Aprilia Falco Drive Force Diagram Discussion

What if we want to set some land speed records? Maybe you only ride with ZX-12s and Hayabusas? Can we gear the bike up for some higher speeds? Let assume we can fit a 17 tooth countershaft sprocket on the bike.

In the graph above, we've dropped a few teeth in the rear, and added a few in the front. The bike should now hit the rev limiter in sixth gear at 200 mph. But it wont.

• Wind resistance will halt this bike near 161 mph in fifth gear. Shifting in to sixth at that point will drop the bike back to about 157 mph! The bike can't pull the gearing you've selected. We've managed to gain 1 mph, but sixth is only good for gas mileage now. At no point will it pull harder or faster in sixth than in fifth. In fact, its a fact of physics that this bike cannot pull any faster than where the ultimate force curve intersects the wind resistance curve. Power needed to overcome wind resistance increases as the cube of speed. It takes a lot of power to fight the wind. This is why aerodynamics is so important in setting speed records. It also explains why a ZX-12 may feel stronger than a Hayabusa, but have a lower top speed.
   
• In addition to not being much faster at the top end, the bike now accelerates slower in the lower gears too. All the curves have moved down the force axis. Additionally, you now need to slip your clutch to 19 mph to get it pulling. It'll wheelie less, if that was your concern.

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