CIM vs mini CIM

What are the differences between normal sized CIMS and mini CIMS

Mini CIM:


Length of the motor, ~100W.


was just about to post it…but this Post

the mini cim is smaller


Moved to Competition - Rules/Strategy

I remember someone from Vex doing a detailed analysis of this one or two years ago, specifically for drivetrains I believe. But as people said, the CIM is heavier and slightly stronger.

A mini-CIM is roughly 2/3rds as powerful as a CIM.

They can be used interchangeably - you can swap a CIM for a mini-CIM even in a gearbox that has other CIMs or mini-CIMs in it, and it will work, just with reduced or increased power.

The mini-CIM also has internal ball bearings supporting the output shaft, while the CIM has bushings. This results in slightly higher efficiency.

Measured performance data from VexPro has indicated that the miniCIM sees less of a performance drop than the CIM over time when seeing extended use under load. This is what started the trend of teams using 6 miniCIM gearboxes as replacements for 4 CIM gearboxes. Performance seems to be improved.

As a very general rule of thumb, if you can’t decide what to use, I would use a mini-CIM. This gives you the option to switch to the full CIM if you later determine you need greater output power. But this is, of course, highly dependent on gearing and application.

Neither motor will make or break your season - they are both highly robust and reliable motors.


Seems like a bizarre place to move it. This is a technical thread, is it not?


I moved it to Technical / Motors just now; I think Gary was assuming it was a rules question rather than a question about how the motors work.

Good choice. I just knew it didn’t belong where it started.