Drivetrain Type Comparator
Take one set of motors, gears and wheels, and see what each drivetrain layout would do with them. Same parts, four very different robots.
Inputs
Diameter across the wheel. Mecanum and flex wheels share a diameter with the plain ones, so pick by name rather than by size. Anything not listed can be typed in.
Results
| Layout | Forward | Strafe | Push vs tank | Motors | Wheels |
|---|
How this is calculated
Every layout here is handed identical motors, gears and wheels. The differences are entirely in how the wheels are pointed.
Tank
Wheels aligned with the robot. Everything the motors produce points forward, so it is the baseline for both speed and force, and the only layout that can use traction wheels everywhere. It cannot move sideways at all. To go left you turn, drive, and turn back.
X-drive
Four omni wheels at 45°. Because no wheel points where the robot is going, each only needs to roll at cos 45° of the robot's speed, so it travels √2 faster than tank, forwards and sideways alike. The same cos 45° works against you for force, giving about 71%.
Note that the √2 is not unique to the layout: gear a tank drive up by √2 and you get the same trade. What an X-drive actually buys is strafing.
Mecanum
Wheels stay aligned with the robot, and angled rollers on each wheel let it slide sideways when the four are driven in opposing pairs. Forward speed and strafe speed both come out at wheel speed, so unlike the X-drive there is no speed bonus and no speed penalty. You gain sideways motion and nothing else changes.
The cost is grip and complexity. Mecanum wheels are expensive, heavy, and hold poorly, and strafing scrubs the rollers hard enough that it is noticeably less efficient than the geometry suggests.
H-drive
A normal tank drive with one extra wheel mounted sideways in the middle. Forward performance is untouched, with full tank speed, full tank force and traction wheels allowed, and strafing is bolted on.
The catch is that strafing has one motor doing the work while dragging the tank wheels sideways across the tiles. It is slow and weak, and it costs a motor from a budget that is already capped. Good when you need occasional alignment rather than genuine sideways mobility.
Choosing
There is no ranking here because the answer depends on the game. If matches are decided by contact, tank's grip advantage is hard to argue with. If they are decided by getting into position quickly and precisely, the ability to strafe can matter more than any of the numbers above.
What this table is good for is checking that you know what you are giving up, and for noticing when a layout is chosen because it looks impressive rather than because it wins.
Sources & assumptions
Cartridge speeds and wheel diameters are VEX published figures. The cos 45° and √2 factors for the X-drive are exact geometry. Mecanum forward and strafe speeds follow from standard mecanum kinematics, in which the four wheel contributions sum to wheel speed in both directions.
Roller friction, scrub losses and the grip differences between wheel types are not quantified, because no VEX figures exist for them. They all work against the non-tank layouts, so treat every push figure other than tank's as an optimistic ceiling.
- VEX Robotics — V5 Smart Motor & Gear Cartridges (276-4840) — checked 2026-08-17
- VEX Library — Understanding VEX V5 Wheels — checked 2026-08-17
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