I've seen several people mount em there Josh and never have any problems with vibration. If I were doing it, that's the exact place I'd mount mine as well.
i hear ya bama, no problems at all, in fact even running down a bumpy gravel road they don't bounce at all. built ford tough!!
If that fiberglass bar is vibrating at all, you've got bigger problems. That thing is part of the structure under the engine compartment.
lol the bar is fine. the lights just vibrated like crazy. i could tap them with my finger and theyd go nuts.
