No wonder why worn belt tensioners get noisy!!

I had the old belt tensioner out and apart for inspection, here is what I found.

The main body of the belt tensioner, with large 12mm hex center bolt, is retained by ball bearings. The ball bearings are seated between an outer race and an inner race around the large 12mm bolt. Both inner and outer races had a deep wear spot from each ball bearing, adding space between ball, and both races, as much as 4 mm, or more, of space. This is what I was hearing! Click click, clack, click..................

The shock absorber, belt wheel, were OK. But if the 12mm center bolt and bearings were to be let go without replacement, I would imagine the belt would slip off the wheel at some point, but I'd bet I could go another 5k or 10k before the belt would come off!