When I mount my V1 on the windshield, and I carefully set it as straight as possible, then I hit a bump on the highways, it slides down. I have to constantly have to re-adjust the V1. This is annoying as my RL has never had this type of problem. It's dangerous for me to re-adjust the V1 constantly to be straight, due to the fact that I'm on the highway. What is the best way to fix this problem?