Do know if you care, but you might want to consider the # of skid patches when making your gearing changes. I have found this to be very useful because I hate having to drop a ton of money on new tires. http://www.bikeforums.net/showthread...t=Skid+Patches

I use this table all of the time. It allows you to alter it depending on certain variables (tire size). http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3521 Click on Gear Tables (.XLS 227KB) for an XL spreadsheet.