How to Replace the Rear Roller on a Treadmill. Horizon Fitness Updated August 26, 2021 17:18 Please see the attached PDF for instructions on how to replace the rear roller on your Horizon Treadmill. For assistance, please call 888.878.9011 or email firstname.lastname@example.org. To order replacement parts, visit parts.horizonfitness.com or email email@example.com. Replacing Rear Rollers on a Treadmill.pdf20 KB Was this article helpful? Yes No 0 out of 0 found this helpful Have more questions? Submit a request Related articles How to Fix a Loose Treadmill Running Belt How Do I Fix Resistance Issues on a Treadmill? Comments 0 comments Article is closed for comments.