KartPace guides
How to time multiple karts from one phone
You do not need a transponder to compare two or three karts in practice. A parent, coach or mechanic with a phone and a good spot can do it. This guide covers how to set up, how to tap, and what to expect from the numbers.
Pick a spot you can see the whole line from
Stand where you can see every kart cross the line without anything blocking your view. The pit wall or the fence near the start and finish line works at most tracks. Stay behind any barrier the track asks you to stay behind, and ask the track staff if you are not sure where timing helpers may stand.
Face the track, not your screen. You are watching for the kart, and the phone is only where your thumb goes. Look at the line, tap, then glance down.
Choose one fixed reference point
Pick one object on the line and use it every lap. A painted mark, a cone, a post or the edge of a sign all work. Say it out loud before the session: "I tap when the front of the kart passes the post."
The exact point matters less than using the same one. If you tap at the post on lap 1 and at the pit entry on lap 2, the lap time includes your change of spot, and it tells you nothing about the kart.
Tap at the same point every lap
Keep your tap consistent: same point on the kart (the nose is easiest to judge), same reference object, same hand. With one or two karts, tap straight on the kart. With three or more, learn the order they are running in and keep your eyes on the line, not on the screen.
Your tap will be a little late, because you see, decide and press. That is fine if you are late by about the same amount every lap, because the delay cancels out when you subtract one tap time from the next. Big, uneven errors are what spoil a lap time.
Do a few warm-up laps first. Practise on the cool-down laps or on a quiet session so your rhythm settles before the laps that matter.
Missed laps and double taps
You will miss a tap sometimes, especially with several karts crossing close together. When that happens, the next lap time looks about twice as long as normal. Do not trust it. Mark it as a missed lap or add an estimate, and keep estimated laps separate from laps you timed yourself.
If you tap twice by mistake, remove the extra tap straight away. A tiny lap time that is far below anything the kart can do is almost always a double tap.
Pit stops and in-laps
A kart that pulls into the pits will show a long lap. That is not a pace problem, so leave it out when you compare. Note it at the time, and check any very long lap against what you saw before you use it. The lap after a pit stop (the out-lap) is usually slow as well.
Why manual times differ from a transponder
A transponder sits on the kart and a loop in the track reads it, so it records the same point every lap with very little error. A person tapping a screen cannot match that. Your reaction time, your angle to the line and the kart's speed all add error.
What this means in practice: use manual times to compare laps, drivers and changes across a session, such as a tyre pressure or gearing change. Do not use them to settle who won, or to compare your numbers directly with the track's official results. If the two disagree by a few hundredths or tenths, use the track's published results for official comparisons.
A simple routine for a session
- Agree the reference point before the karts go out.
- Write down who is on which kart and what they are trying to test.
- Tap at the same point every lap and watch the line, not the screen.
- Fix missed or double taps right away, while you remember what happened.
- After the session, compare average and best laps, and ignore pit laps.
Where KartPace Timer fits
KartPace Timer is a manual lap timer we are building for iPhone and Android. You tap a driver's card as each kart passes the line, and it handles two to six karts from one phone, offline and without an account. It is not released yet and we have no release date. If you would like an email when your version is ready, join the waitlist. You can read more on the KartPace Timer page.