Based on AFMs testing, about in the range of the Challenge Forte clincher and the Bonty AW19, or slightly worse...


Ummm...I didn't have one handy?

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http://bikeblather.blogspot.com/

Sure. How about this?

Life is too short to run crappy rolling tires, and look! You too can figure out which is which ;-)

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http://bikeblather.blogspot.com/

The 4000GPS was tested in the original post. He found a road Crr of 0.0038, which would translate to about 35 watts @ 40 kph on Tom's graph.

Do you have any idea where the conti GP 4000s would fit into your graph?

I tested another one that was well worn, and it did a little better than the first... which is quite good considering what kind of tire it is.

But I also have another (newer) Attack that is at the other end of the spectrum (Crr> .004 on my chart). It's built like a GP4000S only with thinner tread. That one really has me baffled. Maybe the tread compound is different or something...

I've also tested 5 20mm Supersonics. All were very good... some a little better than others. The newness and tread wear didn't seem to matter.

Ok, thanks for very much for the great info and insight into tires! For me the GP 4000s will be perfect for most of my road racing and training. I'll switch to supersonics or vittoria evo triathlon for my TT events. Cheers

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"I swim because that's how I get to ride my bike."

Are there any know problems with Continental GP Supersonic availability? My guy says only 7 left in the US and thinks they are being discontinued.

Probably because you can buy them retail overseas for less than US wholesale. But that's true of a lot of tires. If Conti quits making them, I'll be mildly upset. It's the only good 20mm tire I know of.

What's the final verdict?

Convince everyone you want to beat to use slow tires with liners and thick tubes... to prevent flats... because, you know... there is *nothing* worse than getting a flat in a race. And one tire isn't really faster than another. All this tire rolling resistance BS is a bunch of hype.

I've been in a number of plants that make car parts using rubber, seals, mounts etc. Its amazing how much goes into formulating and forming the rubber itself and a lot the materials are natural products.

It wouldn't surprise me a bit if some of the difference is batch to batch variation of the rubber. I also wonder if some of the lore of aging tires might not be true. Tires outgas for quite some time and many rubber compounds will continue to cross link for quite a bit of time. Some variation may come form age.

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Styrrell

haha thank you for entertaining me, I had some more time to read through...

GP4000S for training, Open Corsa SL for racing.


Thank you for the time you lads put into this, it's quite valuable and I greatly appreciate it!

MTM,

Josh also posted once a curve comparing different tires on the 303 Firecrest carbon clincher, on that graph the narrower Conti Attack would make the wheel stall earlier than the wider GP4000S would.

So I guess it is a case to case basis, hard to make a general rule, don't you think ?

As for the 23mm Supersonic, taking into account that is is quite narrow (width similar to 22mm Attach) for a 23mm and that it is quite faster than the 20mm Supersonic, I think it is a good match for the wider rims we use these days. Though not a concern for some, we need to keep in mind also that a 20mm tire doesn't fit as securely on a rim with hook to hook width of 16mm and more then a 22-23mm tire would... but experience is best in that case and I haven't used any narrow tire on my firecrest wheels so can't tell for sure.

I think the 'crushing' part was mostly the significantly higher stall angle? I don't recall exactly, but I remember Josh and/or Rapp said the new 808FC (the older 808 was tested) would be even better then the Stinger tested and at least from Zipp's own graphs the 808FC is only significantly better past 10 degrees because of a higher stall angle.

I have both had a 20mm and a 23mm mounted on my Jet Disc C2, which I think is more or less the same rim as the other Jet C2 rims. The 23mm has a little bit of bulb shape, though not very much IIRC. The 20mm is even narrower than the brake tracks.

I recall those graphs and found them:

http://www.carbonconnection.com/product_images/uploaded_images/303-drag-chart.png
http://i41.tinypic.com/2lmnc54.png


Not that much difference between the stall angles, but sure, there is a little. Attack and GP4000S perhaps also have different shapes, so really hard to judge the two graphs from only the tire widths.


A more interesting thing is perhaps to compare 23mm vs. 25mm GP4000S. Eyeballing it there seems to be 10-15g of extra aerodynamic drag from 0-10 degrees or roughly 1-2W. If it is the same difference between 20mm and 23mm SuperSonic it is not impossible the better Crr of the 23mm could more than make up for it. Best (only?) way is probably for me to try and do some field testing on it and see if I can tease out any difference.


Narrow tires and wide rims could indeed cause problems (more of a problem with silk-based tires I have heard). I have used 20mm SuperSonic on both Jet Disc C2 and Jet 6 C2 without problems, though. But I know Carl Matson from Trek is strongly discouraging using 20mm tires on the new wider rims.

No what we've seen Tom's results on the Vittoria, we need to check the 2013 Vittoria Open Corsa SL, two main changes : it is now a 22 (used to be a 23) and it has Isogrip. If rolling resistance is still good, aero slightly better from the change in width and grip better with Isogrip it could be the kind of tire we are all looking for (the triathlon 22 is quite good but lacks the grip of Isogrip) ;-) .

Vittoria website : http://www.vittoria.com/...-tires/#product-4486

New specs :


28"22-622 700x22c 210gr product code : 111.360.SC.22.111BX
Open Corsa SL - Technical table

Looks interesting. I've had bad experiences with Vittoria Corsa tires, though. They're very good on dry roads, but I have found them lethal on wet roads. They simply lose grip early and suddenly. Maybe that's something they have tried to change with Isogrip?

Edit: Also, usually the Vittoria Corsa tires don't do too well aerodynamically. I don't know if the Triathlon is any better.

Do you know which model year the new Attack you have tested is? I know they have upgraded the Attack/Force for 2013 so it has a lower weight and perhaps then also different (better?) Crr.

I bought the slow Attack last summer. The fast one a couple years ago at least.

If you're referring to CX models, I have to say that I personally don't like the CX treads...neither the compound, nor the "file tread" on the sides. Both seem to me to make that tire a less than stellar cornering choice.

The SL type tread, along with what appear to be the predeccessors (i.e. the Bontrager RXL Pro Open, and the S-Works Mondo Open) isn't like that IME.

BTW, I thought that the 23C SLs I bought have the "isogrip" nomenclature on them. I'll check later...

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http://bikeblather.blogspot.com/

Yes, I have only tried the CX models - both in 290 and 320 TPI. They are scary on wet roads.

Is the SL another thread compound or the same but with a slick thread? Also, does it have the same ridge on the sides like the CX? Same question for the Triathlon.... I'm thinking that might contribute to the below par aerodynamics.

The Triathlon has a slick center and "roughened" side tread. There is a lip where the tread meets the sidewall. I don't know of any "open tubular" (glued on tread) tire that does not have this. The tire is otherwise very smooth though, unlike molded tires that tend to have a lot of small ridges and bits sticking out.

Would love to see some up to date CRR data on the Conti GrandPrix TT clincher and Conti podium TT tub tires?

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If you are sure you will fail, or convinced you will succeed, you are probably right.....

did i just get a couple of the wrong size tires???!!! 20vs23 SS

what is the weight of the ss 23 in real life vs the SS 20 ?

the SS23 must be extremely thin compared to the SS20

on contis site the difference is only stated as 5 gram...

but some other people are taking 137 and 140 for the SS20 ....

My 20 ss is 135g.
My 23 ss is 160g.

I don't know which size you got, but after thinking some more about it the 23mm will probably have a hard time being faster on the front. The Crr difference seems to be ~1W for one wheel, which is probably less than the aerodynamic difference between the sizes, at least if looking at some of the Zipp graphs for the 303FC. Of course, we don't know exactly how 20mm vs. 23mm do aerodynamically on something like a 808FC or Jet 9 C2.

may have to ship wheel to tunnel with buddy so he can check :)