Kadee are mainly metal wheels with plastic axles, which I dislike, there are quite a few manufacturers of metal wheels, Walthers, Kadee and Intermountain to name a few. I get mine from China all metal wheels and axles.
As already mentioned they are different sizes and types, ridge back, smooth etc. so check the type and size you need as
@boatwrench has already posted.
Metal wheelsets are easy to clean when needed, keep track track clean for longer, I will mention that one side is insulated so fitting them with power pickups as I do, is simple and easy to do.
Axles won't deform and there is less friction in the journal as metal axles have pin-point ends whereas plastic axles tend to have blunt ends.
Just be aware when fitting all metal axes you need to space the trucks to fit the axle, difficult if it's a Bettendorf metal truck as they are easily broken.
Plastic wheels tend to pick up dirt easily and carry it around your track, they will also cause drag and derailments, along with wheel wobble its also easy to deform the axles
Track cleaning needs to be carried out more often.
) and I've found that the advantages of metal over plastic are as follows: Metal wheels generally roll better, so you can tack on a few more cars if you want to. Metal wheels are less prone to issues like wobbling, so the stay on the rails better. (Also because they are slightly heavier.) And, not only are they easier to clean the gunk off of when it builds up, they also tend to stay cleaner longer. Plastic wheels tend to be very hard to get clean and keep clean. I have plastic wheels that I can't get totally clean no matter what I do to them.
