Weight Weenies

Could you then please explain me the difference on the strenght Sapim gives for CX-Ray (1600 N/mm2) and Laser (1500 N/mm2)?

Giant DK wrote:Could you then please explain me the difference on the strenght Sapim gives for CX-Ray (1600 N/mm2) and Laser (1500 N/mm2)?

You would have to ask Sapim.

-Eric

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The cold working process used to flatten the spokes strengthens the steel.

http://en.wikipedia.org/wiki/Work_hardening

Cold working usually increases brittleness as well.

ergott wrote:You would have to ask Sapim.

-Eric

Well, the diffence in the strenght implies that they are not made of the same steel. CX-Ray are made by a stronger material. Not much but according the given strenght there are a difference. You don't have to ask Sapim about this - unless you don't trust what Sapim writes on their webpage.

natiedean24 wrote:Cold working usually increases brittleness as well.

That's true. I have seen exsampels on steel that have been "cold worked" (bend) that much that it actually becomes brital like glass. You kick it and it sort of "explode"... But this doesn't change the yield strenght of the material.

As I said in a previous post, I have been performing the test this afternoon.
Rim is an XR300, 20 spokes tensioned at 900N, and a DT240s front hub. Very same hub, very same rim. Lateral load applied at the very same place/same side of the rim.

The results are attached to this post. These are the raw results, that's why you can see the lines are not very straight. The measures would need some minor adjustments.

As you can see, the difference in lateral stiffness between the DT Competition and the DT Aero Comp is marginal. I imagined it would have been more important. Thanks for the comments that led to this interesting test.
The lateral deflection is not enough to make the spoke bend significantly and measure an important difference. Spokes mostly deal with elongation during the lateral loads.
It would be interesting to see what happens when the deflections are more important (flexy rim, low spoke count).

Nevertheless, there is a constant small difference in favor of the DT Competition. I need to figure out if this is a true stiffness difference or if this is a difference in the "0" position of the "0°" gage. Since the "180°" deflection is different too, I tend to think there really is a rigidity difference between these two spokes.

I'll perform further tests to make it clear.

Finally, you can also see that the 180° deflection is lower for the flexier wheel.

Cheers,
Adrien.

Thanks again Adrien. Do you have any plans for more wind tunnel testing? Lots of great new designs that need to go head to head. I'll loan you my 6.7s if you need.

Eric

Andien, I'm interested to know if these new ENVE wheels are "SOFT". I absolutely hate soft wheels.......some good example of unridable wheels of Reynolds KOM and the 2008 16/20 DV46 UL.

If you happen to run any test in the future, please share the result.

Thank You

What hubs do you guys recommend. I am a 200lb. rider right now but trying to drop 15-20 over the next 3-4 months. I am love Dura Ace hubs but apparently can't get them in the correct spoke count for these wheels. Thanks for the help.

new Enve 8.9 wheels

Too much.

Wow... Those are not bold enough, you should make your decals reflective!

http://www.instructables.com/id/Paint-y ... eflective/

That bike looks utterly wicked!

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Holy Black and White flashback Batman! I think you need a bit more drop