Advice on gearboxes for a rookie team

Hello. As a rookie team preparing for the season, what gearboxes do you recommend purchasing, ideally from andymark. Our motors are NEOs and Redlines. So far what I think we need is CIM sports, maybe a toughbox mini, and sport gearboxes for the redline motors. In addition to advice on the type of gearboxes, what ratios do you recommend for having on hand?

I would highly recommend looking into stuff on WCP, high quality gearboxes for CIM’s and NEO’s. Although I would say running NEO’s on your gearbox is a great idea if you dont use CIM’s. Gearboxes – WestCoast Products


Last season we used a custom version of their flipped SS single speed 2 stage gearbox with NEO’s. It works incredibly well for drivetrains.

But if your looking for stuff like planetary gearboxes which can be used for elevators, climbers, etc, I would suggest looking into getting REV MAXplanatary’s. They are easy to setup and don’t require any pre-greasing.
https://www.revrobotics.com/frc/maxplanetary-system/
download.jpeg-3

I would need to do some more research on andymark though sorry.

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If I was spending my own money for a team with no stockpile, I’d buy:

  • REV MAXPlanetary for the easier assembly and configuration (especially on NEO as you aren’t pressing a pinion onto them), but the AndyMark Sports are still really good for RedLines. When we were on RedLines for stuff, we liked to stock 20:1 and maybe 1-2 100:1; that’s about 1000 and 200 RPM output speed with a RedLine. That’s in the ballpark for most mechanisms.
  • I would not buy a TB Mini yet. Historically, two come as part of the drive base kit and they’re a really drivetrain-focused gearbox. But they’re still good gearboxes, pretty much bulletproof if assembled right. We won Electric City on them, then took the guts and put them into the Thrifty Bot 3-motor plates designed for them. Zero trouble through Championship, SCRAP, and lots of drive practice.
  • If possible, I’d look at the REV UltraPlanetary and NEO 550 combo for your high-speed mechanisms (up to about 30:1 reduction). It is an incredibly light, compact, and cheap solution for conveyors and intakes while still getting all the smarts of a SPARK MAX (namely, current limiting). But again, a 57 Sport is still a completely valid and robust solution.
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Brief response; hopefully this helps. These are my opinions based on my own experiences with teams I’ve coached and been in playoffs/elimination rounds with.

  • Use the KOP chassis. I’m assuming that in these comments. Great starting point for rookie teams, and the Everybot always uses it (plan to thoroughly review and potentially use the Everybot design; usually published mid- to late-January).
  • 100% agree with the comment to use WCP branded gearboxes from West Coast Products. Rock solid. Many configuration options.
  • Sorry, but CIM sports and toughbox mini are not up to the loads that NEOs are capable of. Have seen too many of them break, including in Elim rounds… 100% agree with the advice to use Rev Robotics MaxPlanetary for all gearbox needs, especially for lift systems.
  • I’d say sport gearboxes are OK for light to medium loads, but not for lift mechanisms. Again, my favorite for that is MaxPlanetary.
  • For a rookie team I recommend good mid-range ratios for drivetrain motors. Say 6:1 (that’s a 12-tooth pinion and 72-tooth driven gear). That will be a little quick for 6" wheels, and feel a little slow for 4" wheels. Everyone thinks they want more speed, until they actually drive the robot in matches without enough practice. Mid-range speeds will give you more control and repeatability – and reasonable pushing power – unless you get LOTS of time for practice before your events and can therefore actually use more speed (which very few rookie teams actually accomplish).
  • For manipulator gearboxes, the advantage of systems like MaxPlanetary is you can buy a variety of gear ratio stages and have a wide range of options available to you. A NEO and a 12:1 MaxPlanetary gearbox has enough torque and durability to lift your robot (I’ve seen sport gearboxes break on lift systems). We use other ratios mainly for the purpose of getting the right mechanism speeds; with this combo, adequate torque is rarely the problem. (Having cited the advantages of MaxPlanetary, I recognize they are hard to get right now. But I think we’ll see them become available at various times over the next 2 months.)

Good luck!

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I would recommend a single speed gearbox that you can adjust between 12 and 16 ft/s by changing the pinion on the motor (slower speeds for shorter sprint distances, higher speeds if we need to go across the whole field). With brushless motors I don’t recommend shifting - it adds failure points, cost, and complication that is not useful for most teams. TBH the kit gearbox is pretty good, although it’s a bit hard to swap stuff on it. As a rookie, focus on the other parts of the game.

Alternatively, (this is definitely bad advice)

I may be ex-AndyMark, and I already said my part about the MAXPlanetary, but this? Baloney.

That banner I mentioned was hung off of ferocious defense with four NEOs fed into a Toughbox Mini, and the gearboxes never let us down. Same gears and shafts ran perfectly well through Championship with six NEOs and even harder defense with an even heavier robot on fresh wheels. The design of the Toughbox Mini is not the problem.

I will grant that you can’t stall a NEO on an 80:1 or 100:1 CIM Sport with no limiting, but AndyMark says as much on their product page. And honestly, how many mechanisms on a modern FRC robot need that kind of torque? Our 2020 climbers were at 80:1 on a RedLine, and were more than plenty to drive a robot skyward.

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This is not true. Unless you’re allowing your motors to stall without any reasonable current limiting (don’t do this), those gearboxes are SOLID. They have been our go-to gearboxes for our highest torque applications.

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We really like the EVO Slim gearboxes from AndyMark. They’re drop in replacements for the toughboxes on the kit chassis. The toughboxes are also good, no issues there. We like the EVOs because they’re easier to assemble and keep together off of the robot

I’ve heard really good things about the TTB 3 motor kit which bolts right on to the kop chassis and uses the gears from the toughbox. Great choice if you want to upgrade to 3 motors.

The Sport gearboxes are near bulletproof, the drawback being the inability to customize the gear ratio with different stages. We loved the MAXPlanetaries this season, and plan to use them again for any high load mechanisms in the future.

REV UltraPlanetaries are also an option for lower load mechanisms like intakes if you’re using NEO 550s.

I know people are touting the WCProducts gearboxes- they are good gearboxes, but do not integrate very easily into the KOP chassis, if that’s what you’re using.

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I will also endorse the MaxPlanetaries. We used them for all gearboxes on our climb and intake and I couldn’t be happier. Easy to use and basically indestructible. UltraPlanetaries are really great for highspeed low load applications, but avoid overtightening the assembly screws and minimize radial loading on the output shaft. Versa Planetaries are decent, but the stages are not contained, and they use a combination of 8-32 and 10-32s, so make sure you assemble very carefully. The sports seem well made but they are customizable like the others which defeats the point for my team.

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Good observations. And to be clear, I am a fan of AM and we use a lot of their parts. But not the parts I mentioned for the purposes described. I agree the specs would indicate these parts will work well for the applications cited. But please accept my anecdotal evidence: we’ve seen 3 of these units fail on partner robots during playoff runs in the last 3 seasons, once in the finals, and twice in semifinals, all at different events. I cannot attest to the quality of assembly because these failures were on other robots (not ours) – but these robots appeared to be designed and built well by experienced teams. And this may be less than a 1% failure rate across all the parts in use across FRC, but this is a very-high incidence rate in our direct set of experiences. I’m very happy to hear that your experiences are much better, but what I shared does represent the preferences and choices we use now for our robot designs.

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That is excellent to hear. As I commented to @Billfred, we have seen some problems on other robots and believe there are better options (that we haven’t seen problems with) for high-torque applications. I am a fan of AM and we use a lot of their parts. But I’ve seen breaks too often to be 100% confident that less-experienced teams will remember to do things like current limiting to prevent potential mechanical issues like this. Again, I recognize my observations represent a very small sample set that may be less than 5% of the full FRC experience set, but it is the sample set we make our decisions on. Thus it can only be represented as opinion

Everything in the ToughBox line is a good (great, really, considering the price!) product, provided you follow the instructions and perform a “burn-in” cycle before use.

I cannot overstate the importance of following that instruction; the ToughBoxes are great but they’re not toleranced very tightly and can/will bind if you skip it. If you perform the step, though, they’re among the most reliable gearboxes I’ve used.

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Maybe I’m missing something here, but are the EVO’s (and other similar “open” gearboxes) meant to run with no grease? What’s the lifespan of those gears?

Nope, you’re meant to add grease. You do have to be conservative with how much grease you use, and using a sticky grease (such as red’n’tacky) helps to keep the grease on the gears. Regreasing the gears is part of our periodic maintenance routine. We typically use some sort of cover (3d printed/polycarb/gaff tape) to keep the surrounding area clean, but that’s by no means necessary. The gears on the EVO series of gearboxes are steel- we’ve never had any failures.

Ok, that makes more sense. I just pictured what the inside of a CIMple box looks like after a while and didn’t recall seeing any “snail trails” left by robots with open gearboxes.

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