while that maybe true about the gates belts. i'm sure there are some tolerances that belts fall within. now i'm not a belt engineer but I would think the rubber may have different shrink rates etc. last time I ran v belts was almost 20 years ago and maybe the tolerances are better now.

on another note, if v belts were great, the oems would still run them. you can transmit more power with a serpentine belt with less tension and less load on your bearings, less parasitic loss due to friction, and ultimately I think the serpentine belt will last longer.

these new style belts have undergone lots of hours of durability testing thanks to the oems and their search for efficiency.

I just got the 700 series compressor in and will get a comparison put up later this afternoon after I had a chance to measure it and compare it the 508 series.