A lot of aftermarket parts come with a lifetime warranty. A lot of OEM parts are manufactured by aftermarket companies, often the same one that supplied the factory. Which is then the better buy?
If you pay attention to your car and visually inspect your belt every 10k miles or so (which you ought to in any case) you won’t be getting any nasty surprises. Heck, for the cost difference you could replace the thing every 30k miles and be ahead of the game. It’s not likely you’d have to replace it that often, but you could if you wanted to. Just to be sure it never fails when you don’t want it to.
To be honest, I am a former employee of Dayco Products, Inc. and have spent time in their plant in Williston, South Carolina which, by the way, is one of the nation’s largest producers of serpintine belts. I saw OEM belts produced on the same lines, using the same materials and processes as replacement belts. Trust me, they have different labels !!!
My experience has been that the cheap, off-brand belts get glazed on the top (non-ribbed) side and start squealing fairly quickly (at least they did on my old Ford truck). A higher quality belt (like the Gates or Dayco mentioned before) tends to last a lot longer, and is still cheaper than going to the dealer. BTW, save the old belt you replace and keep it in the vehicle somewhere for emergency use. It may be worn, but it will most likely get you home if the replacement should happen to break on the road sometime.
Maybe I should be more specific. When I worked for Dayco Products as a quality control technician, I made the observation that most belts were made on the same line, with the same material, and using the same prcocesses. Everything was in place. If, for instance, GM had ordered GM OEM parts, the GM OEM label was put on the sleeve before it was sent to the vulcanizer. If GM had ordered GM aftermarket parts, the GMAC label was put on the sleeve, or if the order were from a private name like Pepboys, the Pepboys label would be put on the sleeve. Sometimes, if there were not enough orders we might put a Dayco label on the sleeve. Granted, this is only how I saw it done, but I haven’t been in one of their factories in a decade. Something might have changed.
No I understood you, but perhaps Billy Bob’s gun, tackle and belt company is also making belts for these companies too, the only way to ensure you get a dayco belt is to get a dayco belt, and for that matter, the only way to ensure you get a billy bob’s belt is to get a billy bob’s.