If it's minimal maintenance you're after, these quality PVC belts with impregnanted lubrication require less attention to make things run smoothly.
This Sportsmith running belt fits Horizon Fitness DT850 treadmills, Serial# TM166*
User facing surface: Black Diamond
User facing material: PVC
Impregnated Lubrication
No need to apply lube during belt replacement

Finger-spliced seam
1 ply
*Some units with the same name use different parts. This is why you should always match your model# or serial#.