants) and about the same on Veloflex Corsas. Both in 700x23 size.
Went probably thru at least 3 sets of each.
They are nice tires with superb ride.
I switched to 4000S about 2.5k mi ago and could not be happier.
Not a single flat since the switch and they will last another 500 mi or so easily.
I also think they have much better grip, especially in wet conditions.
They do ride harsher but as far as rolling resistance goes they about the same.

chaadster

Anhalt's Crr test results (on the BikeBlather blog) show two sizes of Zipp Tangents, and two versions of Vittoria Evo Open Corsas bettering the GP4kS (if we're just talking about clinchers).

Also, Anhalt's same tests show an 8w variance in power requirements begween latex and butyl tubed GP4kS at 40kph.

Most importantly, I think remembering that Crr numbers are just one facet of tire performance, and not the end-all-be-all, is helpful in deciding which tire is best for any given rider/conditions combo.

No one is challenging the GP4kS as an excellent tire, but there are legitimate reasons for choosing another tire over it.

Dunbar

The Zipp clincher beat out the GP4000S by 1w per pair of tires at 25mph. No real info on how it compares in durability department either. The GP4000S II beats the latest version of the Open Corsa CX III here. It's not a fluke either, the GP4k always tests near the top of the pack. I've never seen 8w saved from tubes although it's theoretically possible if you start with a heavy enough tube. You tend to see a pretty consistent ~2w savings from latex over standard weight butyl and ~1w vs. lighweight butyl across the various roller tests.

chaadster

what does who you know have to do with anything? And what does "I've never seen 8w saved from tubes" mean?

You don't have a legitimate point to make, do you?

RR3

The data I have seen shows 3 watts per wheel advantage for latex over light butyl tube and up to 8 watts over heavy butyl tubes.

Crr on drums is not the real world. Rough roads is a factor that a diamond "smooth" drum model does not take into consideration and tires with better sidewall flexibility and elasticity such as the Vittoria CX or the Compass Extra Legere are noticibly faster and more comfortable on chip seal roads than Continentals.

rpenmanparker 

Unless the cotton is nylon reinforced, I wouldn't have it. I have had too many cotton tubulars asplode on me with the bike just hanging on the hook in my garage to ever ride that crap again. Wolber to be precise.

FIVE ONE SIX

i don't know about that as far as the Cotton's go, because they're still listed on the Specialized website for sale. i will agree that the S-Works Turbo tire with the Gripton is pretty damn good though. i use them, and while i only have about 100 miles on them, they roll great and corner even better! i went from Tubeless IRC Formula Light's (i got tired of getting 1/2 inch gashes on my tires and having to throw away $125 tires after 500 miles cause of it) to the S-Works Turbo's, and i will say they feel pretty damn close to the tubeless IRC's, and they DEFINITELY feel better than the Continental GP4000S's on my other bike. i run the 24's, which really measure 24mm, so the 24's or 26's should be fine. unlike the Continental GP4000sII 25's, which really measure 27mm and were a bit too close for comfort on my 2015 EVO...

a little fyi though, the S-Works Turbo 700x24 is back-ordered at Specialized till the end of July, so if you local LBS doesn't have them they're not going to be able to get them for at least 2 months...

pdedes

life is to short to ride crappy tires. while i love the vittoria open corsa cx, not quite enough durability. but among the best in terms of ride quality. if you get them, they actually benefit from aging for a year in a cool dark place. i love the schwalbe ultremos zx. a bit better in durability than the vittoria, nice in the corners, and a supple enough casing. whatever you do, don't over-inflate your tires. i find the contis need about 5psi less than the schwalbes to get them into their sweet spot (stiffer casing i suspect)

Dunbar

So you quote drum CRR to claim 3-8w advantage of latex tubes and then say we shouldn't believe drum CRR data because it's not realistic? I've seen many drum tests and have never seen anywhere close to 8w for latex tubes. Believe whatever you want but the data is very consistent in the 1-2w range across multiple roller tests. And Jan Heine noted no advantage to latex tubes in his roll down tests.

I get a kick out of people dismissing roller tests as 'unscientific' or not 'real world' enough and then waxing poetic how they just intiutively know their favorite tire is faster than the GP4000S.

Dunbar

I do - it's that all of these attempts to take down the GP4000S as near the top in rolling resistance are futile. The data just ain't there.

RR3

Where did I quote drum data? Where did I say any test was unscientific? If you want that type of data......

Look for the article in 2006 from German Tour Magazine-their data shows that 104gr butyl tubes were 8 watts slower than latex tubes. The difference was 2-3 watts for thin butyl tubes.

Maybe you are right. I am biased. I can't stand that two GP4000S have ruptured sidewalls this year in under 100 miles of riding whereas I went over 9,000 straight miles without a single flat on the same roads riding Challenge PR, Vittoria CX Evo, and Compass EL. Booted tires don't run real well. Continental tires are harsh riding and are junk from my experience. I have 4 of these POS that will go unused, I would not even give them away.

chaadster

No one was trying to do any such thing, but rather calling you out for making false claims.

dglevy

I just looked through this entire thread and was amazed to see that, despite all these opinions, no one cited any scientific studies on the rolling resistance of these tires. Are there none?

For my part, I tried to find studies but only came up with this one, "How much faster are supple tires?" But the article was published by an outfit that was selling its own tires, so would hardly qualify as a disinterested party.

Are we all condemned to opinions without facts on this question?...

tedder

There's been discussion of CRR earlier.

BQ/Compass/Heine obviously have an axe to grind, and they've handwaved over some things, like rotating mass.

Here's a bit of a metastudy:
BEST ROAD BIKE TIRES | In The Know Cycling

Sy Reene

This is more a question out of curiousity, as I don't myself engage in racing or do the Training vs. Racing tire swap out.. but how does someone train on a tire that has different ride characteristics than the tire they'd use in a race? That's to say, if the racing tires have different ride and handling characteristics, isn't it counterproductive to train on a diifferent tire? Ie. how do you get comfortable with understanding limits of the bike/tire in high speed cornering, over cobbles, in wet conditions, etc?

dglevy

Great guns, thanks for the links! (The link to the previous post didn't work but I found it, the discussion starts at comment number 79 , for those who want to find it.)

I will read the meta-study and previous comments with a great deal of interest. This is a real treasure trove of real information. Thanks!