I personally have never had any luck with aftermarket belts. I always use OEM. An aftermarket belt has to be different from the OE in some way. Angle , length etc.... Not saying they aren,t any good! They just need some clutch adjusting to make them work. I have some friends that use aftermarket and are happy with them . You just can,t mix OE and aftermarket , your spare has to be same as whats on the sled .