9 tooth driver
a 25 tooth sprocket will fit on a 9 tooth driver
Any size will work. What'll work best depends on what you want it for. Higher top speed - go for a big sprocket. Quicker off the start - go for a smaller sprocket.
13t driver goes on a 33t sprocket
13 tooth front/ 40 tooth rear
41 tooth
Usually the sprocket is an inseparable part of the freewheel, and the size of the freewheel is determined by the hub.
It uses a 47 tooth sprocket.
There isn't much need to discuss tooth size as such. The important things are which width of chain the sprocket is intended for and the tooth count. Tooth count decides which gear ratio you get.
The difference between a 48 tooth and a 51 tooth sprocket primarily lies in their size and the resulting gear ratio. The 51 tooth sprocket will provide more torque and better acceleration due to its larger size, making it suitable for climbing or heavy loads. In contrast, the 48 tooth sprocket allows for higher top speeds but may sacrifice some acceleration. Ultimately, the choice between the two depends on the specific performance needs of the application.
you don't use a freewheel for a 23 tooth sprocket you need a cassette hub heres gear ratios for yaSprocketF/W or Cassette2282382592810301133123613391441154416
45 tooth rear
17 tooth front, 42 tooth rear, 110 link chain, size 530