what are the best gear ratios


Mt current gear ratios are 1 - 2.615 2 - 1.937 3 - 1.526 4 - 1.285 5 - 1.136 6 - 1.043. I was wondering what the best gear ratios are to put on ur bike.
If I understand you correctly, you are asking about gear ratios in terms of countershaft sprocket and drive sprocket!? The ratios you posted are transmission gears and remain constant. The ratio you can readily change is the final drive ratio [countershaft (front) sprocket to drive (rear) sprocket]. Stock teeth are 17 front/40 rear for an overall drive ratio of 2.353:1. [40 divided by 17 = 2.353] The "best" ratio depends on what you want it to do. You can see the effects of gearing changes in a chart I created here: Excel Hayabusa Gearing Chart

Just change the front or rear sprocket teeth values in the chart's pink cells and you can see the effects on ratios, speed, RPM, etc. A lot of people just install a smaller front sprocket (16 teeth) with the stock 40 tooth rear sprocket for better acceleration (and a little less top speed) but there are many, many possible combinations. Play with the chart to see which effects suit your riding style. ;)
I'll take a shot at your question although I have not tried that particular combination. Since a 16T front sprocket is slightly smaller and a 42 tooth rear is slightly larger, you should be able to use the stock 112 link chain although you might loose some wheelbase length in the process (through chain adjustment). You'll be the new wheelie king with that ratio...! :super:
chart is real good, but calculates a little high. Looks like it does not take in the toatal circ. with the tire. 18/40 for example should be around 212mph chart came out about 223mph. Although I may have missed something.
Ninja Eater - Interesting observation! :) If you could run your input figures again, take a screenshot of the chart, and email it to me, I'll try to figure out where any discrepencies might exist between the 212 MPH/223 MPH numbers that you mentioned (or just tell me what figures you entered in addition to your sprocket sizes). The formula assumes a specific tire circumference based upon typical sport bike tire sizes, but allows the user to vary that circumference via the "Tire Depth (%)" cell to compensate for wear. As you know, significant differences in circumference are possible between a new tire with its tall curvature and the same tire worn flat in the center. Also, all tire manufacturers do not follow the same design formula for overall circumference with respect to tire size and aspect ratio. The chart does not consider the variables of side wall strength, tire pressure, tire expansion at high RPM, nor tire slippage since those factors are rather elusive.

The chart would be better if it simply allowed the user to measure and input his own circumference although even that would be subject to the accuracy of circumferential measurement. Because of thses kinky issues, I view the chart data as relative, ball-park information rather than empirical data.

Thanks for your input.    :beerchug:
Primary Drive Ratio 1.596 (KPH) (KPH) (KPH)
1st Gear Ratio 2.615 9.275 0 135 135
2nd Gear Ratio 1.937 6.870 34 182 182
3rd Gear Ratio 1.526 5.412 43 231 231
4th Gear Ratio 1.285 4.557 51 274 274
5th Gear Ratio 1.136 4.029 57 310 310
6th Gear Ratio 1.043 3.699 63 338 338
Front Sprocket (Teeth) 18 2.222
Rear Sprocket (Teeth) 40
Wheel Rim Size (Inches) 17
Tire Width (MM) 190 Gear (MPH) (MPH) (MPH)
Tire Depth (%) 48 1st Gear 0 84 84
Engine Minimum RPM 2,000 2nd Gear 21 114 114
Engine Maximum RPM 10,800 3rd Gear 27 144 144
Change Down RPM 4,000 4th Gear 32 171 171
Change Up RPM 8,000 5th Gear 36 194 194
Maximum Power RPM 10,800 6th Gear 39 211 211

ratios are all fine 10800 Max rpm 48% wear which would be about 76.75 circ handy chart. Should have percentage of tire whear and total circ. then it would be very accurate. You should be able to put in wind resistance to I would think with the right formulas.
Excluding wind resistance (which YOU can tackle if you like), I'm sure you have a point but I'm not sure what it is...
The point is it is a good chart. Accurate except for the circ. of the rim and tire. Shold give most of the info that you would need.
10-4 It can be saved and all parameters revised/edited for custom purposes by anyone who wants to do so.