Gates has gone the way of Moog. As in, selling a name for max profit while they run it into the ground. Like about everything nowdays, they used to be rubber, then rubber/synthetic blends, and now basically mostly EPDM and the like. Turns out natural rubber as better at basically everything than neoprene, at least for what we are looking for.
I haven't had to buy anything but a serpentine for a while, knock on wood. I would recommend, if you know the length, to look at heavy duty farm implement like John Deere dealerships or possibly industrial like at McMaster-Carr. Last time I bought a JD belt it was rubber, and solid. But that was 11 years ago, so all bets are off.
The serpentine belt I bought was a Gates for my 98 Dakota. Last year, to replace the factory original that was showing a few cracks on the rib side. I kept the original in my toolbox. The new belt was F'ing navy blue with a purple-ish tint on the rib side, felt grainy right out of the carboard sleeve, and I half expect it to disintegrate in 2 years. Gates quality! I will not be a loyal customer anymore to that name, just like Moog. No point.
