I spent a little time building a spreadsheet to calculate differant speeds at differant engine speeds. It takes your current final gearing and your tire size into account, so this will work for all DRZ400's. Just edit the Front or Rear Sprocket Fields on the sheet!

[ATTACH]8085[/ATTACH]

Also note that this spreadsheet will work for any bike that you know all reduction ratio's.

BTW, a big thanks to William for supplying the transmission ratio's.