Theres a product called 303 Protectant thats made to rejuventate pretty much all rubber and plastic, it also works well on leather and fabric. It preserves and adds UV protection. I wouldnt use it on synthetic bar tape cause it can be a bit slippery but on leather tape i think it'd work well. By the way this stuff is great for softening up old rubber brake hoods and no i don't own the company
