Originally Posted by
grumpus
Really? You can pretty much do that by sticking abrasive paper to your brake blocks and coasting down a hill.
When they said machined sidewalls, I think (not certain) they meant ones with intentional machining grooves running cross or diagonal to pad direction, sorta like from a slightly inclined fly-cutter or insert machining head. I think I've seen rims like that, and also with some sort of ceramic coating (cerakote, like firearms?) I could really use that, my rims are too polished smooth, but also concaved and thus thinning there, I don't want to remove any more metal, even with a small flexible sanding disc.