Howlin,
What kind do you have. You said corless so the're only a few. I run a Beltronics, with flat units of velcro. It never moves evern at up to 189mph. You will have plenty of room on the flat between the bars. I also run a GPS with velco. for reasurance i keep a safy strap from the bars to the units.\, but never needed them yet. Always a first time so keep them safe.