Thursday, April 20, 2017

Aero Data: Vittoria Corsa Speed, Contintental GP TT, Continental Supersonic on HED JET+ 6 Black Wheel

Trying to shed some light on tires in the A2 Wind Tunnel
Thank you for everyone that contributed to the GoFundMe campaign to help make this a success!!! Even though we were only at $700 at the time of testing it is clear that people still giving means they value this independent research. It seems like a true watershed moment and I hope others do more more testing in the future. For now, 7 years of good flat karma for those that donated!!!

I have started a Slowtwitch thread for technical discussion of this.

The following is the aero data from the A2 Wind Tunnel on 4/19/2017. I have release just the HED JET+ 6 Black data for simplicity. I also have the Enve 7 SES data that will be coming. This is just aero drag at 30mph and DOES NOT include rolling resistance.

We tested clicnher tires, the 23mm tires (New SS and Vittoria Corsa Speed) at 85psi, the 25mm tire at 81psi, and the 23mm OLD Supersonic, which measures small, at 88psi. Valve extenders was 72mm long. Tires mounted mounted in direction indicated by the manufacturer. Some tires had to be pumped higher initially to get bead to snap and then were deflated and reinflated to proper psi. The little plastic tips on the Conti tires were all plucked off prior to testing although some excess rubber as common with Conti tires is still on the center line. All tires were brand new, purchased by myself from retail stores. The exact same tube was used for all testing.

Click to enlarge

Analysis:

While the Specialized Turbo Cotton had been the top performer for rolling resistance for this style of tire. Recent research by three independent sources has shown that the new Vittoria Corsa Speed is the new top dog by a wide margin. While the Turbo Cotton 24mm has performed terribly from aerodynamic perspective, the Continental Supersonic tire had similar rolling properties but with much better aerodynamics.

The purpose of this test was to investigate the aeroness of this new Vittoria Corsa Speed. Testing showed that it was quite similar to the new 23mm Continental Supersonic. We tested a brand new OLD 23mm Supersonic (measures narrower) and it still performed better aerodynamically but the tire is no longer in production and cannot be easily obtained.

Kool Stop Bead Jack Tool vs Some Tire Levers
Much easier to mount the Vittoria Corsa Speed with this tool 
Regardless the Vittoria Corsa Speed tires present a unique opportunity because it can be run tubeless. Without a tube inside but with sealant. The extra weight of the sealant more than makes up for the weight of the tube but adds the possibilities of significant flat protection.

Unfortunately one draw back of this tire is it is not easy to mount and is significantly tighter than other tires and especially so on these tubeless rims like the HED JET+ and Enve 7. Likely that is by design to prevent high pressure from the tire escaping to the outside. As a result I highly recommend investing in the Kool-Stop bead jack which makes getting these tires on rims much easier. Use of metal tire lever is likely to damage to the carbon rim, don't do it. You also need to invest in a set of tubeless valves, Stan's rim tape, and Orange Seal Tire Sealant. Links below.

Amazon Links: 
Vittoria Corsa Speed Clincher 700x23mm Tubeless Ready Tire
- Continental GP TT 700x25mm Tire
- Kool Stop Bead Jack
- Orange Seal Latex Tire Sealant
- Stans 21mm Yellow Tubeless Rim Tape
- Stans 44mm Tubeless Valve Stem (good for disc wheels but too short for deep wheels)
- Silca Tubeless 80mm Valve Stem (good for deeper wheels)

5 comments:

  1. So - good aero and fantastic crr.

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  2. Hi Thomas,

    How easy is it to flat on these tires? I usually ride GP4KII's, but I'm leaning toward SS 23mm front and GP TT 25mm rear for WI 70.3. Would you advise something with more puncture protection given the road conditions?

    Thanks in advance!

    -Nick

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    Replies
    1. Well the beauty of the Corsa Speed is you can run tubeless with sealant. I don't think any of these tires are that easy to flat. I have worn more Supersonic tires down to the cords than I can count and that says a lot as someone who spent a lot of time training in Tucson with sharp things everywhere on the roads.

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  3. is gp tt a better choice for the front wheel than the gp4000s on a 808fc(non-nsw)

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    Replies
    1. I would go with the 23mm Continental Supersonic on the front personally. The GP4000s would depend on the day, how windy, the average yaw with your own speed.

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