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 Post subject: Re: New Shamal Mille!
PostPosted: Sun Jul 20, 2014 1:03 pm 
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Joined: Tue Dec 27, 2011 2:19 pm
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Flex...


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 Post subject: Re: New Shamal Mille!
Posted: Sun Jul 20, 2014 1:03 pm 


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 Post subject: Re: New Shamal Mille!
PostPosted: Mon Jul 21, 2014 9:01 am 
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Joined: Mon Aug 04, 2008 11:09 am
Posts: 332
What do you think happens with the flex? It will be transfered back. I'm sure there will be some losses, but 17% (as claimed by Campa): utter disbelieve here.

Quote:
As in the 2-Way Fit™ version, the Shamal™ Ultra™ 2012 wheels for tubular or clincher, roll to the starting line with the best performance ever. MegaG3™ and the oversized flange make this wheel extremely quick off the line and reactive, featuring a full 17% increase in reactivity over the previous version!


So not only is G3 superior, Mega G3 adds another 17% in reactivity.

I wonder what Ultra G3 will bring to the table :D

Also the claim that spoking patern makes a noticeable difference for lateral resistance is simply not supported by research. Spoke paterns aren't that important for lateral resistance. They do have quite an impact on torsional resistance, but how muc h between G3 and 2:1 is anyones guess. G3 certainly isn't a bad design for a rear wheel, far from it, but the stated advantages are not as big as claimed by Campa or it's representative. It's advantage (even spoke tension) brings a disadvantage in large parts of the rim which are unsupported and thus need to be structural sound. As that is certainly the case for Campagnolo wheels it's not an issue, but conceivably there's a slight weight penalty involved (rim is a tad more beefy ). Then again, it would be a slight difference pretty much filtered out by all the other random shizzle going on.


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 Post subject: Re: New Shamal Mille!
PostPosted: Mon Jul 21, 2014 1:31 pm 
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Location: Expat in Washington DC
The real advantge to Campag is that the G3 configuration can be spotted from a 100 feet.


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 Post subject: Re: New Shamal Mille!
PostPosted: Mon Jul 21, 2014 6:27 pm 
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Joined: Sun Dec 27, 2009 10:55 pm
Posts: 106
Location: Honolulu
corky wrote:
The real advantge to Campag is that the G3 configuration can be spotted from a 100 feet.




Some of us looking for a stiff light climbing wheel might live with, but regret that feature.


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 Post subject: Re: New Shamal Mille!
PostPosted: Mon Jul 21, 2014 11:40 pm 
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Posts: 76
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Franklin wrote:
What do you think happens with the flex? It will be transfered back. I'm sure there will be some losses, but 17% (as claimed by Campa): utter disbelieve here.

Quote:
As in the 2-Way Fit™ version, the Shamal™ Ultra™ 2012 wheels for tubular or clincher, roll to the starting line with the best performance ever. MegaG3™ and the oversized flange make this wheel extremely quick off the line and reactive, featuring a full 17% increase in reactivity over the previous version!


So not only is G3 superior, Mega G3 adds another 17% in reactivity.

I wonder what Ultra G3 will bring to the table :D

Also the claim that spoking patern makes a noticeable difference for lateral resistance is simply not supported by research. Spoke paterns aren't that important for lateral resistance. They do have quite an impact on torsional resistance, but how muc h between G3 and 2:1 is anyones guess. G3 certainly isn't a bad design for a rear wheel, far from it, but the stated advantages are not as big as claimed by Campa or it's representative. It's advantage (even spoke tension) brings a disadvantage in large parts of the rim which are unsupported and thus need to be structural sound. As that is certainly the case for Campagnolo wheels it's not an issue, but conceivably there's a slight weight penalty involved (rim is a tad more beefy ). Then again, it would be a slight difference pretty much filtered out by all the other random shizzle going on.


Ummm, having done some research on this, I beg to differ.

The lateral rigidity increase that we see is that under torsional load, applied offset to the centre-line of the rim, produces less distortion of the rim in the lateral plane than is the case with a conventionally spoked wheel.

If you care to do it (and have the kit, time and inclination) you can replicate the method that I used to inspect the claim - you see, I may run Campagnolo's UK main UK SC - but I was a wheelbuilder a very long time before that ...

The method is:

Take 3 rim identical blanks (I used blanks from KinLin which are fairly freely available and not hideously expensive), drill one evenly spaced 28H, drill one 2:1 spaced, 21 hole and drill 1 G3 spaced, 21 hole.

Apply a compressive load to the G3 - format rim so that the interspoke areas are depressed. It took me a little trial and error to get the degree of depression correct as my FEA technique isn't up calculating it. It's tricky to do but I managed it on a surface table with a steel ring (actually a hub bearing outer ring from a Saladin armoured car), seven sash cramps and seven shaped pieces of wood.

Build all three rims 3x and radial using the same hub (can't prove Mega G3 *exactly*but you can get a very close analogue of it if you use a Miche LF track hub, turn the NDS flange down and re-drill it) using consistent spokes (in my case Sapim 2.0 mm PG) and nipples (Sapim Polyax) and make the total tension distributed within the wheel the same in all 3 cases.

You can then ...
    Take a tension graph of the unloaded wheel for reference and to check that you have consistent (or very close to consistent) spoke tension all the way around.
    Fit a tyre and tube and do the same - note where the inconsistencies in the rim response lie and check that the wheel has remained true. Correct any trueness errors, remeasure.
    Placing each of the three wheels in a consistent orientation (i.e. with reference to one of the NDS spokes vertical and running from the centre to the six o'clock position) Place a static load on the hub bearing downwards and measure the tension in each spoke - graph again.
    The distortion in the rim will be reflected in shifts in the spoke tensions. The way those shifts takes place is instructive & different between all 3 types. Higher tension indicates an "outward" displacement of the rim. Reduction in tension reflects a corresponding inward displacement of the rim. You *could* double check this with a dial gauge measuring the hub / rim displacement change but the actual differences are very small and changes in tension are an adequate analogue and easier to measure.
    Screw a sprocket onto the hub, anchor the rim and apply a consistent torque to the sprocket. Remeasure the spoke tensions. Displacement in the lateral plane will be reflected in a shift in the spoke tensions between drive side and non drive side.

I have done all that - it took about a week and a lot of false starts - and the data which it generated, we use in our G3 building course - and I can assure you that the results, rough though they are, do indicate that Campagnolo (surprisingly enough) do know something about the product that they have invested many 10s if not 100s of 1000s of Lire / Euros to design and make.

It's also worth noting, "reactivity" as used in the marketing spiel is *not* the same as torsional resistance - Campagnolo use the term *reactivity* which is their proprietory matrix of rotational inertia as well as resistance to both torsional and lateral rigidity. It is not a definable engineering term as such. They do, however, test head-to-head with other brands to determine differences.

Sorry to bang on - skepicism is sometimes - often, even - good - but if you want to believe or disbelieve something, one way to anchor your faith is to test your skeptical hypothesis with an open mind. When I did the above, it was after I received some tech data from the factory that I wasn't too sure about, so I set out to test it as best as I could (and, TBH, to see if I could figure out how ... the technical challenge interested me).

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 Post subject: Re: New Shamal Mille!
PostPosted: Tue Jul 22, 2014 12:24 am 
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Joined: Mon Apr 03, 2006 8:53 am
Posts: 339
I would also point out that, the math on the G3 lacing has been done by other independent 3rd party wheel/hub builders. In fact I am 95% sure it was in this message board. : )


C


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 Post subject: Re: New Shamal Mille!
PostPosted: Tue Jul 22, 2014 3:54 am 
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Joined: Sun Nov 07, 2010 9:14 pm
Posts: 1294
I have been using Campagnolo wheels, and others, for a long time. I'm a bigger guy and the G3 pattern looked a little suspect to me at first. My first G3 wheels were the Eurus (stainless steel spokes). Bullet proof. Stable and true, no matter how much torque I could apply. And the design is just spot on... I always look to see how tangential the spoking is and these are very good. I can't say I'd trust any other 21 spoke rear wheel with relatively normal spokes. I've also ridden Lightweights. They are stiff wheels, but I prefer the Boras.

Then, when you get to the hubs... well... they're just perfect in my mind. I'll take loose bearings and finely machined cups and races any day over cartridge bearings. Very simple to service, although they rarely need it.

I am looking forward to seeing the new Boras. I run tubulars so wasn't too concerned about a wider nominal width of the rim, but a larger radius rim bed to better accommodate wider tires might be nice. I run Veloflex Arenbergs (25mm) now and have no problem with the current Boras, but I guess everyone has to follow the trends at some point.

I can't really tell from the pics, but it appears that while they might be a bit wider the inside edge at the spoke nipples doesn't appear to be as U-shaped as a lot of other current wheels. The claims from other manufacturers are that this is where the "added stability" in cross winds comes from. We'll see. The bora rims are really strong in their current form, and I have found that simply going to 25mm tires over the 23's has greatly increased both comfort and stability.

It is a little strange that the new Fulcrums don't seem to have adopted the wider rim, especially in the clincher version where I can see some actual benefits. And I agree with the previous poster about it being kind of a pain to have to adjust your brakes all the time just for switching out wheels. Consistency is good. Even though you can now use the same brake pads for both carbon and alloy, I don't think that precludes a careful inspection of the bads after a swap from alloy to carbon to ensure that the pads are free of any alloy particles that may have gotten embedded in the pads while they were being used with the alloy rims.

Looking forward to seeing these things for realz.

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 Post subject: Re: New Shamal Mille!
PostPosted: Tue Jul 22, 2014 7:06 am 
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Joined: Thu Apr 08, 2004 3:31 pm
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Location: Hollywood
@graeme_f_k

You speak as though you invented G3 spoking! Such a great post. I love it when baseless skepticism gets stoned by factual data as you presented. Post of the year. Chapeau.

G3 *is* awesome.

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 Post subject: New Shamal Mille!
PostPosted: Tue Jul 22, 2014 8:59 am 
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@graeme... I forgot to ask earlier... One of my takeaways from your excellent post was that the G3 rims, untensioned, are not perfectly round by design and that once tensioned the entire structure is round and even and every component (rim, spoke, hub) acts to produce a superior wheel structure compared to a normally laced wheel. Would you say that's a fair paraphrasing? And does that apply to the Boras as well as the Shamals?
Thanks.
And +1 to ElDuderino's post above.


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 Post subject: Re: New Shamal Mille!
PostPosted: Tue Jul 22, 2014 9:16 am 
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Joined: Mon Aug 04, 2008 11:09 am
Posts: 332
ElDuderino wrote:
@graeme_f_k

You speak as though you invented G3 spoking! Such a great post. I love it when baseless skepticism gets stoned by factual data as you presented. Post of the year. Chapeau.

G3 *is* awesome.

Except he did not use factual data at all :noidea:

On the other hand I did quite some research yesterday and the factual data most certainly does not stone the scepticism. As I said for rear wheel it's a decent idea, with it's own compromises. It would be nice if Graeme would support his claims by factual data....

1. spoking patern has a limited impact on lateral stiffness

http://www.astounding.org.uk/ian/wheel/patterns.html

Note he actually has a similar amount of spokes on the radial wheel, whereas G3 actually decreases the spoke count versus traditionally spoked wheels:

Quote:
So, a radially spoked wheel is about 4.6% stiffer than a tangentially spoked one. Alternatively, if you apply 1000N (about 100kg, 220lb) to each of the wheels, the tangential (four-cross) spoked one deflects 0.0075mm (0.0003 inch) more than the radial spoked. Since the tyre is likely to deflect several millimetres at least (if 3mm, that's 400 times more deflection) I conclude the spoking is unlikely to make a discernible difference to the vertical stiffness of the wheel.


Now why would Campa score high with G3? The spokes are thicker. It's not sas much the spoking patern as the materials used.

Another test shows Campa to do pretty good... but though they take top spot other Campa wheels with the same patern end up in the middle:

http://www.rouesartisanales.com/wp-cont ... e_rear.gif

Surprising is how Bora with high rims (generally stiffer) scores worse than the Eurus wheels with low rims (certainly Bora score fine, just an observation on the data). Otoh Mavic Cosmic score higher than their lower counterpart (which is what you would expect).

Of course MEGA G3 might change all that, but count me sceptical due to the distinct lack of data. Sorry Graeme, I take manufacturers claim without any supporting data with a huge grain of salt.

2. Deflection of the rim> Now imagine that this is G3 with large parts with no spokes:

http://www.astounding.org.uk/ian/wheel/index.html

How to counteract? More strength at the rim (which isn't a bad thing as the wheels are indeed bulletproof. Notice that one of the flaws of G3 (more deforming at the rim due to large gaps) also forces Campagnolo to use very srtrong rims... and that's a good thing overall. But it's not exactly the lightest,

We can repeat: Now why would Campa score high with G3? It's not sas much the spoking patern as the materials used.

Then to use Thor's hammer to smash any notion of factual data:

Quote:
It's also worth noting, "reactivity" as used in the marketing spiel is *not* the same as torsional resistance - Campagnolo use the term *reactivity* which is their proprietory matrix of rotational inertia as well as resistance to both torsional and lateral rigidity. It is not a definable engineering term as such. They do, however, test head-to-head with other brands to determine differences.


In other words:
1. Unknown methodology
2. Unverifiable
3. Undefinable

He full on admits the claims are nonsense :mrgreen:

Do I trash Campa wheels? Nope, read my posts I certainly do not, they are very good. Do I say G3 is bad? Read my posts, I certainly do not say it's a bad way to spoke a rear wheel. But G3 has compromises and the claimed advantages are unverifiable. Those that can be verified (lateral resistance) are at best extremely minimal with the compromises in the background (rim deformation)! So though it's a good way to make a rear wheel, it's not "superior".


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 Post subject: Re: New Shamal Mille!
PostPosted: Tue Jul 22, 2014 12:19 pm 
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Location: Aix en Provence
All of this theoretical discussion while interesting does not replace a real life test. I have Bora 50, Bora 35, 2 shamals all with the G3 lacing. it just plain works and is very reliable and stiff.


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 Post subject: Re: New Shamal Mille!
PostPosted: Tue Jul 22, 2014 3:12 pm 
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@Franklin, he's done a lot more than you have, clearly. I admire seeing someone actually research the "how and why" aspect of manufacturer claims instead of seeing a photo of a product and saying "that will never work."

Cmmon, man.

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 Post subject: Re: New Shamal Mille!
PostPosted: Tue Jul 22, 2014 6:12 pm 
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Posts: 332
ElDuderino wrote:
@Franklin, he's done a lot more than you have, clearly. I admire seeing someone actually research the "how and why" aspect of manufacturer claims instead of seeing a photo of a product and saying "that will never work."

Cmmon, man.

Point out the data which you find so fantastic. He gave ZERO data, only keeps on claiming unverifiable things. OTOH, who did post data... oh that's me.
I asume that you applaud my post as best post ever as I actually use data and ask Graeme toactually come with some proof instead of just empty claims? :beerchug:

LionelB; I never said differently. But do you actually belief your wheel has more reactivity (17%), so you are faster from the start line? ;) Do you feel more torsional stiffness over traditional wheels which result in more power? Or is it just something that works as good as any other good wheel? ;)


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 Post subject: Re: New Shamal Mille!
PostPosted: Tue Jul 22, 2014 7:04 pm 
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Sheesh... I hope for everyone's sake that @graeme_f_k doesn't just throw up his arms and quit contributing. As far as I'm concerned he is probably the most knowledgeable Campy guy on this forum, with access to information that the rest of us just don't have. His posts are well reasoned and explained, and highly credible in my opinion. With Google and the internet it is easy to search for whatever you want in order to find something that you feel supports your own opinion (valid or not) and dismiss information that doesn't. Even though @Graeme_f_k may work for Campy, I don't feel he takes anything for granted. Hence we have him going out of his way to explain in considerable detail the steps he took to verify the claims that his own employer is making. @Graeme_f_k has gained credibility in my mind not from simply doing a few searches but by actually doing the work to verify as best he reasonably can the validity of his comments. I do think he looks at both sides of the equation, always. That's rare, so good for him. I wouldn't even waste my time trying to explain the errors in the comments trying to undermine @grame's earlier post.

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 Post subject: Re: New Shamal Mille!
Posted: Tue Jul 22, 2014 7:04 pm 


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 Post subject: Re: New Shamal Mille!
PostPosted: Tue Jul 22, 2014 7:50 pm 
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Joined: Thu Sep 12, 2013 8:17 am
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corky wrote:
The real advantge to Campag is that the G3 configuration can be spotted from a 100 feet.


Yup. Like Apples rubbish headphones: Everyone in the carriage knows you have an ipod from the tinny rendition coming out your ears


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