This. It's the overlap of the plain weave strip used to form the sidewall. This is apparent on all rims, but most use unidirectional on the sidewall and it's harder to pick up the discrepancy as the overlap is typically cut at the same angle of the fibers.

---

________________________________________________________
Ben Waite | Zipp Senior Design Engineer | The Power of Bicycles: Please contribute to World Bicycle Relief | Zipp | SRAM | Quarq |