It's solitary oak leaf miner. It's a tiny catapillar that feeds on the vascular tissue in the leaves. It will kill off a bunch of leaves, but 99% of the time, the tree will recover from the leaf loss. The Georgia extension service has a good article on their website about it.
Yes road and mountain. I didn't ware spandex untill I started racing and riding with professional riders. At that point I needed every little bit of help I could get. Only ware spandex on road and mountain bikes races.