N gauge wheelsets

I would like to change the wheelsets on my N-gauge Freight Car Rolling Stock (mostly Atlas) from plastic to metal. I use Code 80 track. Which scale size do I need 33" or 36"? Is one brand of metal wheelsets better than another?

Welcome.

You might do better by asking in the Model Railroader General discussion forum but here is a link from a search.

http://www.hobbylinc.com/atlas-33-metal-wheels:axles-12-n-scale-model-train-trucks-22020?source=froogle&gclid=CIiS-Mi2_NECFUI8gQodp2sAtA

Not many watch this forum.

Rich