Under rare, specific conditions, the handlebar on a bike can start to exhibit something called "speed wobble", where the handlebars will vibrate. First off, make sure your EdgeRunner has a handlebar stabilizing spring. This will greatly reduce steering issues and add resistance that will make steering easier. If you are still experiencing wobble, it can be easily remedied with a Cane Creek Viscoset: https://www.canecreek.com/products/headsets/viscoset
The ViscoSet offers viscous damping that inhibits these vibrations. The Xtracycle team has tried this on an EdgeRunner and it resolved the issue for us.
Have additional questions about your bike and issues you are experiencing? Drop us a line at firstname.lastname@example.org and we'll get you all sorted out!