Just bought a new Shark RSI helmet. Its a good snug fit and I have no problems with it other than when I get a bit of a spurt along, the whole helmet vibrates so badly that I dont get good straight vision. Never had this problem with other cheaper brands Ive owned. Hubby said its got something to do with the angle of my windshield causing the wind to hit the helmet, but we've tried a few angles with only limited success. Any ideas?