Originally Posted by
FBinNY
yes, if by deliberate, you mean that the makers left the scroll marks rather than make the effort to eliminate them.
The scroll marks are the result of the radial tool path while the rim is turning. The pitch is equal to the feed (radial distance per revolution) so coarse scroll marks are the result of fast feed rates whose benefit is a shorter cycle time and lower cost. There are various ways to eliminate scroll marks, but they all have drawbacks and raise production cost. OTOH- if you do a great job eliminating any hint of scroll marks, how would buyers know the rim has machined sidewalls.
So it's smarter to leave them in and let marketing sell the look, than to spend the dough to eliminate them.
I've worn through the anodizing on a new wheel. The brake pads leave streaks before they establish a wear track all the way around a rim.
Ridges may also increase the braking power slightly by adding surface area.
Only the very lowest end parts have tool marks which are that coarse. They leave the ridges to hide the streaks and possibly increase braking power a bit.