Stock size handlebars are 7/8″. Most ruckus tree handlebar stems will fit a maddog. Some may require you to shave down the top of your battery box if they rub. Others may need a shim. It’s hard to promise what will work when these bikes are from China and each one is unique. For the most part however the ruckus stem you find should bolt right onto a maddog. Keep in mind if you go ape hangers you will need longer brake and throttle cables.