4 stroke on a 29 cruiser - rear sprocket?

I must have a 5.1 ratio transmission. I had to take it off last night. Out of curiosity I spun the front sprocket and the little gear turns 5 times to its one time. Did the calculator and bam! 26.9 mph at 7800 rpm. So am I running a 25.1 ratio going off those calculations? IF so, changing the front sprocket to a 12t (from 10t) would put me where I want to be for cruising speeds. I would rather change the front sprocket due to the rear sprocket of course is a *****. Or is changing out the rear sprocket ideal?