Pal Paul in S. Africa has just purchased a Karate Monkey. He had some questions about Dingle drivetrains (2 rings, 2 cogs, no shifting). I mentioned that his 8 tooth differential was probably overkill, and that in my experience running a 4 tooth total differential (34/32t rings and 16/18t cogs, for example) should be more than enough. Of course, I've never been to his part of the world. Paul writes: "I know I'm always telling you how extreme stuff is here (and I have a few stories at the moment) but listen here. This time of year our strong southeasters…