Lower gearing : since you are chain driven , it would take a sprocket change , a bigger rear sprocket or smaller front sprocket or change both sprockets ---------I believe the way it works is you make a fraction of the front and rear sprockets , divide it out and that will tell you what you got now , Example 12/42 -- 12 divided by 42 equals 2.085 ratio , ----a 44 teeth rear /12 tooth front would put you at .2727 ----count the teeth on your front and rear sprockets