I have a 19 Rebel with 42000 miles. I started to notice that the rear shudders over bumps. I threw a set of 5100 Bilsteins on it. The ride is a little more firm, but it still does it. There's nothing loose or worn out. I started noticing it after I had a Leer cap installed. It's only a couple hundred pounds. I'm just wondering if the weight of it and it being the size of the bed if it's related somehow. I really don't want to pull it off to see. It's just annoying because now I'm paying attention to it..