Combining CIM and NEO in drivetrain?


Hi everyone,

I have a rookie question about drivetrain.

Our team was able to secure two Neos, and two Spark max motor controllers. Because Neos have built-in encoders, someone recommended that I use them in the drivetrain along with two CIM motors. I have also had people say that using brushed and brushless motors together is a bad idea. Does anyone have advice on this? I dont think our team has the money for two more neos and spark maxs.

Also, I have had someone say I should just sell the Neos and Spark maxs. Should I sell them or should I use them for another part of the robot (intake, shooter, etc.)? and if I did want to sell them, where would I?


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My team did this last season and had no issues so I think you’ll be fine


5172 ran that setup in their reveal and possibly throughout the rest of the season, so it’s definitely possible


Can confirm that the ran them through the rest of the season, shown here in their Behind the Bumpers. I’m no engineer, but would running both motors at full speed in a gearbox cause any problems, the NEO has a little bit higher free speed.

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The posts above seem to suggest minimal issue mixing and matching in the same gearbox, but should you decide to use just cims and still want encoders, you probably have two good options for use with Talon SRXs.

If you’re using a toughbox gearbox from the last 2 years or so, they already have a magnet protruding from the back of the output shaft to attach an SRX Magnetic Encoder, or you could attach a CIMCoder 256 to the CIM’s shaft. Each can plug directly into a Talon SRX’s data port and provided you account for gear ratios with the CIMCoder, can be used with ease.

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I can confirm that they ran it for the entire season, since I got to inspect them at MSHSL state championships.

They did it so they could use the built in PID control on the Talon SRX connected to the CIM and an external encoder, and then use the NEO for some extra power (with the SparkMax set to follow the SRX).


Running the Neo and CIM in the same gearbox will put more load on the Neo when speed is high, and more on the CIM when speed is low. This is actually not a bad situation for an FRC drive train, because most drivers like to go flat out whenever feasible. The CIM helps boost acceleration.

5172’s record is 2019 is pretty impressive, including 2 Regional wins. I got to see them up close in the Carson finals – they were scary quick.


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