just do the math sir...
44 Divided by 15 = 2.93
2.93 will be your gear ratio. The higher the ratio, more accelaration you will be getting for your bike, but you will sacrifice your top speed.
Tyre size must be take into consideration as well
- Since you have a stock engine, IMHO best combi for City and Long drive is 15 40 with 90/80-17 front and rear tyre
15 40 will be giving you a 2.66 ratio
HTH
Ride Safe