You will find the atmosphere to be fun and the weather is normally very good. Like they said you will see lots of plain old ordinary Harley riders (RUBS or otherwise) a smattering representation of OMG outfits like the HA, Outlaws and others. last year there was some trouble between the HA and the Outlaws in Custer State Park.
(A shooting between the two gangs.)
fortunately those idjits represent only themselves and as long as you stay away from them you will be fine. They all have a misguided idea of their own owed RESPECT and they take that misguided idea very seriously.
The views in the Black Hills are great. Lots of nice two lane roads.
Check out the Stone House Saloon in beautiful downtown Belle Fourche just up the road aways from Sturgis.
I may make it myself this year as I dont have to worry about lodging. I have a brother in Piedmont and a sister in Rapid City.
