Hi there-
The Athearn BB SD9 I’m working on now is missing two wheelsets and I’m replacing the other four. What is the stock wheel size for the SD9?
As far as I know all Athearn blue box locos used 42" wheels.If your locois one of the newer ones with plastic side frames you canj buy the complete wheelsets from Athearn.If this is so be warned the nickel silver wheels are a bit slippery so what I do on 6 axle units is replace the outer wheel sets with the nickel silver wheels but keep the sintered iron sets for the middle as these will help with pulling power while the nickel silver sets willhelp with power pick up.