For those of you who are trying to decide if you want Underdrive pullies I offer up this alternative. I didn't want any of the problems associated with a complete set of UD pullies. So for $49 I bought just the WP pulley from Motoblue. My butt dyno is well tuned and I could tell it had more past 3,500rpms. No to mention since my crank pulley is stock it isn't underdriven enough to overheat.