Woody,
I am going to disagree with you on the belt lengths. According to the chart from your earlier post the 4081150 is 114.5/115.3 and the 4081153 is 115.3/116.1. (I am doing this from memory so dont flame me too bad if I got a number wrong)
I took everything apart last night to install the 115.3 Gatorback and then couldnt find the sucker. I hate it when I try to get organized. I put everything back to gether and then while cleaning up and putting things away, I literally bumped into the belt hanging on a rack(that I looked a 4 time for the belt). I wasnt in the mood to tear it all down again so I will do it today. I will get the measurements of both the factory and the 1153 belt and pics of the position of the tensioner pulley.
It sounds like we may have found the culprit with the rating of the bearing though. Both NSK and Timkin are very good bearings. But if we are operating them outside of the rated spec, we are going to have failures. It's just a matter of when.

Jerry,
When you find a higher rated bearing, could/will you be offering the ideler pulley as a 'high speed' option pulley? I would like to swap mine out for a higher rated bearing pulley before I have issues.

MikeR

Edit: data from Woody's Goodyear link.

PART NUMBER METRIC PART NO. NO RIBS EFFECTIVE LENGTH OUTSIDE LENGTH
4081145 8PK2910 8 114.5 115.25
4081153 8PK2930 8 115.35 116.05