First time I did my belts, I let the tensioner springs load the belts, but forgot to tighten the bolts down that hold the tensioners in place. Much racket ensued when I started the Accra and drove it around the block before the tensioner bearings self destructed. By Divine intervention the belts did not slip. My point is that even the best designs are not idiot (me) proof. How good is that belt service paperwork?