I am very happy with my Batribike Dash folding bike except for the gearing. I think it is too low geared. Even in sixth gear on minimum assist, when I get to a certain speed my legs are treading air. Has anyone else had this problem? I read in a bike review of the Batribike Breeze that this was the same for most of the small wheeled folding bikes on the market. Someone commented on this review and said he had fitted a larger crank on his Breeze and that this had cured the problem. Does anyone know how this is done and the implications with regard to the guarantee?