2 vs 3 spoke crossing

igstar
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2 vs 3 spoke crossing

Postby igstar » Fri Oct 14, 2011 11:28 am

I'm looking to build a couple of wheels - 32 spokes each. It appears that the common cross thread for spokes is 3x, however I have seen some people doing 2x. Can someone explain benefits of one over the other?

rustychisel
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Re: 2 vs 3 spoke crossing

Postby rustychisel » Fri Oct 14, 2011 11:38 am

Minimal. It's not even an easier build.

You might save 20~ 30g per wheel in reduced spoke weight, ie reduced spoke length which is I think about 4mm per spoke.

The benefit is said to be in slightly enhanced stiffness due to the fact that the spoke exits the hub at a less tangential angle, taking a slightly more direct path to the rim. The build quality of the wheel is more important, I suspect.

human909
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Re: 2 vs 3 spoke crossing

Postby human909 » Fri Oct 14, 2011 11:56 am

From a engineering structural view. (at least my quick analysis)

For a given number of spokes and the same spoke tension. The less cross overs there are the greater the radial tension is and thus the stiffer the wheel is RADIALLY. The more cross overs there are the greater the torque transfer (important for in the rear wheel for heavy powerful riders and for disc brakes)

The most important wheel attribute of lateral stiffness is less effected. While the lateral tension is identical between lacings, the larger spoke length means that flex is increased proportionally.

Mark Kelly
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Re: 2 vs 3 spoke crossing

Postby Mark Kelly » Sat Oct 15, 2011 10:49 am

rustychisel wrote:Minimal. It's not even an easier build.

You might save 20~ 30g per wheel in reduced spoke weight, ie reduced spoke length which is I think about 4mm per spoke.



The weight saving is about 4 g on a standard wheel, not 20, based on a length difference around 6mm between 2X and 3X. The length comes off the middle part of the spoke which is the thinnest and thus lightest; 1.8mm dia SS wire has a mass of about 20g / metre, 6mm x 32 spokes is about 200mm.

AdamM
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Re: 2 vs 3 spoke crossing

Postby AdamM » Tue Oct 18, 2011 6:09 pm

In real world terms I doubt you'd notice any difference in performance for the same spoke count. But they will look different so that might appeal to you. For conventional wheels you may as well stick to 3x (and you will have to for the rear drive side and where using disc brakes, as stated above).

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