I had this exact same issue with several sets of differential rings and I ended up switching over to another brand. I discovered this issue when I gave my car to a factory driver to check the overall setup of the car. First thing he did was check the differential settings. What he did was he firmly wrapped his hand around the wheel/spur gear and with his other hand turned the left wheel. A loud squealing sound came from the differential. Not only that I was shocked to see the differential slipping with ease.

He ended up tightening the differential until it stopped slipping. Which was great. However, the differential was not working properly. Very gritty and you can feel the differential had high and lows in its movement. He then took it apart, rebuilt the differential with new rings that I gave him. It improved slightly, but it still had the same issue. The he turned to me and said "rings are flexing, no good." He went ahead and built my differential with a set of Square RC mirror finish rings. He said "these are very hard and have no flex."

From that moment on, I've been using Square RC rings with amazing results.


Running a thrust bearing is the #1 upgrade for a differential, #2 differential rings, #3 ceramic diff balls.