Hey. The +4 will have no affect on gearing. As for flying up the hills, that costs lots of money. If you have 22" tires on the back a 13 tooth front may be the ticket. As I said before with my dune port stock stroke motor I ran 13-40 gearing with 22" tires. Another issue could be weight. You might need to set her up for your weight. Tuning these bikes takes time to get it set up for you, every thing you do changes the bike. I'm always messing with gearing, I just changed to 14-39. That seems to work good for me.