Head Driven Nipples
It took me some times to arrive to Head driven Nipple. But now... I almost build only with them.
My preference is like this :
Aluminium for lightweight builds :
- Sapim double square. Very good nipple with strong Aluminium 7075 T6 ! You can work with them without scratching the color or rounding them. Good for repair with the tire on after years.
- DT Swiss Squorx Aluminium for DT Swiss PHP whashers rim. DT Swiss says it mandatory with their PHP rims. I prefer Sapim Nipple and might change. I will measure them, compare, test and I will tell you my final words.
- Sapim Hexagonal for very flat rims. Where other head driven nipple will protube.
Brass for heavy weight, no research of weight gain.
- DT Swiss Squorx (mainly because I got them at better price than Sapim...). They are Pro Head, which means with an inside round head, like Sapim Polyax : the angle of the spokes entering the rim can go up to 9 - 12°.
I did not test other brands of head driven nipples. Sapim nipples have such a good reputation I am satisfied, than I did not felt the need to try others.
Why are they so pratical ?
1) The head disengages more precisely than slotted nipple. You can then drill them more accurately and with more tension. It saves times and the wheel is sometimes almost ready.
Here is how I proceed : I drill - at max speed - at 3 mm, then I do another round at 4 mm (DT Swiss trick to obtain equal tensions by making the few last turns with less difference in spoke tension). Normally, the spokes are directly in the perfect range to adjust and work with them.
BSC makes the drilling tool.
2) Once your spokes lenght calculated from the ERD, you need to add 1 mm to accomodate Sapim Double square or DT Squorx nipples. Consequences : The wheel will be more easy to lace with longer spokes. And more importantly, it will prevent head brokage because the spoke will most certainly fill the head, even with too short spokes.
3) With thin spokes at 1.65 mm and a lot of windup, you can grab the spoke near the nipple and adjust from the head.
In all, there are a bit more expensive than other nipples, but the advantages are awesome.