In general, the lower the ratio the higher the top end, a higher ratio is for torque. The best way to understand it is to apply it to a bicycle. If you change the sprocket in front to the smallest and the rear to the largest (like going up a hill) you have good torque but poor top end. Large in the front and small in the rear (going down a hill) good top end but poor torque (legs are not strong enough if a hill appears). On a motorcycle the trick is to find the sweet spot that balances the two with regard to engine power. Most of our bikes are geared for duel sport riding, 14T to 15T in the front and 48T or higher in the rear. There is gearing in the transmission that effects it all also. Again, our bikes tend to have high ratios for the first gear that causes us to shift quickly (with stock gearing) on the street but works well off road. Forchetto started this post that helps with this also.

http://www.mychinamoto.com/forums/sh...ight=sprockets