Quote:
Originally Posted by 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 |
Mike,
Every time I have had a customer contact me regarding this issue, it has been due to an incorrectly assembled piston coupler. Please check the nut location on the piston set screw and confirm it is flush with the end, also that the set screw is completely bottomed out in the piston rod.
Having this incorrectly set results in the shifting plunger not being in the correct location, which results in the balls not being on the round OD of the plunger, and rather the ramp edge, enough to "ratchet" as you're seeing.
Feel free to email me at prosupport.
-Aren