We were most competitive with the deeper section wheels at nominal yaw angles (read 0-10/12.5). After looking back through our numbers, we yielded a time-weighted drag advantage over the 858 and jet9 of a few grams...a win is a win I guess (Tom Brady included).

Now, having said that, it brings back the entire high-yaw discussion Dan alluded to in his original post. We did not (but plan on doing so in the future) measure side force, although all riding reviews and first hand rides, lead to riders claiming incredible side wind performance. Our first real test ride of these was way back in December of 2015 on A1A in Miami, and Marty definitely was blown away with their performance. So the deep section 858s and Jet9s are giving you better drag performance at high yaw, but at the same time, blowing you all over the road. So which is more valuable in a high yaw situation to you?> It's a personal preference thing at that point...

Last, found this while digging through some documents which may be helpful in explaining my earlier post about stress migration:

All makes sense. What others may be suggesting though is that since are trying to be totally transparent, why not include those numbers from the Jet 9 and 858 in the nonweighted chart it Or take them out of the weighted drag analysis. But you can’t really have it both ways as it looks like you aren’t being transparent. I mean, they are deeper, so you wouldn’t expect the 6560 win at higher yaw. Your reasoning behind why the “better” wind tunnel performance of the 858 and Jet 9 has little applicability in the real world is sound—lay it out there.

[/url]Another set of wheels and another dream of going in to cycling industry….

What is more important for people to understand is the fact that we are talking about 9g of drag at 30mph. This equals to about 1W

If you can hold 48km/h (410w!) for 180km (3 hours and 45min) you would save 11 seconds
http://www.aeroweenie.com/calc.html

I do not have details about measuring equipment at the A2 but 1W at 410W could be outside of margin of error of the measuring devices in that tunnel. 0.25% that’s is quite impressive precision. I wonder if they repeat each test 3 times what numbers we would get, exactly the same, I doubt it...

“Not only does that mean that WAKE 6560 distanced itself from Zipp 404, and HED Jet 6+, but it also surpassed Zipp 454, 858, and HED Jet 9+.”

When normal person reads above, it might think 5-10% better maybe event 15% surly not 0.25%

Competition is awesome and needed, but when looking at the data I would actually get Hed Jet 6+ for 900$ set instead of paying 2400$ for 1W savings with WEAK 6560

Given the price point HED is the CLEAR winner in this test and they almost always are. Maybe HED (or Flo) should make a weighted drag to price point graph to show just how far ahead of the competition it really is.

Can you show the weighting used for the time-weighted drag?

I don't see that in the blog posts, just a link to the ST article that shows multiple yaw angle probability histograms. As we've seen with the Hambini, et al, posts, that input can matter quite a bit when trying to distill performance down to a single number ;-)

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http://bikeblather.blogspot.com/

i think what everyone is missing with this wheel, just like with the 858, is it’s cross wind stability.

with my 88 front in a crosswind i get blown all over the road, and it’s not a pleasant riding experience. on a rented 858 i could hardly feel any sort of crosswind, the wheel just felt like it shredded it.

of the princeton will is even on par with all the competitors and eliminates cross wind issues, to me it’s a win.

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80/20 Endurance Ambassador

No we get that. That isn’t lost on us at all. It’s a great selling point...And they should continue to beat that drum...But, Better stability than HED 6? Enve 5.6? Roval 64? Impossible to quantify...,but what can be quantified has been manipulated which is our current focus—I’m not saying some other wheel (or bike) companies don’t do the same thing but PC is preaching transparency so let’s have it. They have said we can ask anything-literally anything....so, we are.

We used FLO's weighting method for drag, you can find that here:


http://flocycling.blogspot.com/2016/03/flo-cycling-wheel-design-series-step-2.html

Attached you will find a yaw chart including 858 and 9+.

Also the curves are "smoothed" as a visual setting.

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Paul Daniels
paul@princetoncarbon.com
http://www.princetoncarbon.com

Thanks for that Paul. We understand there are likely more aerodynamic possibilities for wheels out there, but the goal of the 6560 remains the same: the fastest overall wheel system for a variety of conditions.

This allows the rider ONE wheelset to train on, climb on, tour on, ride gravel and race on. They were good enough for Wurf, so I would hope they are good enough for everyone here.

So, if it replaces your deep section, short climb, and mid-section wheels with one solution, is price point that extreme?

We are a young and eager company and hoping we can get more riders demoing these wheels to really feel why everyone that has ridden them has bought a set.

I have a hard time believing that the 858 blows you all over the road to the same extent a Jet 9 does. If that's the case, doesn't that discredit the principle of the design? What sort of simulations/studies have you done on how the center of pressure changes with a change in yaw angle?

Maybe I'm overlooking something obvious, but I don't see anything there. I looked in "About", "News," and on the wheel product pages, "More Information, "Description."

Not seeing anything.

As an engineer, I prefer the term "evidence" to "truth." But maybe I'm missing the data that includes the 858 or other fast ~80mm-type wheels, like Jet 9+ or Enve 7.8. The graph in this thread only includes the "mid-depth" wheels like 404. Which is fine since the 6560 falls into the mid-depth category, broadly speaking. But if you're going to make the claim of being the aerodynamically faster than the deeper class of wheels, then I think evidence should be presented. I could be just missing it on your Web site, as MTM seems to claim it's there. But I'm just not finding it.

Edit: OK, found it in the attachment right before my post, and from @DFW_Tri's indication. Yeah, making people dig through like 2 pages of "News" to get the money shot isn't ideal!

The website is very poorly designed in terms of accessibility of content-makes me wonder if the owners ever visit it themselves. Nonetheless, I was directed to it after I asked the same questions...if you look under news, their visits to the wind tunnel were in 12/17 and 3/17.

But your explanation does not seem to line up with what you are showing. In both cases the carbon is in tension, with the force coming from the rim bed. This is the equivalent of a dam with water behind it. Looking at the shapes you show, the zipp, hed, etc show a setup that look like Hoover dam (an arch with pressure on the apex of it), whereas your design shows a structure that does not exist in either dams or arches. Is there something that I am missing?


Stephen J

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I believe my local reality has been violated.
____________________________________________
Happiness = Results / (Expectations)^2

I am referring to the spoke point itself. The force of the weight of the rider is transmitted through the spokes, but the spokes are always in tension, as such are pulling on the nipple/nipple bed constantly (albeit at different values as the wheel rotates). As a result, the carbon material at the nipple bed is very important in relation to the rim bed and tire. Because our nipple bed is convex, it is more efficient at handling the tensile force from the spoke.

This is not mine, but found it useful (slightly over simplified):

"In normal bicycle wheels, not those solid fancy ones you see sometimes, I very much doubt there's any compression load on the spokes, actually. If there were any compression, the spoke might just puncture the tire! There's nothing to keep the spokes from going up into the rim and into the inner tube of the tire, other that the tension of the other spokes which keep the rim round.
In general, the load acts on the upper spokes, which are holding up your weight with tension, and on the spokes front and back, which are keeping the rim round. And since the spokes are angled, from the rim and alternating between one side of the wheel hub and the other side, their tension also keeps the rim straight (i.e keeps the rim from wobbling as the wheel turns). That's why you have to adjust the tension of spokes on the two sides of the wheel hub, to take any wobble out of the wheel.
So let's look at some limiting numbers.
First, the worst-case weight each wheel must support (over level terrain, assuming pedals are half-way between wheels) is half of the weight of the bicycle plus rider. And the rider's weight is more than just his mass * gravity. Because the rider might be moving his body vertically, to create extra torque on the downgoing pedal. So some of the time, this downward motion will create more weight, depending on the deceleration as his body comes down on the pedal.
There should be a theoretical minimum tension which must be applied to each spoke. Discounting the effect of that slight angle created by the spokes going to opposite sides of the wheel hub, the spokes in the upper half of the wheel hold up the total weight described above. So,
Total weight / 2 = sum for i = 1 to n/2 of T*cos(theta(i)), -90<theta(i)<90
where theta(i) is the angle from the vertical of the ith spoke, on the upper half of the wheel, and n is the total number of spokes.
The equation simply says that you sum the vertical component of tension for each spoke in the upper semicircle, and that sum must at least be equal to the worst-case weight each wheel must carry. If you solve for T, and all spokes are tightened to that tension, then this would be the point where the bottom spoke will be under zero tension, worst case. You must never allow for compression at that lowest spoke." https://www.researchgate.net/...of_the_Bicycle_wheel

Yeah everyone's wheels are the fastest...statements like: " the fastest overall wheel system for a variety of conditions. " are the biggest bullshit ever.
There is no universal glue, no universal car, bike etc. race for universal do it all items creates mediocre stuff.

Wurf could race aluminum boxed rims and still win with 98% of the IM crowd. What Wurf has to do with 99.99% of people? Marketing BS that's all.

https://www.youtube.com/watch?v=b1TqsoxWhQY

Hm...

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Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)

So, Am I missing something obvious? It seems like either the OP and I are discussing describing different ends of the elephant, or they are trying to market the wrong selling point…but my expertise is in very small tools; not macro-tools such as bicycles.


Stephen J

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I believe my local reality has been violated.
____________________________________________
Happiness = Results / (Expectations)^2

Hi Stephen,

Sorry, I was channeling my inner Robert Chung. ;-)

The quote reveals a basic misunderstanding of how a tension-spoked bicycle wheel carries a load. To me it raises the question: what else is misunderstood?

For example, smoothing the WT data assumes the drag responds smoothly across different yaw angles. But we know that's not how wheels respond across the stall point.

Cheers,
Damon

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Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)

Cheers Damon,


Respect your credentials and assume you not only have mastery of this knowledge, but could also explain it in a cohesive and precise manner: by all means, please, the floor is yours. How would you explain spoke mechanics?


As mentioned earlier - the smoothing of the WT yaw chart was for visual aesthetics. "...we know that's not how wheels respond across the stall point." too.

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Paul Daniels
paul@princetoncarbon.com
http://www.princetoncarbon.com

Hi elevelo,

Jobst's book would be a good place to start. Check out part one especially, 'Theory of the Spoked Wheel', which examines how a wire wheel supports various loads.

https://en.wikipedia.org/wiki/The_Bicycle_Wheel


Cheers,
Damon

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Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)

Erm....whenever I'm compelled by others to doubt my mechanics, at least I can turn to wikipedia (also, conveniently linked to in the article you posted about the book, which I will get around to reading soon).

"Reaction to load[edit]
The reaction to a radial load of a well-tensioned wire spoked wheel, such as by a rider sitting on a bicycle, is that the wheel flattens slightly near the ground contact area. The rest of the wheel remains approximately circular.[13][14][15][16] The tension of all the spokes does not increase significantly. Instead, only the spokes directly under the hub decrease their tension.[12][17][18][19] The issue of how best to describe this situation is debated.[20] Some authors conclude from this that the hub "stands" on those spokes immediately below it that experience a reduction in tension, even though the spokes below the hub exert no upward force on the hub and can be replaced by chains without much changing the physics of the wheel.[15][12] Other authors conclude that the hub "hangs" from those spokes above it that exert an upward force on the hub, and that have higher tension than the spokes below the hub, which pull down on the hub.[18][21]
Despite being composed of thin and relatively flexible spokes, wire wheels are radially stiff and provide very little suspension compliance compared to even high-pressure bicycle tires."

Note, if we tension to, say, 110-120 kgf, we are at roughly 242-268 pounds force. Per spoke. So, on our 16 spoke front we have a combined 4000 pounds pulling radially inward towards the hub from the nipple bed itself. So, I'd say the nipple bed mechanics and material property, layup, and design are important, yeah.

Simple statics. The sum of forces at the hub must add to zero. The weight of the rider+bike is a vertical force (down). The sum of force vectors from the spokes must balance this.

On a shallow rim the lower few spokes contribute nearly all of the upward force. This is because the rim alone has very little vertical stiffness. So the bottom of the rim distorts vertically, and the lower spokes become shorter (losing tension), resulting in a net upward force. The more vertically stiff the rim alone is, the more spokes share in carrying the load. If the rim was infinitely stiff, then I'd guess the top and bottom spokes would share the load equally. Real rims are closer to the shallow rim case than the infinitely stiff case however.

The original point though, that the Princeton rim design reduces point loading at the spoke bed, has nothing to do with this.

The point load will be the same in all wheels with similar spoke count and pattern (and tensioning and rider weight etc etc)

The difference is that the point load at the nipple bed/nipple/spoke interface is distributed across the structural carbon foil more efficiently because of the shape.