I am wondering why they use such small cogs on a bike. Problem with that is as you get down below about 15 teeth, you cannot get precise steps to the next gear. For example, you can go 15 to 14 or 15 to 13. 15 to 14 is about a 7% difference. 15 to 13 is about a 14% difference. Now lets suppose instead they had cogs twice the size such as 30 replaces the 15 gear. Now you have twice as many choices. You can go from 30 to 29 (about 3.5%), 30 to 28 (about 7%), 30 to 27 (10%), 30 to 26 (about 14%)...
Where this method really shines is when you get down to about 12,11,10 teeth. Then you are forced to space the next gear about 10% away. With my system you could space very high gears within 5% of each other. For example, the 2nd highest gear on a bike could have a 21T cog and the top gear could be 20T, representing only a 5% difference. Cadence would drop from say 100 RPMs to 95 RPMs which someone could likely power thru much easier than a 10% increase.
Also, I suspect the larger gears are marginally more efficient in power transfer and should help extend chain life.
So is this a practical idea and if so, why don't bike manufacturers offer it?