This chart can be very useful for making the most of the powerband you've got. As a general rule-of-thumb, if your bike won't consistently pull redline in top gear, then you're overgeared. If it will, and seems like it still has more power to give, then you're undergeared. Even if your bike will pull redline in top gear, but your top speed is more than you think you'll ever use, you may wish to gear down a bit for better acceleration. Conversely, if the bike already has too explosive a powerband for you, you can gear it up a bit to tame it down a bit. The chart is very simple to use. Just take your existing sprocket sizes and find the point where they intersect on the chart to give you your current ratio. You can then look at other points to see how a change at the front or rear sprocket will affect your final drive ratio. A smaller front sprocket or bigger rear one will give less top speed, but better acceleration. A bigger front sprocket or smaller rear one will give better top speed, as long as the engine makes sufficient power to pull the gear. Finally, don't be confused by the fact that a ratio that's higher numerically is actually a lower gear ratio. In other words, you'll have quicker acceleration but less top speed (theoretically) with a 3.83 ratio than a 3.53 ratio. I hope you find this chart as useful as I do.
