I bought Conti GP4000S II last year because they came highly recommended. I used them exclusively for training and racing and absolutely loved them. I was interested in checking out faster options for this season but the only data I have seen combining rolling resistance with aero data shows me that they are still among the fastest tires. I sure don't see anything in Tom A's study suggesting that a Specialized Turbo Cotton is faster. Also, somewhat irrationally, my former experience riding Michelin is that they are a pain to mount and high end Vittorias puncture if you look at them funny.

Perhaps you could link to some data showing the TC or the Michelin being 4w-5w faster in rolling resistance and aerodynamics before claiming that they outperform the GP4000S II? Without that, it seems like the simple answer to your question is "because they are the fastest all around tire and cost 1/3 of the other options".

I own 2 LBS's. I hate GP4000's cuz they are online for 35 bucks and because they are the best tire in the world. Turbo Cottons are marginally faster, and I dare say they ride better, but the GP 4000 lasts WAY longer.

Well, if you go to the Flo interactive page, and look at the 23C GP4KS vs. 24C Turbo cotton, in the combined aero+rolling resistance chart, the TC beats the GP4KS out to 7.5deg of yaw. It's only at 10deg of yaw and above that the GP4KS wins out on that particular rim (because the rim was designed around that particular tire).


http://flocycling.com/aero_tire_power.php

On another rim, that most likely won't be the case...AND, as I've said many times, low Crr makes up for a LOT of "aero sins".

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http://bikeblather.blogspot.com/

the Michelin Pro2Race was the best _feeling_, fastest rolling tire at the time with marginally ok durability. when they moved manufacturing to the far east(thailand?) for the pro3, quality dropped through the floor - they'd cut/flat/tear if you looked at them sideways. the EVO cx's never felt fast, like the tread was too sticky/thick and durability was also not great. i had used the attack/force combo, but the front was too fragile for me, despite being measurably faster.

the gp4k-S2 was not great on durability when it came out, but the quality has returned.

here and there i've tried schwalbe, Kenda, IRC, CST, maxxis, panaracer, and some crazy budget stuff, but always come back to the gp4k.

for me, flat-resistance is paramount, with cornering grip and durability coming in next. that they feel fast is a nice bonus.
gatorskins(pre hardshell which i have not tried yet) are slow and feel slow compared to the gp4k.

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"...I try not to ever ride as slow as 20mph. ;) ... And even more than that, I don't race with a speedometer. My computer is set up to show Power // Cadence // Time. I don't actually ever know how fast I'm going. I only know that if I'm in 53/11, and it takes more than 100rpm to hit my target watts, it's time to coast." - Jordan Rapp on '09 IMC

None of these guys even know latex tubes still exist. They are all on butyl, they're not even tubeless.

Fwiw regarding the 23c... one guy brags about how he can hit a 90 degree bend at 30mph. But that's n=1

<shakes head>

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http://bikeblather.blogspot.com/

What's the flat resistance of the Supersonic?

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'It never gets easier, you just get crazier.'

Relative to a GP SS or TT? And what about aerodynamics? Bicyclerollingresistance tested this tire tubeless with 20g of sealant. They said add 1.5-2w if you use a latex tube. That would put it almost dead even with the 25mm GP TT and in theory the SS should be slightly better.

Any rule of thumb/order of magnitude for this?

Ie. Could tyre size/shape & rim interaction aerodynamics be considered basically negligible (<1w), with Crr being the dominant driver of tyre choice?

He says that...but his own data on the subject shows no difference at road bike pressures, which matches my own experience. Multiple times I've run tubeless tires w/latex tube first and then tubeless, with no measurable difference in Crr.

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http://bikeblather.blogspot.com/

Good enough for my purposes...I've never flatted one, in fact <knocks wood>

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http://bikeblather.blogspot.com/

Not that simple. It depends on a multitude of factors, such as the particular aerodynamics of the wheel tire combo, the expected speed, the expected wind angles, rider+bike weight, etc...

But, I guess I could boil it down to "run the lowest Crr tire you can that meets Josh's 105% width ROT, and that you are comfortable with the durability."

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http://bikeblather.blogspot.com/

Well, so far the follow-up "Which Conti Tyre" poll has the GP4000S II at 70%.
Combined with a 71% result for Conti in the original "Which Tyre Brand" poll, that means the Conti GP4000S II is the main tyre used by 50% of all Slowtwitch poll respondents.

Dan, your new poll doesn't let me answer! If it is my race setup you are interested in, I ride different Conti tyres front and back.

Whilst I am in that 2% for Zipp (I race on the SLSpeed tubs), my go-to for clinchers is also Continental. I have GP4Ks2 on my training wheels, and if and when I move to new carbon (clincher) race wheels, I would probably plump for the GP TT. For me they also tick that 'proven' box for clinchers, but for Tubs not so much.

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29 years and counting

I want to buy Specialized Cotton turbos...but to do so, I'd have to go 15km out of my way.

Conti GP4000IIs...stocked in my LBS of choice, cheap(enough) good(enough). Lazy consumer. But...latex tubes really transform these tires into something very sweet indeed!

I see the new poll is following a similar trend with 71% choosing the GP4000S II.

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Favorite Gear: Dimond | Cadex | Desoto Sport | Hoka One One

Where are you located? I just bought a pair of TCs online directly through the Specialzed website. Arrived at my house 2 days later. I'm in the US though...

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http://bikeblather.blogspot.com/

I will jump in on that.

I crit race and TT on the 23c Corsa Speed run tubeless on light-bicycle tubeless rims(45mm crit and 90mm with a whee cover for TT).

I have never flatted one of these tires and trust the data that shows them to be fast. Set up tubeless they are really hard to beat. Matched with a $600-$700 wheelset, they are even better!

I road race on the Victoria Corsa graphene tires in 25c on Enve 6.7s with latex tubes and orange seal. Our road race courses have plenty of gravel sections and they have never flagged. In fact, I train on these and get over 2000 miles before they need a replacement.

Also use schwalbe one 30c tires on my grave bike tubeless at low pressures. It's amazing how versatile his setup has shown to be.

"Dan, your new poll doesn't let me answer! If it is my race setup you are interested in, I ride different Conti tyres front and back."

the next poll will drill down on this. that's now i started this poll, but it quickly got out of hand. do you ride 4000S II in 23mm, 25mm, or 28mm? do you run 23mm in front and 25mm in back, or twin 25mm, or twin 23mm, or is there a 28mm in all of that? one poll just sucks up that tire. so i had to split these polls into smaller chunks.

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Dan Empfield
aka Slowman

wait, what? :)

no supersonic and in 20? :)

Will these plugs survive road tyre pressures? These things are magic on the MTB (so much that on local rides I don't take a spare tube) but A) Can they survive road pressures, and B) Can they fix a tyre that's already mostly deflated? Part of why they work on the MTB is ease of insertion into a tyre that still very much has it's shape.

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ZONE3 - We Last Longer

I'll let you know...I first experimented with this technique just by poking a small piece of t-shirt into the the ~2mm wide hole I got on a road tubeless tire that the sealant was having a hard time keeping totally sealed. I was just using the end of a spoke at that time, not the dedicated tool, and it seems to have worked fine. The cotton soaked up the remaining sealant inside the tire and I trimmed off the cotton sticking out of the tire. So far that's held...oh, and then I had to go about the crappy job of removing dried up sealant that had spray-coated the entire rear triangle of my bike when the puncture happened :-/

I just received a package with a couple of the GI kits yesterday. I plan on playing with both the supplied cords and some butcher's twine to see how it goes. Based on how well the little swatch of T-shirt poked in the hole worked, I have high hopes for both the dedicated cords and/or the cotton twine. The key piece to have IMO is most likely the small tool ;-)

It seems to me that even with the tire fairly deflated, it should be possible to still plug it this way. If you're running sealant in it anyway, the beads will be fairly "locked in" by dried up sealant along the edges, so I don't think I'd worry about the having to reseat the bead.

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http://bikeblather.blogspot.com/

Why no conti supersonic option in your current tire poll?

Lots of triathletes race on those ...
(including myself)

So I just had to pick 'other' ...

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Advanced Aero TopTube Storage for Road, Gravel, & Tri...ZeroSlip & Direct-mount, made in the USA.
DarkSpeedWorks.com.....Reviews.....Insta.....Facebook
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I've been looking for a kit like this. I need it for my fatbike adventures. For my fatbike tire/rim combo, they snap on there so tight, I'm not sure if I'd be able to get the bead off trail side in the cold. Thanks for posting that!

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