Ok, 15t fit and quick test accomplished. I like this mod, in fact the bike probably should have come this way from the factory. Some findings from a brief road test both on and off road.... - Much better start off from full stop. Don’t have to rev the engine as much to get rolling and less tendency for the bike to feel like it is going to stall. Almost feels like I have a bigger flywheel. More tractor less two stroke. - In high speed riding, there is indeed a 275-300 rpm difference noted at common cruising speed...55-62mph. Also noticed maybe a little more buzz in the seat area. Could this be from odd/even sprockets? I only got up to 62 mph on our deer infested roads so I’m not sure how freeway speeds will be but with such a small RPM increase, I doubt it will make any difference in rideability. -Roll on in 5th and 6th gear feels better. - In low speed riding, I feel like I have reduced the lower limit of confidante low speed handling from 9 to 7mph. This makes a big difference when trying to crawl up loose surface hills. Didnt feel the need to feather the clutch as much. (Remember, short test ride of 5 miles paved to 3 miles two track. ) I was really looking for better low speed power and rideability and have found it with this simple mod! I see no reason not to do it. I’m going to ride around like this for awhile and continue testing. Not sure when I’ll try the 41 rear.