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Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [milesthedog] [ In reply to ]
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So Specialized finally figured out how to make a brake track that doesn't dissolve down a good descent-make a disc wheel.
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [milesthedog] [ In reply to ]
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Development notes: Specialized developed the CLX50 around a 24mm wide (spec) tire which measured 26mm when mounted. It appears they developed the rim around their own 24mm S-Works Turbo/Turbo Cotton casing. What's interesting is that they have a graph showing rotational+translational drag.

My thoughts:
-The 454 NSW certainly doesn't seem to bring anything game-changing to the party. IMO it better really be 303 stable if Zipp wants to justify its existence.
-I wonder how much better the Zipp wheels would have tested with a 23mm GP4000 SII? That seems to unofficially be Zipp's go-to tire.
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [GreenPlease] [ In reply to ]
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they would be better with a supersonic tire

looks like power to spin is negative from the unlabeled graphs
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [milesthedog] [ In reply to ]
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Too bad they didn't publish rotational drag. It would be interesting to see if the study on JackMotts site reported similar values.

Also, as I read this it looks like they were designed around the Specialzed Turbo tire, but it doesn't talk about the Turbo Cotton.
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [grumpier.mike] [ In reply to ]
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They tested with a 24mm Turbo Cotton
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [GreenPlease] [ In reply to ]
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GreenPlease wrote:
They tested with a 24mm Turbo Cotton

Nope, they were tested with their Turbo tire:

"Win Tunnel testing were all done around a Specialized S-Works Turbo 24c tire (measuring ~26mm wide)"

It's nice that they included rotational drag, but then they go and mess up the axis (and I would like to hear how they measured the rotational drag, by the way). Why include units on the axis if you are not even going to put numbers on it?
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [MTM] [ In reply to ]
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Ah, thanks. I could have sworn they said Turbo Cotton somewhere in there.
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [milesthedog] [ In reply to ]
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Would rotational drag vary much between wheels of of the same rim depth? I imagine that the rotational drag is largely driven by spoke choice, and since there are so few choices when it comes to aero spokes it seems like they would all be very similar.
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [GreenPlease] [ In reply to ]
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GreenPlease wrote:
Ah, thanks. I could have sworn they said Turbo Cotton somewhere in there.

They did.


"The same tire and pressure was used for all testing – a Specialized Turbo Cotton 24c @ 100psi. (Actual measured width is noted in the graph)"




Confusing. Early on they claim they designed to tire around the Turbo S-Works Turbo 24c, but then they publish competitive test results using the Turbo Cotton 24c. Perhaps the performance delta to Zipp was less impressive on the S-Works Turbo?

"They're made of latex, not nitroglycerin"
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [gary p] [ In reply to ]
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I'm pretty sure the two tires are dimensionally identical.
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [gary p] [ In reply to ]
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Perhaps. This paper seems like it was done in a bit too much of a rush without proper review (mentioning different tires, no numbers on the axis).
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [GreenPlease] [ In reply to ]
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GreenPlease wrote:
I'm pretty sure the two tires are dimensionally identical.

I don't think so. IIRC, if you look at Tom A's wind tunnel data you will see that the Turbo tire is much more aero than the Turbo Cotton tire. I believe the manufacturing methods are different (with the Turbo Cotton being a "open tubular", whereas the Turbo is not).

From the graphs it actually does look more like it's the Turbo Cotton being used, since the drag is not decreasing much at yaw - which it usually is with a more aero tire.
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [GreenPlease] [ In reply to ]
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GreenPlease wrote:
I'm pretty sure the two tires are dimensionally identical.

They may have similar nominal specs, but the construction of the two is quite different and they presumably shape differently when inflated to the same pressure.

Tom Anhalt wind tunnel tested both (along with various other sized Specialized tires) on the same wheel (CLX64) and found considerably different behavior at yaw angles beyond 5*.

"They're made of latex, not nitroglycerin"
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [MTM] [ In reply to ]
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MTM wrote:
GreenPlease wrote:
They tested with a 24mm Turbo Cotton


Nope, they were tested with their Turbo tire:

"Win Tunnel testing were all done around a Specialized S-Works Turbo 24c tire (measuring ~26mm wide)"

It's nice that they included rotational drag, but then they go and mess up the axis (and I would like to hear how they measured the rotational drag, by the way). Why include units on the axis if you are not even going to put numbers on it?


Actually, it says they designed around the S-Works Turbo, but the testing was with a Turbo Cotton.

I'm dismayed by the lack of units on the charts...at least tell us what each division represents. Otherwise, there's no way of knowing if we're looking at small or large differences :-/

Are the quoted wheelset weights with, or without braking discs attached to the disc models? My bet is "without", based on the Enve and Bontrager weights. If that's the case, then this is the second example of the wishful thinking about disc rims being able to be lightened enough to overcome the weight hit of de-integrating the braking surface not coming true...

I'd also like some more information about the "rotational drag" and how that was measured, and then "translated" back into an equivalent CdA. Is it possible the "translational" and "combined" values are just the drag measurements from wheel-stationary and wheel spinning measurements? If so, then that's still missing the "power to rotate" contribution.

I DO like the fact that they do what they can to increase spoke bracing angle. Even small changes in that can have relatively large lateral stiffness effects. Damon Rinard found that out a long time ago when he looked at the lateral stiffness of a radially laced wheel, where the only change was a "spoke heads out" vs "spoke heads in" configuration in the lacing :-)

http://bikeblather.blogspot.com/
Last edited by: Tom A.: Jan 13, 17 8:33
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [GreenPlease] [ In reply to ]
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GreenPlease wrote:
I'm pretty sure the two tires are dimensionally identical.

They aren't...just because of the construction. There's a "lip" on the TC where the tread is glued to the casing that's not present on the Turbo

http://bikeblather.blogspot.com/
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [Tom A.] [ In reply to ]
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Tom A. wrote:
MTM wrote:
GreenPlease wrote:
They tested with a 24mm Turbo Cotton


Nope, they were tested with their Turbo tire:

"Win Tunnel testing were all done around a Specialized S-Works Turbo 24c tire (measuring ~26mm wide)"

It's nice that they included rotational drag, but then they go and mess up the axis (and I would like to hear how they measured the rotational drag, by the way). Why include units on the axis if you are not even going to put numbers on it?


Actually, it says they designed around the S-Works Turbo, but the testing was with a Turbo Cotton.

I'm dismayed by the lack of units on the charts...at least tell us what each division represents. Otherwise, there's no way of knowing if we're looking at small or large differences :-/

I see that now. Confusing. Smells a bit like the Turbo Cotton gave better results compared to Zipp (like mentioned above). Why else not use the tire you designed around? (Maybe they should have designed around the Turbo Cotton in the first place, but that's another thing).

Yes, at least give us numbers for the divisions. I can see Mr. Yu cringe as he saw what the marketing department ended up with for a final release of this paper :p
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [MTM] [ In reply to ]
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MTM wrote:
GreenPlease wrote:
I'm pretty sure the two tires are dimensionally identical.


IIRC, if you look at Tom A's wind tunnel data you will see that the Turbo tire is much more aero than the Turbo Cotton tire.

It was a much more aero tire on that wheel. It may or may not be the same on a different wheel.

"They're made of latex, not nitroglycerin"
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [Tom A.] [ In reply to ]
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Tom A. wrote:
GreenPlease wrote:
I'm pretty sure the two tires are dimensionally identical.


They aren't...just because of the construction. There's a "lip" on the TC where the tread is glued to the casing that's not present on the Turbo

Ah, gotcha. I wonder how it would have fared with the 24mm Force. That seems to be like a really good bet on the new generation of ultra-wide wheels.
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [gary p] [ In reply to ]
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gary p wrote:
MTM wrote:
GreenPlease wrote:
I'm pretty sure the two tires are dimensionally identical.


IIRC, if you look at Tom A's wind tunnel data you will see that the Turbo tire is much more aero than the Turbo Cotton tire.


It was a much more aero tire on that wheel. It may or may not be the same on a different wheel.


True. But judging by how all "open tubulars" seem to do in aero testing (i.e., early stall), I wouldn't bet too much money on the Turbo Cotton being an *aerodynamically* good choice on any wheel.
Last edited by: MTM: Jan 13, 17 8:49
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [GreenPlease] [ In reply to ]
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GreenPlease wrote:
Tom A. wrote:
GreenPlease wrote:
I'm pretty sure the two tires are dimensionally identical.


They aren't...just because of the construction. There's a "lip" on the TC where the tread is glued to the casing that's not present on the Turbo

Ah, gotcha. I wonder how it would have fared with the 24mm Force. That seems to be like a really good bet on the new generation of ultra-wide wheels.

Yeah...but they're not likely to show data of their wheels with other brands of tires ;-)

http://bikeblather.blogspot.com/
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [MTM] [ In reply to ]
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MTM wrote:
gary p wrote:
MTM wrote:
GreenPlease wrote:
I'm pretty sure the two tires are dimensionally identical.


IIRC, if you look at Tom A's wind tunnel data you will see that the Turbo tire is much more aero than the Turbo Cotton tire.


It was a much more aero tire on that wheel. It may or may not be the same on a different wheel.


True. But judging by how all "open tubulars" seem to do in aero testing (i.e., early stall), I wouldn't bet too much money on the Turbo Cotton being an *aerodynamically* good choice on any wheel.

You're probably right. But, as Tom says, "low Crr can make up for a lot of aero sins" ;).

"They're made of latex, not nitroglycerin"
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [MTM] [ In reply to ]
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MTM wrote:
Tom A. wrote:
MTM wrote:
GreenPlease wrote:
They tested with a 24mm Turbo Cotton


Nope, they were tested with their Turbo tire:

"Win Tunnel testing were all done around a Specialized S-Works Turbo 24c tire (measuring ~26mm wide)"

It's nice that they included rotational drag, but then they go and mess up the axis (and I would like to hear how they measured the rotational drag, by the way). Why include units on the axis if you are not even going to put numbers on it?


Actually, it says they designed around the S-Works Turbo, but the testing was with a Turbo Cotton.

I'm dismayed by the lack of units on the charts...at least tell us what each division represents. Otherwise, there's no way of knowing if we're looking at small or large differences :-/

I see that now. Confusing. Smells a bit like the Turbo Cotton gave better results compared to Zipp (like mentioned above). Why else not use the tire you designed around? (Maybe they should have designed around the Turbo Cotton in the first place, but that's another thing).

Yes, at least give us numbers for the divisions. I can see Mr. Yu cringe as he saw what the marketing department ended up with for a final release of this paper :p

That's Dr. Yu now ;-)

Here's the thing about Turbo vs Turbo Cotton...as we've seen, the much lower Crr of the TC tends to make that a faster choice overall, especially for racing. I have no problem with them using that for the aero testing, since that's the most likely choice for a racer to use...AND it more closely represents their fastest tubular tire offering as well.

In other words, don't get caught up in chasing high yaw angle performance of tires that aren't as low of a Crr...that's not "keeping your eye on the ball", so to speak.

http://bikeblather.blogspot.com/
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [gary p] [ In reply to ]
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gary p wrote:
MTM wrote:
gary p wrote:
MTM wrote:
GreenPlease wrote:
I'm pretty sure the two tires are dimensionally identical.


IIRC, if you look at Tom A's wind tunnel data you will see that the Turbo tire is much more aero than the Turbo Cotton tire.


It was a much more aero tire on that wheel. It may or may not be the same on a different wheel.


True. But judging by how all "open tubulars" seem to do in aero testing (i.e., early stall), I wouldn't bet too much money on the Turbo Cotton being an *aerodynamically* good choice on any wheel.

You're probably right. But, as Tom says, "low Crr can make up for a lot of aero sins" ;).

Yep, it's probably still the faster of those two tires on most/all wheels when taking Crr into account :)
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Re: Specialized Roval CLX white paper: more aero than Zipp NSW, lighter than Enve [Tom A.] [ In reply to ]
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Tom A. wrote:
MTM wrote:
Tom A. wrote:
MTM wrote:
GreenPlease wrote:
They tested with a 24mm Turbo Cotton


Nope, they were tested with their Turbo tire:

"Win Tunnel testing were all done around a Specialized S-Works Turbo 24c tire (measuring ~26mm wide)"

It's nice that they included rotational drag, but then they go and mess up the axis (and I would like to hear how they measured the rotational drag, by the way). Why include units on the axis if you are not even going to put numbers on it?


Actually, it says they designed around the S-Works Turbo, but the testing was with a Turbo Cotton.

I'm dismayed by the lack of units on the charts...at least tell us what each division represents. Otherwise, there's no way of knowing if we're looking at small or large differences :-/


I see that now. Confusing. Smells a bit like the Turbo Cotton gave better results compared to Zipp (like mentioned above). Why else not use the tire you designed around? (Maybe they should have designed around the Turbo Cotton in the first place, but that's another thing).

Yes, at least give us numbers for the divisions. I can see Mr. Yu cringe as he saw what the marketing department ended up with for a final release of this paper :p


That's Dr. Yu now ;-)

Here's the thing about Turbo vs Turbo Cotton...as we've seen, the much lower Crr of the TC tends to make that a faster choice overall, especially for racing. I have no problem with them using that for the aero testing, since that's the most likely choice for a racer to use...AND it more closely represents their fastest tubular tire offering as well.

In other words, don't get caught up in chasing high yaw angle performance of tires that aren't as low of a Crr...that's not "keeping your eye on the ball", so to speak.


Him being a Dr. just make me think he cringes even more ;)

I know, the TC is most likely the faster tire in most circumstances. Which is why they perhaps should have designed around that. But then the graphs don't come out as nice! So you got to figure out if you want to go fast or look fast (lucky for me a lot seem to go for the latter! ;) ).
Last edited by: MTM: Jan 13, 17 9:09
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