Thanks for the replies guys. Looking in my parts bin, the largest gear I could find was a 39 tooth and the smallest is a 22. It would be good to use what I already have, that would work, if I could. So what could I use to make the 39 tooth gear work. This way I only have to buy one gear. If I could come up with an 18 or 17 tooth, would this work. As for the chain, I have a few to choose from, 64 link and 66 link. That will obviously depend on the gearing. I don't want to get too crazy with the low gearing as I still want to play a bit in the powder with this sled. Sorry for all the gearing questions but when it come to gearing and clutching I have limited experience.