I've been looking for a X3 belt drive conversion for some time because I would like a broader rpm range for this machine. Something similar to the X2 would be preferable. I'm away from home for about another month so designing the conversion myself before school starts up again would be a bit of a problem. Also, I am not sure how to find the way to figure out what the proper size of pulleys I would need and how I would go about making them. The biggest problem wouldnt be the pulleys, I know how to machine those, it would be the keyways which are a mistery to me. And yes, I have seen the "ArcEuroTrade.Com" pdf file but I would like to get rid of the gears so that I can expand the rpm range and quite the machine. Any suggestions. Thx