I've only ever used Gates K081145 belts. Put them on 5 different SRT-6 motors with anywhere from an OEM pulley down to a 62mm SC pulley, even one with a 178mm crank pulley...never had a problem. Four of the five had some sort of pulley saver/belt wrap kit. One LM21 BWK (me), two DIY kits (Thumper, Kim), and a NW PSK (customer). All still run the belt I put on without issue.