[Henry Schmidt]

The design of the "safety collar" is not to prevent tensioner failure. It is designed to alert the user to a failed tensioner. If you pay careful attention the your engine sounds, the safety collar will make a knocking noise on start-up after the tensioner fails. If you ignore the noise or just aren't in tune with your engine sounds, the collar can cause damage if perpetually exposed to stresses/ pounding.

If you're looking for a tensioner safe-guard, you can install a Teflon or Delrin collar [6-7 mm] that will prevent engine damage from tensioner failure. It will not alert you to the failure but it can save your engine.