For me the six speed was to give me a better low end while maintaining that highway gear. I have a six speed with the over drive and the close ratio low end. its a good 300 rpms different on the top end and put 1 2 3 together to give me a nice hole shot. not that I ever do that. I have a six speed for sale if anyone is interested they are very reasonable. more than you'd think. this one has a solid warranty too. with all the papers. I sell parts on the side, let me know if you are interested.

 

You get an extra gear with the 6 speed....2 extra with the 7 speed. You don't have to use them if you don't want to. But you get a higher top end at lower rpm = more comfort & flexibility. FWIW, my 1974 Yamaha RD350 had a six speed. Kind of strange to think it took HD over 30 years to add 6 speeds to their bikes. Wellmost of their bikes. Even a Chevy Suburban now has a 6 speed automatic. I traded my Sportster in largely due to the 6 speed on the dyna.

 

07 Ultra (6 Speed) I get 45 MPG @ 60 MPH using cruise control; rpm is slightly over 2K. That's the advantage of a 6 speed, torque is nothing to brag about but I believe itprovidesexcellent gas mileage. Like someone said, you don't have to use it but having it available is great.

I'm sure you realize that 6 speeds on performance bikes are for an entirely different reason. They keep the engine close to the performance curve when shifting. With the C.I. on the Harley, the engine has a flat torque curve sothe gearing can be broader and it is; it can pull over a broader range of RPM.