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Drivetrain Speed Calculator

How fast will this drive actually go? Pick your cartridge, gearing and wheels to get a top speed in ft/s.

Inputs

This changes the answer. Wheels mounted at 45° drive the robot forwards faster than they turn, because both sides push along the diagonal.

The color of the plastic insert in your V5 motor.

Set both gears the same for a direct 1:1 drive.

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

Top speed

—ft/s

Top speed in inches per second

—in/s

Top speed in miles per hour

—mph

Wheel speed

—RPM

Speed at the wheel rim

—ft/s

Before the drivetrain geometry is applied.

What the layout does to it

—

Forward speed ÷ rim speed.

Sideways speed

—ft/s

Zero for tank, which cannot strafe at all.

Pushing force, against tank

—

Speed and force trade one for one.

Gear ratio

—

Driven : driving.

Time to cross the field

—sec

144 inches, at top speed, ignoring acceleration.

How this is calculated

Three steps, no hidden factors.

wheel RPM = cartridge RPM × (driving teeth ÷ driven teeth) inches/min = wheel RPM × π × wheel diameter ft/s = inches per minute ÷ 720

The 720 is just unit bookkeeping: 12 inches per foot × 60 seconds per minute.

Watch which way the gears divide. Putting the small gear on the motor and the large gear on the wheel makes the robot slower and stronger. Teams get this backwards often enough that it's worth checking twice: the result is a drive that looks quick on blocks and gets shoved around in a match.

What counts as fast

There's no single right answer here. A drive built to push wants torque, and a drive built to collect and score wants speed. What matters is that you picked your figure deliberately and can say why.

Sources & assumptions

Cartridge speeds (100, 200 and 600 RPM) and wheel diameters are VEX published figures. Wheel circumference is computed as π × diameter rather than from VEX's advertised "travel" numbers, which are rounded to the nearest 10 mm.

Assumes a single external gear pair and no wheel slip. Chain drives behave the same way for speed, so use sprocket tooth counts in place of gear teeth.

Save this run, and compare

Keeps what is on screen so you can change something and see both sides of the change. Saved in this browser only, never uploaded.

Save this as evidence

Collects what you entered, what came out, how it was worked out, and anything the tool flagged, with a timestamp and a version so someone else can reproduce it.

This is evidence, not a notebook entry. It deliberately does not write your problem statement, your reasoning, or your conclusion, because under RECF rules an Engineering Notebook has to be the students' own work and no tool may generate or organise its content. Take the numbers, decide what matters, and write it yourself.