That's interesting. So, mushroomed, or peened, heads on both sides? I've wondered before just how they do that and keep the rod from peening evenly. Just a guess but looks as though the roller is just too tight in the assembly. Only thing I can think of is remove the rod, grind down the roller end and replace the rod. But, with what? Looks like the roller is chrome plated. Trying to remove some off the end of it while in the frame would be tricky. But might work.