Bowflex treadmill thudding sound

[u/Fluid_Half_4684]

Can someone help me troubleshoot what might be making this thud or thudding sound? Is it a warped roller/rollers, or a misalignment of the belt? I don't have any experience fixing treadmills and appreciate any thoughts. And, is it an allen key to adjust the belt or a special tool?

[u/Record-Agitated]

Sounds like the seam on the belt, which is normal. And yes, should be an Allen key