Comments: - - Your max speed is always going to be limited by aerodynamic drag vs. power input. When the drag equals the available power there will be no further acceleration and that's your top speed. I should say "your theoretical top speed" because if your gearing is too low or too high you may not be able to reach that top speed. This applies to all vehicles, not just human powered vehicles, including aircraft. When drag equals power, you don't go any faster. I once owned a car with 147 hp and a ridiculously high top gear which would give 180 mph at the 6000 rpm redline. Needless to say the car would never reach the redline in top gear or go anywhere near 180 mph, unless it were driven on the moon where there's no air resistance.
Looks like a bit of fun especially on down hills :) , it might be a bit hard on the knee joints on the flat though , but as others have said electric assist would make it really cool. Very clever making the gear mate , 10 points for innovation .
I've studied on bike gear ratios for a long time and i'll drop my 2 cents. First of all there is a point where depending on its ratio, a huge gear might be beneficial as the longer you pedal the more torque you can produce at lower RPM but NOT significantly more horsepower which determines top speed, but it depends on the rider and the conditions of the road, tire pressure, saddle height and ride's mood. Most times if you are used to it you can achieve the same speed with much lower crank RPM than your lowest gear ratio, but even a slight slope can take away the benefits of riding calmly. I've used to have a top speed of around 50-52kph on a 26" mountain bike with 42t front gear, changed to 48t but regardless if some gears can come close to what they where with 42t, the effort it takes to accelerate or going over a slope or hill took away my physical ability to maintain as high speeds as with 42t even with the stamina being unchanged, however if i ride at lower speeds the effort it takes it's like i'm walking compared to revving the crap out of my legs for no reason. The only good solution for bike gearing is a CVT alike system like Nuvinci, because there are many factors that make the same gears not perform the same for a second time on the same cyclist, but all these come with many downsides. The rule is: Big gears = need more torque = high saddle height = decreased ability of high RPM = Less top speed. Decreased saddle height = Ability for more revving with high gear ratio = most times better acceleration and top speed = knee pain that lead to problems.
