[davidgould]

> Can you explain the 'thinner spokes are better' bit?

The rim deflects inward as it contacts the ground. This is controlled by the stiffness of the rim. The deflection untensions the spoke. The cycle of tension/untension as the wheel rotates causes fatigue and also if the tension reduces to near zero allows the nipples to unwind. A thinner spoke elongates more for a given tension, so the rim deflection reduces tension proportionally less.

For example, given a thin spoke that elongates 5mm under tension, and a thick spoke that elongates 2mm, a 2mm rim deflection reduces tension 40% on the thin spoke and 100% on the thick spoke. So the thick spoke will fatigue and fail faster.

Ideally use the thinnest spokes that can deliver the desired wheel tension. This is not commonly done in cheap wheels because thin spokes have more windup and more spokes interact when truing so the build takes more time and care.

[wiredfool]

Yep, that's it.

The key is that spokes never fail from tensile overload (barring something like a branch going through the wheel), they fail from fatigue cracks. A spoke will be unbuildable before it has too little tensile strength.

[jacquesm]

Thanks! (Both of you).