Hi, it's Cindy from Crucial Vacuum,
Your Bissell 9200 Proheat 2x vacuum's brushroll is connected to the motor by two different sized geared belts. Over time, the belt's gears wear down and stretch out losing the grooves and tension that turn the roller. Another cause could be there is debris stuck on the roller and/or bearings. To gain access to your belts and check the source of the problem, please refer to page 15 of your manual, a direct photo is attached.
You can purchase direct your replacement belts from Crucial Vacuum with free shipping and an exclusive 10% coupon for Fixya.com viewers, use code: FIXYA10
I hope this was helpful. If you would like further assistance, please feel free to give us a call at 877.750.9239. We have helpful and friendly customer care representatives on the line ready to assist you.
Crucial Vacuum Customer Care