FRC Drivetrain Types: Tank, Swerve, and Mecanum

The drivetrain is the foundation of your robot - it decides how fast you move, how you maneuver around defenders, and how hard the rest of the build will be. If you are weighing tank vs swerve drive (or wondering where mecanum fits in), here is an honest, beginner-friendly breakdown of the three drivetrains you will see most in FIRST Robotics Competition.

Tank (Differential) Drive

Tank drive, more formally called differential drive, is the classic FRC drivetrain and the easiest to build and program. You have wheels on the left side and wheels on the right side, and each side is driven together. The robot moves by sending different amounts of power to each side - drive both sides forward to go straight, and spin the sides in opposite directions to turn in place.

The tradeoff is simple: a tank drive cannot move sideways. To reach a spot to its left, it has to turn and then drive. In exchange you get a drivetrain that is cheap, rugged, easy to repair, and hard to get wrong - which is exactly why it is the standard recommendation for rookie teams.

In code, WPILib handles this with the 'DifferentialDrive' class, which gives you a few control styles:

• Tank drive: one joystick axis controls each side independently.
• Arcade drive: one input for forward/back speed, another for turning rate.
• Curvature drive: turning controls the radius of the turn, more like the steering wheel of a car.

If you are building your first robot, start here. Our Mechanical & Build guides walk through laying out a solid differential chassis step by step.

Mecanum Drive

Mecanum drive trades some of that simplicity for the ability to move in any direction. The trick is the wheels: each mecanum wheel has free-spinning rollers mounted at a 45-degree angle around its rim. Because the rollers (not the wheel itself) contact the floor, each wheel pushes at an angle instead of straight ahead.

Mecanum wheels come in pairs - two with rollers angled one way, two the other - and are mounted so that diagonally opposite wheels match (front-left matches back-right, front-right matches back-left). By driving the four wheels in the right combination, the angled forces add up or cancel out, letting the robot strafe sideways, drive diagonally, and rotate. That makes it a holonomic drivetrain: it can translate while rotating.

A couple of honest caveats. Because of friction in those rollers, a mecanum robot drives a little faster straight forward and back than it does sideways, and it tends to have less pushing power and traction than a comparable tank drive - a real disadvantage if a match involves shoving. WPILib supports it through the 'MecanumDrive' class, with cartesian and polar control and an optional gyro input for field-oriented driving.

Swerve Drive

Swerve is the most capable drivetrain in FRC and now the most popular among competitive teams. Instead of fixed wheels, swerve uses an independent module at each corner of the robot. Every module has two motors: one to spin the wheel and one to steer it to any angle, plus an encoder so the code always knows which way the wheel is pointing.

Because each wheel can point anywhere, swerve can do something neither tank nor mecanum can do cleanly: translate in any direction while rotating to face wherever you want, all at full traction. That control is a huge advantage for dodging defense and lining up to score.

The cost is real complexity. Swerve needs roughly twice the drive motors of a tank drive (a typical four-module setup uses eight motors), it is heavier and more expensive, and it demands more maintenance and far more careful programming. WPILib treats swerve through its kinematics system rather than a single simple drive class - you describe the robot's desired motion as a 'ChassisSpeeds' object (forward, sideways, and rotational speed), and swerve kinematics converts that into a target speed and angle for each module.

Most teams do not machine their own modules. Commercial off-the-shelf options like Swerve Drive Specialties MK4, REV MAXSwerve, and WCP Swerve X are widely used and well documented, which has made swerve far more approachable than it was a few years ago.

So Which Should You Pick?

There is no single right answer - it depends on your team's experience, budget, and time:

• New team, limited resources, or tight build timeline: tank drive. Reliable, affordable, and forgiving.
• Want omnidirectional movement without the full swerve commitment: mecanum, accepting the traction and pushing tradeoffs.
• Experienced team with the budget, programming depth, and time to maintain it: swerve, for best-in-class maneuverability.

Whatever you choose, get the fundamentals right - frame geometry, gear ratios, and wiring matter more than the drivetrain badge. Dig into the full Mechanical & Build department on LearnFRC to plan and build your chassis the right way.