Not 100% sure yet on the ratio Dave. The original small pulley I bought gave a 4:1 ratio but with the increased brushless shaft size of 8mm, that pulley is too small in diameter to fit grub screws into for securing in place. So I've yet to buy a new one (gonna have a look on Technobots shortly) but will probably aim nearer to a 2.5:1. Think Boner ran that ratio at the champs and seemed fine, and this drum is almost 2kg lighter.