Every paddock speaks two languages. There’s the one drivers use over a chassis, and the one the data screen speaks back.
This karting glossary covers the second one. 75 terms, grouped by topic, each defined in plain words so a driver, a parent or a mechanic reads the same meaning.
I started karting at six, and the jargon arrived faster than the lap times did. The vocabulary kept growing through the 2013 world championship and all the way into F3, GP3 and F2. But almost every word in those briefings was already alive in karting.
Use the page two ways. Skim the section you’re working in, or ctrl+F straight to the term that confused you.
Core channels
A channel is the atom of telemetry. Everything else on this page is built from these.
Telemetry. The recording of what the kart and driver did on track, sampled many times per second and downloaded for review. The wider engineering sense covers any measurement taken at a distance.
Data logger. The onboard unit that records every channel during a session and then hands the laps to your analysis software; the hardware options are compared in kart data loggers explained.
Channel. One stream of recorded data, such as speed or RPM. Each sensor feeds at least one channel.
Sampling rate. How many readings a channel records per second, measured in hertz, so a 10 Hz channel writes ten values into its file every single second.
GPS speed. Kart speed calculated from satellite positioning instead of a wheel sensor. The standard speed source on modern karting loggers.
RPM. Engine revolutions per minute, usually read from the spark plug lead. The oldest karting channel and still one of the most useful, as the kart RPM data guide shows.
Water temperature. Coolant temperature in a liquid-cooled engine, the channel that tells you whether the engine sits in its working range or is quietly being cooked.
EGT. Exhaust gas temperature, taken by a probe in the exhaust header and used by drivers and mechanics to judge carburation, the craft covered in the kart EGT guide.
CHT. Cylinder head temperature. The air-cooled engine’s stand-in for water temperature.
Lambda. The air-fuel ratio measured by an oxygen sensor in the exhaust. A direct read on rich or lean running, explained in the lambda sensor guide.
Throttle position. How far the throttle is open, expressed as a percentage. It needs its own sensor on the pedal or carburettor.
Brake pressure. Hydraulic pressure in the brake line. It shows how hard you brake and how you release, not just where you started.
Steering angle. Rotation of the steering wheel, logged by a dedicated sensor, and the channel that reveals the small corrections you never felt yourself make.
Traces, graphs and math channels
Speed trace. The graph of speed against distance for a single lap, the first chart every data session opens with and the backbone of every comparison that follows.
Delta time. The running time gap between two laps at every point on the track, the one line that shows where time is won and lost, unpacked in delta time explained.
Overlay. Two or more laps drawn on the same chart for direct comparison. The working method lives in the overlay analysis guide.
Reference lap. The lap everything else gets compared against. Usually your best, sometimes a teammate’s.
Ghost lap. A reference lap replayed alongside your own driving, like the ghost car in a racing game.
Track map. The plotted shape of the circuit, built from GPS or from speed and lateral G, which ties every data point to a physical place on track.
Math channel. A new channel calculated from existing ones rather than measured directly. The recipes are in math channels for karting.
Smoothing. A filter that averages out jitter in a channel so the underlying shape is readable. Too much of it hides real detail.
Sampling noise. Random wobble in a channel caused by the sensor or electrical interference. The kart didn’t do it; the electronics did.
GPS drift. Position error that creeps into satellite data and bends the track map or the speed trace.
Video sync. Lining up onboard video with the logged data so every frame matches its exact point in the traces and your eyes can confirm what the numbers claim.
Lap and time analysis
Theoretical best. Your fastest sectors from one session stitched together into a single imaginary lap, which makes it the lap you have already proved possible, just in pieces.
Sector. A timed segment of the lap, usually three or four per circuit. Working sector by sector is its own discipline, covered in sector analysis for karting.
Microsector. A much smaller timed segment, often a single corner or less, giving finer resolution for finding exactly where the time hides.
Split time. The elapsed time at a fixed point on the lap, shown the moment you cross it.
Lap consistency. How tightly your lap times group across a run; why that beats one hero lap is the argument of the lap consistency article.
Consistency spread. The gap between your best and worst representative laps in a stint. Smaller is better.
Purple lap, purple sector. The fastest lap or sector of the entire session, coloured purple on most timing screens. Yes, that’s where the name Purpl comes from.
In-lap. The lap that ends in the pits. Usually slow, and excluded from analysis.
Out-lap. The lap that starts from the pits, spent bringing tyres and engine up to temperature.
Flying lap. A complete lap started at full speed. The only kind worth comparing.
Driving metrics
These are the numbers that describe the driver rather than the kart. They sting more, and they teach more.
Lateral G. Sideways acceleration in cornering, expressed in multiples of gravity, and the measure of how hard the tyres are working across the kart.
Longitudinal G. Acceleration and braking force along the kart’s direction of travel.
Combined G. Lateral and longitudinal G combined into one total grip demand.
Friction circle. The plot of lateral against longitudinal G, showing how much of the tyre’s total grip you actually use; read it properly with the friction circle guide.
Minimum speed. The slowest point of a corner. One of the most telling numbers in kart data.
Apex speed. Speed at the apex of the corner. Often the same as minimum speed, but not always.
Corner exit speed. Speed at the point where the kart runs straight again, where small gains compound all the way down the following straight.
Braking point. Where braking begins, read from brake pressure or the speed trace.
Brake release. The way brake pressure comes off as the corner arrives. Its shape separates smooth entries from snappy ones.
Trail braking. Carrying reducing brake pressure past turn-in instead of finishing all braking in a straight line.
Coasting. Time spent on neither throttle nor brake. A little is deliberate; most of it is wasted lap time.
U-shape vs V-shape corner. Two ways through the same corner: a wide arc that protects rolling speed, or a deep brake, sharp rotation and early throttle. The traces show which one a corner rewards.
Racing line. The path through a corner that produces the best lap time. Not always the geometric ideal.
Engine and gearing
Limiter. The maximum RPM the ignition allows the engine to reach; hitting it long before the braking point means the gearing is too short.
Limiter metres. The distance travelled sitting on the limiter before braking. A gearing diagnostic you read straight off the RPM trace.
Gear ratio. The relationship between engine speed and axle speed, set by the two sprockets. How to choose it is the subject of the kart gear ratio guide.
Sprocket. The toothed wheel the chain runs on. Swapping rear sprocket teeth is karting’s main gearing change.
Minimum RPM floor. The lowest RPM the engine falls to in the slowest corner, watched because dropping below the engine’s happy range kills the drive away from it.
Short shift. In gearbox classes, changing up before peak RPM to settle the kart or protect the engine.
Tyres and track condition
Cold pressure. Tyre pressure set before the run with the tyre at ambient temperature, the starting point of the whole method in the kart tire pressure guide.
Hot pressure. Pressure measured the moment you come in, while the heat is still in the tyre.
Pressure delta. The difference between hot and cold pressure. A direct read on how much heat the tyre built during the run.
Tyre temperature. Surface or carcass temperature of the tyre, measured by probe or infrared sensor.
Temperature window. The range in which a tyre grips best. Below it the tyre slides; above it the tyre overheats and fades.
Heat cycle. One full warm-up and cool-down of a tyre. Every cycle changes the compound a little.
Grip evolution. The change in track grip across a day as rubber, temperature and traffic shift, rewriting your numbers from one session to the next.
Rubbering in. The laying down of tyre rubber on the racing line, raising grip lap after lap.
Green track. A surface with little rubber on it: after rain, overnight, or at a freshly cleaned circuit. Low grip, for now.
Timing hardware and session terms
This is the language of timing screens and debrief rooms, from club practice to FIA Karting world championship rounds run under the international federation.
Magnetic strip. A strip buried in the track surface that older lap timers detect to mark the start of each lap.
Transponder. The small onboard unit that official timing uses to identify each kart as it crosses the loop; systems from suppliers such as MYLAPS run most race timing worldwide.
Beacon. A trackside transmitter, or a GPS-defined line, that tells your own logger where the lap starts and ends.
Stint. One continuous run on track, from rolling out to coming back in.
Stint shape. The pattern of lap times across a stint: where they peak, where they fade. A tyre and pressure story told in lap times.
Session sheet. The one-page record of a session: setup, conditions, pressures, lap times, notes. Cheap to keep, expensive to skip.
Debrief. The structured review after a session, with data and video open, done before memory rewrites the run.
Baseline. The known setup and lap time every change gets measured against.
Back-to-back test. Two runs separated by exactly one change, compared directly.
One-variable rule. Change one thing at a time. Change two and the data can’t tell you which one worked.
CSV export. Your data saved as plain comma-separated text that any software can open. What to do with it fills the telemetry CSV export guide.
Anonymized data. Telemetry stripped of identifying details so laps can be pooled and compared across many drivers without naming anyone.
AI coaching. Software that reads your data and turns it into plain-language feedback, the job a salaried data engineer does for professional teams, made available to a club driver.
Using this karting glossary
A glossary tells you what the words mean. It can’t tell you which ones matter on a Tuesday test day.
So here’s my order, for what it’s worth. Speed trace, minimum speed, delta time. Those three answer most of the questions a karting weekend asks.
To watch all of this vocabulary working together on real laps, read the karting telemetry guide next. And when a word on a timing screen or a forum makes no sense, come back. That’s what this page is for.
Alessio Lorandi started karting at six and won the 2013 CIK-FIA Karting World Championship. He raced through Formula 3, GP3 and Formula 2 before founding Purpl, an AI data coach for karting drivers.
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