Saipor 2GT Aluminum Timing Belt Idler Pulley (5pcs) Synchronous Wheel 20T 5mm Bore for 6mm Width Timing Belt, 3D Printer Accessories (20T, Bore 5mm, W 6mm, Toothless)

I bought these for my 3d printer. I've already had 1 fail after about 20hrs of printing. The bearing has a lot of play in it and started squeaking. I replaced the bearing but it now seems like one on another axis is also going the same way.

Sadly i cannot recommend these pulleys. I purchased them to use on the x-axis of my Anet A8 3D printer. Its been used a lot over the past few weeks and I've had four bearing failures. Each bearing has lasted about 25-30 hours of actual printing time. I have an adjustable tensioner on this axis and initially I thought I'd got the tension set too high, so i turned it down after the first failure but that didn't stop another three failing. I'm going to use the last one I have to repair the printer so I can make an idle pulley mount that can take more substantial bearings.

These are the second brand of these bought for a 3d printer, and again the bearings have all failed within a few hours of printing. Avoid.

Not good sides are tooooo large