Review on Befenybay 2020 Upgrade: X-Axis Synchronous Belt Tensioner For Creality Ender-3/Ender3 Pro/Ender3 V2/CR-10/CR-10 V2/CR-10 V3/CR-20 Pro –Straighten And Stretch For Enhanced Performance by Jesse Blair

I'm getting kind of tired of buying all these poorly designed upgrades that on the surface seem like a good idea but once you get them you realize that they are very poorly engineered.The main problem with this belt tensioner is that it has less than half the travel adjustment of the stock tensioner.I believe I measured close to 20 mm of travel adjustment on the stock tensioner while this new and improved upgraded tensioner barely has 7 millimeters of adjustment travel.You would literally have to redesign the entire thing to get it more travel out of it.You could try to adjust travel by adjusting its position on the 20x20 extrusion but the problem with that is that the short side needs to be butted up against the extrusion on the other side or you wind up with excessive flex in the aluminum far more than in the stock part.In other words by only supporting it on one side the entire tensioner flexes while the tool head changes direction. This might not be a problem if you're printing it slow speeds but when you crank up the acceleration to 1500 and the prints meet up to 100 mm a second you can literally see the tensioner bending back and forth.This means you have no choice but to butt it up solidly against the 20x20 extrusion so both sides of the tensioner are supported.If you don't you'll wind up with excessive ringing in your prints.The primary flaw in this design is they engineered it so you can replace the belt without having to remove the idler pulley. This meant increasing the distance between the back of the idler pulley and the threaded adjustment plate. This severely reduced travel adjustment.On the stock Creality printer you actually have to remove the idler pulley to replace the belt and while this may seem inconvenient the benefit is increased travel adjustment.Of course the manufacturer could easily solve this issue by making the plates on either side 11 mm longer so you have the same amount of travel adjustment as the stock unit.The bottom line is this just means you're going to have to replace belts more often. Even on a brand new stock belt I'm within 1 mm of the maximum travel of the adjuster, the only choice I have is shortening the belt by about 5 or 6 mm