🔧 WINSINN GT2 Idler Pulley Pack of 5 - 20 Toothless 5mm Bore Aluminum Timing Pulley Wheel for 3D Printer Review

I bought 10 of these tensioners (2 packs of 5), I need 4 for my assembly. Unfortunately, out of 10 good pulleys, only TWO were, so 80% of the marriage. The bearings used are of terrible quality and do not rotate smoothly, it requires hand strength to rotate. They can't be turned by a belt in my car. The bore size of my pulleys was 7.9mm which made the parts unable to hold my 8mm shafts. I had to hammer the shafts through the bearings, which made them even more inept. be rotated.

**Update** After about 50 hours of pushing with each bearing 3 of them have failed. I'm not printing at high speed and the Y and X bearings are failing. The bearings are not the best as mentioned in other reviews. If you are using them on a 3D printer you will need 3mm bushings or spacers as there is no flange at all on the bearing bush. I've found that the screw pulls out a bit when you move it, so using a lock nut is also recommended. Being a toothy slacker, I don't think it matters for print

I can't believe I did myself a disservice by purchasing these parts. I'm causing an unknown problem on my printer with poor print quality until I realize I'm having a lot of vibration from these GT2 idler pulleys. The bearing was so bad it looked like it was made out of a square bearing and not a round one. Also, the rim wobbles a lot, causing the belt to move up and down. Out of 10 I bought only 1 seems to spin smoothly but not perfectly. Folks, before you put these things in your car, be sure