For anybody who’s ever used a screwdriver to slip a belt onto a pulley, you’ll recognize how Snap-on’s stretch belt tool works. In the brochure at the bottom of the post, they claim you can use the tool for mounting belts on some late model Ford Chevy and GMC SUV’s, but frankly I don’t see what would prevent you from using the tool on other vehicles.
The Chinese-made tool fits over the lip of the pulley and a special bolt holds it in place. When the tool is in place you can rotate the belt onto the pulley in tight quarters without twisting the belt.
A search at Snap-on.com shows pricing at $13.
Stretch Belt Tool (PDF) [Snap-On]