Swerve Drive Modules

I am looking into getting my team a swerve drive for next season. I wanted to ask everyone’s opinion on the various modules out on the market. I have read the forum on the advantages and disadvantages on using falcon and neo motors, but I wanted some insight on the advantages and disadvantages on the different brands of swerve modules. Any bit information will be helpful and much appreciated. Thank you in advance.


We’ve had SDS MK3s and now MK4s with Neos and are quite happy with them. We decided a while ago the Falcon’s were too expensive with integrated controllers and went with the Neo line instead. Given the history of issues with them, we’re also quite happy with that choice.

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We had neos on the SDS Mk3 (1 yr) and falcons on our Mk4i (2 yrs), they have been great for us so far and would recommend them. I would however recommend making a jig to cut tread or something of the like.


We’re extremely happy with SDS MK4i’s, but I’ve heard the West Coast Products SwerveX is just as bulletproof. The Rev swerve paired with aluminum wheels is also a good option with supported code base that is likely more affordable if you’re starting out.

I’d still vote for SDS or WCP though simply due to being able to run larger wheels.

We stuck to Falcons this year, reusing as many of our V1 and V2’s as possible. FWIW we’ve never had a single Falcon failure since we started using them in 2020 after pre-use procedures. That part is really up to you.


We just purchased some of Rev’s for the following reasons…
-You do not need two full-size motors per module
-They are in stock
-We already have the compatible motors

There are many other considerations of course, and we are not in love with the 3 inch wheels, but we have never used swerve, so thought this would be a good entry point.


Rev Maxswerve modules are also smaller and lighter than the other swerve modules.
Your wheelbase for frame perimiter is also larger.


IMO, there are three main competing COTS swerves right now:
Swerve Drive Specialties - Mark4i / Mark 4
West Coast Products - Swerve X (different mounting options)
REV - MAXSwerve
There are others or you can custom make one, but those three are the big players.
At our competitions so far, swerve teams mostly used SDS Mark4i and REV.

The REV MAXSwerve is new this year. It uses a NEO550 for the turning motor but can use a Falcon or NEO for the drive motor. The others can use Falcons or NEOs for both drive and turning motors.

The REV MAXSwerve uses a 3" wheel that is standard as an overmolded rubber+plastic wheel, with an option to use an aluminum wheel to which you apply tread.
The other two use a 4" alumimum wheel with tread as standard.
Ground clearance for the REV is higher than the “flipped” (Mark4i) versions of the other swerves but lower than the “standard” (Mark4) versions.
Motors on the “standard” versions protrude pretty high above bumpers and are vulnerable to damage. The “flipped” versions put the motors underneath structure for better protection. REV is kinda in the middle, the motors are exposed but the modules are smaller and lower profile so there’s less risk of damage.

The REV swerves are cheapest - $300 a corner, including encoders, plus the cost of the motors & controllers. But if you want an aluminum wheel (which I recommend) it’s an extra $30 each. You also get 3 different gear ratios for your $300.

The Mark4i is $365 plus encoder (another $40-60), the SwerveX is $305-340 plus encoder. Motors (and controllers if you use NEOs) are extra on all swerves.

We are running MAXSwerves with NEOs as the drive motor this year and love them - they are reliable, not too hard to assemble and easy to deal with. They do have issues with the rubber coming off the plastic wheel, and though REV promises that an upgraded wheel is coming I would recommend using the aluminum wheel option. For our competitions so far we have kept a set of spare plastic wheels ready with gears preinstalled, so that “changing tires” is an easy thing to do in the pits. Next year we’ll use aluminum wheels with tread.

This is our first year with swerve. Programming wasn’t too difficult with the MAXSwerve since REV provided good libraries and examples.
Make sure you get a gyro too, we have been loving field oriented driving.

I would say that starting out, the REV swerves are a good choice because of the support you get from REV, just be careful of the wheel issues.

My $0.02


We’ve used WCP Swerve X modules for the last two seasons and have been extremely happy with them. Last season it was the standard tube-mount units, this season it is the inverted corner-mount units. Both are very robust and have stood up to some hard use without a hitch. We even slammed the forward units on last season’s robot into the high bar a number of times while climbing during our first event and they were fine (though we did break one of the Falcons that way.) They took two serious falls from the traverse bar, one directly onto the wheels, with no damage whatsoever. The geared option is ideal, since there are no belts to break or slip and they run very smoothly. All in all, a fine product and one we’ll keep using as long as it’s available.


Thanks to all of you all for your feedback. It has been very helpful.

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can the swerve x fit a neo instead of a falcon and or cim? i would think so?

Yes, entirely possible. Of course, you’ll have to get a bit more inventive to place the SparkMaxes (as with any other swerve module), but the motors themselves will be no problem.

This was our first year of swerve and couldn’t be happier with our mk4i modules on our practice and competition bots. There was an issue other teams had with the drive shaft which we did not. Once the issue was brought forward SDS designed a new shaft in days and sold them for just $1 to cover material costs. We had swapped to the longer bolts before the shaft was available and ran it that way the whole season without any issues. I did message Patrick at SDS about the bolt size for mounting the modules being 8 and if there was a problem with using REV max tube that has holes for 10 bolts. He had said he was thinking of changing the module mounting bolt to 10 since that was what he wanted to do initially but went with 8 to fit the holes on the VEX tube and now that more people are using max tube he might switch to 10 bolts. He said there wasn’t a problem using the existing 8 bolts with the 10 hole though

Edit: The only concern we had when going with the mk4i was the open-ish gears on top and something possibly falling into them. That was quickly solved when one of our students designed and printed these. They worked great and look sharp in my opinion. Extending down the sides was two fold a guard and a grease flinging shield which was not an actual issue like we originally thought it could be.


Another satisfied Mk4i customer here. No failures so far this year, great experience with the Mk4 modules last year as well, through some serious abuse. Love the low profile of them.

We have used SDS Mk4i modules in the past and for our current robot and we have been extremely satisfied with the modules. There weren’t any failures, and we ran it through multiple competitions as well. Our modules uses falcon motors, and we haven’t used neos on the modules yet, but from what i heard, neos also work great as well. Most teams have been making the switch to swerve this year from what i can tell.

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