Wangdd225PCS GT2 Timing Belt Idler Pulley ( 20 teeth ) 20T Aluminum Bore 5mm With Bearing For 3D Printer Accessories Belt Width 6mm

So i purchased these in hope of removing some additional visible lines in my X and Y directions. In theory it would help the belt run smoother by allowing the ribs of the belt mate with the teeth on the pulley versus rolling over the flat face of the stock pulley. After receiving these, I inspected and tested the smoothness of the bearings. If you take the tip of a small touch paint brush or even the tip of a pen, you can feel the smoothness. 4 out of 5 were rough, not binding but noticeably not as smooth as the used original ones I just removed. I applied bearing oil(RC car specific) to bearings and worked it in, that cleaned up about half of them, the others it didnt make a difference. I then installed them on the X and Y axis belt tensioners. This is where you will notice they do Not fit well on the Ender3V2. These pulleys measure aprox 12.2mm on the diameter(its actually smaller than that since the belt rides in the teeth of the pulley) and aprox 8.5mm(1.5mm narrower than stock pulley, which will allow the pulley to walk side to side) from outer flange face to face. On the E3V2- the X pulley measures 16mm dia and 10mm wide, Y pulley measures 13mm dia and 10mm wide. Also the bore of the pulley is M3(E3V2) versus M5 on these pulleys. Once you combine all the differences in sizes and actually install it, your belts will rub on the aluminum 20x20 bars, because of the decreased daimeter of the pulleys. So I am giving them a 3/5 stars due to the poor quality of the bearings. They will work as a last resort, so I will hold them for spares, just in case.

Edit to my first review: after receiving new bearings to replace the ones in these idlers, I found that the bearings themselves are defective and POSSIBLY may not be a result of bad pressing, therefore, I am increasing from one star to three as they are pretty rough, but may not be the fault from assembly. The pulleys themselves are good and concentric.Stick in a shaft and rotate, feels like its grinding, its the same with all 20 that I purchased.Its quite obvious that they were pressed into the pulley from the inner race and not the outer. Pressing from the inner race puts all the force onto the balls causing flat spots on the balls and the race resulting in rough rotation.On the other hand, the machining is pretty nice, but the poor assembly is pretty sad to me.I would NOT recommend buying these, thoughtful assembly by the manufacturer is apparently not a concern.Unfortunately, I will now have to somehow remove the bearings and replace them with new ones, as i'm sure replacements will result in the same situation. :(

Not as bad as I feared from other reviews. Ordered 10 to make sure I would have enough "GOOD" ones due to other reviews stating bad bearings. Mine all came with good bearings that are smooth and work just fine. I wonder if others are tightening the axle screws down too much causing problems with side load on the bearings making them grind?

They appear to be nicely made. I replaced my TEVO Black Widow Y axis idler pulley (without teeth) with this toothed pulley in hopes that I can get rid of some Y axis inconsistency. I also made a few other minor modifications to both hardware and firmware so I can't tell exactly how much this pulley helped, but I can say for sure that my print quality improved. The Y axis is now much smoother and I suspect this pulley has something to do with the improvement.

just what I was looking for

Used for X and Y axis idler pulleys on an Ender 3 3D printer. Works terrific and is toothed properly for the belts. I wanted the toothed pulley so that a flat one doesn't wear down the teeth over time. I actually used them for a printed bracket I made that spaces the belt up a few mm so it doesn't come in contact with the X/Y rails.

These bearings are much better than the quiwi or whatever they are called also sold here in amazon. The bearings were bad and the machining was out of round and not concentric to the bearings.These however did not showed any of those problems. All 5 bearings were great! And moved smoothly once installed. I highly recommend these!

Bad bearings on 4 out of 10 that I purchased. Very poor qualityEdit: Great Customer Service!!!Wangdd22 was very quick to respond and sent replacements for the bad ones immediately.Thank You very much for your fast response.Just received my third order, and all pulleys worked great!!