Vex Planetary Carrier (versaplanetary)

Last month,

While taking apart a versaplanetary I have discovered the pins on the carrier have slipped out and has started scratching the back housing. This is a 10:1 versaplanetary. I have pressed the “pins” back in and plan to later on to come back and clean and add retaining compound.

images here: (images too large to upload directly)

Has anyone encounter this?


Hey Andrew,
You’ll be hard pressed to find someone why ran those gearboxes as hard as you guys did.

I think you guys were using the versa’s outside of their intended use. Running them in a drive-train is a bit much, even without a fully weighted frc spec robot.

The “mini bot” had no bumpers and was bashed around, with the wheels sticking out past the frame it’s just begging to give the versaplanetary an extra pounding. I’ve heard this thing does back flips against the chain link fence, which is awesome and all, but just imagine the shock load that those gearboxes went through!

I was over when you were doing some maintenance, I recall the CIM wiggling around as it ran. A full sized CIM CAN run in the versa planetary, it’s not intended to, but it is possible. If you do plan to put that much weight on the little planetary gears it is important to support the weight, and to make sure they are mounted as securely as possible. When I saw the gearbox assembly there was about 1/16 of play between motor and versa planetary :ahh: . You really need those 5 pounds hanging off the end of the gearbox installed as snug as possible.

I don’t mean to scold you in any way, but you guys were kind of asking for it. Something had to give, those little pins took the blunt of it.

For future reference, here is the versa planetary loading guide, note how the mini cim and cim are absent from tables, just means you have to be extra careful.

“The VersaPlanetary gearbox may fail in one of two different modes: (1) output shaft yield stress failure or (2) 10:1
carrier plate ultimate stress failure.” ULTIMATE STRESS FAILURE D:>

Take this as a lesson, at least it wasn’t on a competition bot. Good luck this season :smiley:

Thank you for your concerns, I do realize that we were using it out of the scope of the versaplanetary designs but I was wondering if this had happening with any other teams using it for its designed use.(and to some teams who modified the versaplanetary to accommodate a minicim) Even so they performed wonderfully! (<3 Vex)


P.S. We have modified the gearbox a little more to accommodate the proper screws (10-32) to be mounted to the mini-cim and in which (I found out) some of the keys were a tad too long which actually cause the wiggling issue. They now experience no wiggling (and hopefully that will solve any issues).


I have pushed some 10:1’s to this point before, large shock loads make this start happening. The pins on the 10:1 are so close to the spline that this is the failure mode/the plate may also crack.

Obviously the CIM and Mini-CIM are use at your own risk, otherwise the loading guide is your friend.