To paint wheels,brackets, and other odd shaped pieces, I'd spray the paint. The easiest and cheapest route is to use rattle cans from the hardware store. A better plan is to use the little Preval sprayers. These sprayers are similar to the rattle cans, but allow a person to spray better quality paint. In fact, regular automotive paint can be used with these. (but wear all the necessary safety gear) These little sprayers are available at Hardware stores, paint stores etc. To see what they look like:

www.preval.com

It is critical to get the paint mixed thin enough so it will spray properly. If it's to thick the results will NOT be good!! (or it may not spray at all!) I'd suggest spraying some on a practice piece first.