Can CIM's compete anymore?

Nope, they are obsolete. Please send your old useless CIM motors to my PO box so I can properly dispose of them.


We used cims in 2018 and 2019 and are now switching to the Falcons as we want to upgrade to the latest and greatest. Neos are still a very viable option for teams.

And for the majority of teams that only use 2 CIMs per side on their drivetrain? How will they compare?

There’s more than one way to be good. We ran 6 mini CIM single speed gearboxes in 2019 and it’d be hard to argue that NEOs would have made a positive difference in robot performance. Identify what resources you have and focus on maximizing return on investments.

Edit to add direct answer: Yes, CIM’s can compete just fine.


These graphs were generated using a Release Candidate of 2020 changes to my drivetrain simulator and are representative of a cycling game like 2019.

TL;DR: The KOP drive train is more suited to every game than anyone gives it credit for. Kudos to AndyMark for consistently nailing it!

4-CIM 2019 KOP drive train @12.4V (10.71:1 ratio with default “long” configuration) with no current limit (theoretical 13.0ft/s @ 12V):

4-NEO configuration geared for 13.0ft/s @ 12V (theoretical), with a 56A current limit and blue nitrile 4" wheels:

4-Falcon500 configuration geared for 13.1ft/s @ 12V (theoretical), with a 58A current limit* and blue nitrile 4" wheels:

*NOTE - CTRE’s current limiting algorithm is not quite the same as REV’s, so the throttle responses may differ slightly.


For reference, according to the usage reporting from FIRST, 18.6% of teams had a SPARK MAX object in their code, which is probably a solid proxy for how many teams actually used NEOs on their robot last year.


Even if you can’t afford a fully decked out Falcon robot, you can for sure use them smartly in 1 or 2 places and get 95% of the robot performance compared to someone who has a fully decked out BLDC robot.


This year, sure. The Falcon hardware seems great. But, how does the software work? That always seems to be the lagging component of new motor controller hardware. And, will they be available? In the last few years, we’ve definitely seen issues with vendors not having enough stock of new components to supply demand. There’s a lot of risk there.

Our first use of Falcons will likely be in an off-season robot build. If they work there, then we’ll probably buy a supply to have on hand at the beginning of the following season.


You could have used neos…

Care to elaborate on this point?


Has CTRE ever left anyone wanting or released an incomplete product?

I took a few years off FRC but can’t think of an example where they weren’t my preferred vendor.

The big software change two years ago comes to mind.


On paper performance the falcons have alot more going for them than the Neos. And seems vastly superior.

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Do they, though? You’re not sustaining, and probably not even hitting, peak power. The efficiency gains exist, but aren’t nearly as big.


But then we would have had to completely ditch the last three years of programming experience our team has spent working with Talon SRXs and everything they can do. That’s the reason we (and a lot of other teams) didn’t jump ship to using Neos, because we didn’t want to have to also go to using SparkMaxes. It was too steep a hill to climb for us.


We used CIMs very effectively during an offseason event this year…

… as ballast in our defense-only NEO swervedrive bot. 70 lbs of CIMs were loaded in our Pushing Power™ cube bolted to the frame of the robot. Quite effective.

In all seriousness, CIMs are definitely still going to be a valuable motor for a lot of teams. We are not planning to use them any time soon (but will will be hanging on to our miniCIMs for the time being). But they are definitely an affordable durable fool-proof motor option that I believe will still be a competitive solution for many teams for a long time to come.


The graphs above show a nominal gain in time / throttle response, and a nominal (at best) gain in power efficiency for a standard short sprint. Even when geared for the same exact speed for a 2/3 field sprint the Falcon only comes out ahead by less than a robot length across the entire length of the sprint. Why isn’t stupidly, astoundingly faster? The Falcon is current-limited for nearly a full second on a 40-foot sprint.

There are some major advantages that the Falcon has over the NEO for a drive train, but power/efficiency just isn’t one of them when it comes to the constraints on FRC (even when using NEO data provided by VEX).

The efficiency helps when it comes to single-motor mechanisms. Yet when scaling to multi-motor mechanisms (for power density) even the CIMs can come out ahead on everything but weight depending on the mechanism constraints and cost. For understanding who to trust when it comes to which considerations matter, you really have to understand who is financially connected to IFI/VEX, REV, and who is not financially connected at all. The Falcon release thread is like night and day in that respect :roll_eyes:.


Yes, CIMs can still compete. For >80% of teams, CIMs are still a great drivetrain workhorse.

Can I heart a post twice?

They do beat the NEO on power/efficiency specs within the FRC design space, but by narrow margins that don’t matter much. Very well done engineering to achieve that, and I don’t mind them trumpeting it in their marketing.

(My excitement for the product comes from having NEO-level performance come from a single integrated package implemented on the CTRE programming framework.)


For what it’s worth, we did last year with a programming team of two and it really only took them a week or two to figure out the NEO and SparkMax. You definitely could have put NEOs on your drivetrain, and it would probably have been less painful than you think. Lots of teams made the switch halfway through the 2019 season and went through the same learning curve. Not a cake-walk, but not impossible.

The ~780W peak power is a crazy number, but it’s not practically attainable. (I assume that’s what you’re talking about with the on-paper performance comment.) Current draw at that point is 120A. The practical differences between the Falcon and the NEO (as I see it) are:

  1. A nominal improvement in efficiency. This means a little more power output for each watt put into it. They’re pretty close though.
  2. Built-in controller. This means fewer points of failure, but the failures you do have will be more expensive.
  3. Higher free speed.
  4. Cooling port, for those who will use it. (Can the Talon FX read the motor temperature? It would be cool to have a solenoid that can trigger to automatically cool your motor.)
  5. Spline shaft. Incredible feature or expensive gimmick? Time will tell.

Arguably the more interesting feature is a user replaceable shaft… I would love to see multiple options here.