• Would that not have a negative effect on breaking performance?

    It probably has a positive effect of breaking performance, since none of the original extrusion is machined away. Braking performance is barely affected, but you do have to scrub flakes of alumina out of your pads and the rims quickly start to look like machined ones as the soft anodising wears off.

  • Before committing to the NMSW life, have a look at some Mavic CD (couche dure = hard coat) rims from the 80s and 90s and then remember that hard anodising lasts about 10 times as long as the soft anodising you'll find on current rims.

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