Anyone got a formula to hand for drive belt length using different size pulleys. Nasty messy looking calculation - probably trivial once derived. (Circ_P1 + Circ_P2)/2 + 2 x Centre_Distance) is a bit rough for large diameter differences. RM -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads