I was considering changing the final transmission ratio for some time, but as i've put a 190/55 in the back, it became a must for two reasons:

1. the chain beeing too short the tyre is rubbing on the swingarm
2. the dunlop gp is very tall, and the bike feels low on torque

So i.ve ordered a 15/45 530 kit. Next week i'll have it fixed on. I hope it is a good choice. Will informe you.

 

I change to 15/42 ...better than b4