I feel that using the brass wheels and brushes is alot less aggressive on chrome when it comes to removing minor rust. The brass does not scratch the finished surface up near as much as steel. I do however use steel when I am stripping down to bare metal with intentions of painting afterwards.
When I bought my grinder, I tossed the steel brush that came with it and bought a brass one. No contest. It still removes rust and paint but is nowhere near as aggressive as steel.
Grab some of these little throw away brushes too. They are great for getting around spoke nipples and such. I use these on wheels along with my wifes glass top stove cleaner and the chrome shines right up.
I bought a new 4 1/2" angle grinder a few years ago, a Ryobi. And it came with a brass wheel. That thing was awesome, removed all the scratched up clearcoat on a chrome Flightliner frame. Haven't seen another one since. -Adam