I just pulled into a RV Park in Columbia Falls, Montana. One of the staff was helping me line up my Reflection and noticed a black substance on my trailer rims. He said that he heard this could be a problem and suggested I get some advice from a RV Mechanic locally. I mentioned this to a RV dealer service location several months ago but they indicated it wasn't a problem. Of course there was only a little then and only on one side. Now there is much more on all four rims and a lot of it since I left the last park 150 miles ago.

Does anyone have any experience with this issue? I have driven the Coach about 2000 miles now plus the delivery from Indiana to California-Arizona

Thanks