bought a 535 afew months ago to return to biking after 30 years ,lovely looking bike ,but is revving its head off at motorway speed,am always looking for another gear,not much you can do about it with a shaft drive ,unless you could fit a larger back rim or change gears ratio`s in the box ,neither of which would really be practical ,think it`s something you will have to live ,as i do till i get around to changing it for something with a bit more go in it