We use HTD series belts and plastic pulleys from
www.econobelt.com We also use Aluminum pulleys for low tooth count (actually lighter than plastic) or when we need to do a large bore. Shipping has always been acceptable for FRC build schedule. Price is not to bad. We have yet to have any failures of these on our swerve drive. In 2011 we stripped the belts with our arm. That was our fault, not the belt.