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PostPosted: Wed Apr 16, 2014 4:02 am 
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The SS is 13% lighter than the cx-ray. It stands to reason that you could build a wheel of the same strength and mass using 13% more super spokes - 18 SS vs 16 cxrays for instance.

Why am I wrong?

Edit - the cx-super is 17% lighter.

I am miffed that Sapim would make this elementary mistake. The stiffness of a spoke is determined by the material modulus of elasticity, not the tension on it.

"The recommended spoke-tension to build a stiff wheel-set with the Super Spoke is:

Front wheel: at least 950N
Rear wheel: at least 750N (opposite of the sprocket wheel)

As you probably already know, a high tension is always better. The higher the tension the stiffer the wheel."

http://www.sapim.be/spokes/butted/super-spokes


Last edited by F45 on Thu Apr 17, 2014 9:06 pm, edited 1 time in total.

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Posted: Wed Apr 16, 2014 4:02 am 


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PostPosted: Wed Apr 16, 2014 5:26 am 
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My understanding is that <spoke's cross section(or unit weight) x spoke number> is not proportional to lateral stiffness.

There are more factors that affect a wheel's stiffness, such as rim stiffness and hub dimensions.

Thus, reducing the spoke number by half and using spokes twice as heavy doesn't make a wheel with the same stiffness.


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PostPosted: Wed Apr 16, 2014 11:00 pm 
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F45 wrote:
The SS is 13% lighter than the cx-ray. It stands to reason that you could build a wheel of the same strength and mass using 13% more super spokes - 18 SS vs 16 cxrays for instance.

Why am I wrong?

Even if that were true you'd only be saving about 10 g at most and it would cost you $100 extra, I don't see the advantage.


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PostPosted: Thu Apr 17, 2014 11:55 am 
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If you're considering the Super spoke, I recommend going for the CX-Super (when attainable). This is the bladed version of the Sapim Super spoke with the same advantages over the Super Spoke as the CX-Ray over its round counterpart, the Laser.

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PostPosted: Thu Apr 17, 2014 1:47 pm 
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Hi,

Quote:
I recommend going for the CX-Super (when attainable).


The j-bend version seems to be available. (At long last)

Ciao, ;)

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PostPosted: Thu Apr 17, 2014 8:59 pm 
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pam wrote:
Even if that were true you'd only be saving about 10 g at most and it would cost you $100 extra, I don't see the advantage.


What I'm saying is, say you wanted to build up a 16 spoke front wheel. You could build it with 18 SS and spread the load out more evenly for the same overall weight.

Point taken on the CX-Super.


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PostPosted: Thu Apr 17, 2014 9:27 pm 
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Hi,

You want to build a 16 spoke wheel using 18 spokes? :lol:

If you want to build a x gram wheel and use 18 Super spokes then it would be stiffer than the same build using 16 cx-rays. That's what you mean, correct?

Ciao, ;)

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PostPosted: Thu Apr 17, 2014 11:10 pm 
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Not stiffer, stronger, because the load is distributed on the rim more uniformly.


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PostPosted: Thu Apr 17, 2014 11:29 pm 
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Hi,

O.K. but you will have killed two birds with one stone though: it will end up stiffer and stronger.

Ciao, ;)

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PostPosted: Fri Apr 18, 2014 3:01 am 
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F45 wrote:
I am miffed that Sapim would make this elementary mistake. The stiffness of a spoke is determined by the material modulus of elasticity, not the tension on it.


Actually modulus x cross section / length.

Pretty sad, but hey... they just make spokes, they don't need to know anything about wheels.

They have some practicality for front wheels if your hub has a high bracing angle, and also for the NDS rear if your NDS offset is high relative to the DS. The 1.8mm threads are annoying however.

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PostPosted: Fri Apr 18, 2014 3:58 am 
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Hi,

Quote:
I am miffed that Sapim would make this elementary mistake.


As far as I can tell from the link you provide that's not what they're claiming:

Quote:
As you probably already know, a high tension is always better. The higher the tension the stiffer the wheel. Please make sure that you respect also the requirements provided by your rim-manufacturer and do not forget that the tension of each wheel-side should be equal.


When I read this I have the idea they actually mean stiffer in the horizontal plane referring to the wheel.

That said, a translation is rarely perfect. and of course the build the spokes, not the wheels...

Ciao, ;)

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Posted: Fri Apr 18, 2014 3:58 am 


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