Ball Shifter High Gear Issues

[Mike Marandola]

All season we have been using the 60:24 3rd stage gear set (8.4 fps actual) on 2 CIM VEXpro ball shifters and decided to speed it up in the off season. We had no turning or stopping issues, it was just extremely slow. A few months ago we were planning to testing the 54:30 set but they were out of stock. We ended up ordering the 50:34 kit just to try out even though we knew it would be too fast for 2 CIMs. Low gear was fine, but in high gear we couldn't turn while moving forward or do a hard stop without hearing a loud ratcheting noise. We didn't have the time to find the cause before our off season events so we switched back to the 60:24 set. Tonight we swapped in the 30:54 gear set to give us 12.6 free speed. While not nearly as bad, the ratcheting was still occurring. We could at least turn while moving but we still couldn't do a hard stop and reverse. I found a way around this by shifting into low right before coming to a hard stop, then shifting back into high to accelerate in the opposite direction. We thought that the shifting plunger might not be engaging but I taped my phone to the robot and saw that it was fully in gear when making the noise. What exactly is this noise? Is this normal? Do 4 CIMs simply not have enough power to turn and stop at these ratios?

Robot specs:
134 pounds
AM14U with 2 CIM VEXpro ball shifters
4 inch HiGrip wheels

Here is a video of our testing