why does my tread mill smell like it is burning rubber?

It could be a loose drive belt. If it’s loose each time you step it slips a little. The belt will get hot and start to kind of melt. If you belt and deck is worn the high amperage draw by the motor can melt the insulation of the wiring. This smells funny also. You can tighten the motor if the belt isn't worn to bad. Replace the belt and deck

Mark Peterson
February 2008