Tensioning Sapim CX-Ray spoke w/DT Swiss tension gauge

[carbon man]

I’m planning to build a wheel set using Sapim CX-ray spokes. I currently own a DT Swiss Tensioning gauge but I have never used it aero spokes before. Does anyone know what tension range I should be shooting for using this gauge on the Sapim CX-Ray's?

 

[fish156]

I’m planning to build a wheel set using Sapim CX-ray spokes. I currently own a DT Swiss Tensioning gauge but I have never used it aero spokes before. Does anyone know what tension range I should be shooting for using this gauge on the Sapim CX-Ray's?

I don't know if you already have found this, but here's the tech page for those spokes:

http://www.sapim.be/index.php?st=products&sub=spokes&category=3959&id=3340&detail=aero

It does not specifically mention the tensioning spec for those spokes. It's possible that they do that on purpose, just as Mavic does not give out tensioning specs for their rims to the public ("dealers only"). Tensioning specs may be somewhere else on the Sapim site, but I did not see it.

This next URL page contains a list of Sapim agents. The guys in the US are KHS and they also rep for Cane Creek. I have talked to them before and they were very helpful. I suggest you call your local agent and ask them.

http://www.sapim.be/index.php?st=agents

If you get an answer on your question it would be nice to hear back. Good luck!

 

[fish156]

I’m planning to build a wheel set using Sapim CX-ray spokes. I currently own a DT Swiss Tensioning gauge but I have never used it aero spokes before. Does anyone know what tension range I should be shooting for using this gauge on the Sapim CX-Ray's?

Poking around on the Sapim site I also found a cool tool for preventing aero spokes from winding up when you are tensioning them. See item #7:

http://www.sapim.be/index.php?st=products&sub=racetools

You accomplish the same thing by taking a pair of pliers and wrapping the jaws with electrical tape, but this Sapim tool actually looks nice to use as it appears you just stick your finger through it and grab the spoke. The "pliers with taped jaws" works, but it's kind of unwieldy. This Sapim tool looks to be much faster and elegant.


One other source of tensioning info (if all else fails) is the Tension Meter Conversion Table for the Park TM-1. Just disregard the TM-1 specific scale on the left side of the page and use the Kgf numbers. You'll have to do some coversion from Kgf to the scale that your DT gauge uses. They give numbers for seven different types of bladed spokes and maybe you can match up yours to whatever is the closest match. See:

http://www.parktool.com/products/documents/TM_1table_2005912_4301.pdf

 

[artmichalek]

...but this Sapim tool actually looks nice to use as it appears you just stick your finger through it and grab the spoke. The "pliers with taped jaws" works, but it's kind of unwieldy. This Sapim tool looks to be much faster and elegant.

That's a pretty good idea. If it fits on your finger, it would mean one fewer thing to juggle while going around the wheel.

The reason why most manufacturers don't give specs for spoke tension is because the appropriate tension depends on the rim, hub, lacing pattern, rider weight, and expected use. To publish a spec would mean either a uselessly large range, or a lot of lawsuits.

 

[Belgium Bike]

Hey,
We build wheels with Sapim CX-Ray spokes.

Sapim Belgium recomands for a 38-50 mm carbon rim 100 kgf for front and 140 kgf for the back drive side.
I don't know how much that messures on the DT-swiss meter.

Thanks
BelgiumBike

 

[tafi]

The cross-section of a Sapim CX ray is very similar to that of a DT Aerolite and they are made of very similar material. It would stand to reason that you would measure tension the same way with either of these, so, if there are any instructions relating to the Aerolites, then start with those.