For those interested in gearing and what happens to your bike when you increase the rear by +2 , change from a 180 to 190 rear or how far the rear wheel moves when you change the sprocket .. even gives you the chain lengths ... type in the details and it gives you plenty of info .

http://gearingcommander.com/

Just select your bike make and model from the drop down menu and edit your current settings and custom settings.. plenty to play with here..