I have a 1997 Schwinn Mesa that I want to put a wider set of handlebars on. I do not really want to replace the threaded headset and would like to keep the original stem. I need some help finding out what size of handlebar I can use. I am somewhat new to mountain biking and can use any help I can get. All I can find online about the handlebars size is on Bikepedia and it is listed as Hsin Lung MTS 309.