Note that "black" wheels are actually dark grayish-black due to clear "tire" material over the black plastic inner rim. Skater weight of 175 lbs on antique Chicago Black Panther plates (with limited clearance, really needs 57mm or less wheels). The grip on these wheels is unbelievable on a coated wood floor, no slippage at all (was afraid to try a floor slide stop). They also appear immune (time will tell) to picking up the black residue that appears to inhabit this particular floor, and "coats" many wheels. But as always, the trade-off for these sticky wheels is having to push harder and more often (i.e. less "roll") than on harder and less sticky wheels. These are not what I would consider a "speed" wheel - but also not as soft and slow as an outdoor wheel. So a compromise wheel that falls in-between, perhaps slightly closer to the speed wheel zone. Rollerbones Turbos 62mm (97A) have much better roll, but less consistent grip, at least partially due to black residue accumulation. These wheels definitely have their place - perhaps places and applications that need more grip and quick directional changes (roller derby, hockey) without a high priority on speed or for lighter skaters in search of grippier wheels.