I have recently found an RV6A to acquire, everything checks out so far except for the nose gear tire shimmies when landing on hard surface, grass is fine, the plane has not flown much in a couple years, 3hrs +/- per year, parked on concrete, nose gear torque is correct according to Vans, air pressure has be varied from 20PSI- 35PSI, the discussion has now turned to hard spots in the tires, it has an 11-400X5 6 ply tire on it now, it seems like one of the available tires comes from afar country and I don’t spend my money on their stuff, can any suggest the best American made tire and a source for said tire.