"Racing Circuit Lap Timer" is a lap timer for racing circuits using the GPS function of iPhone.
You can easily measure lap times and sector times with iPhone.
Approx. 40,000 laps of measured lap times are saved and can be viewed and shared.

(Measurable circuits) Planned to be added in the future.
(Japan)
Asan Circuit
Auto Land Tsukude
Autopolis Racing Course
Central Circuit
Chiba Kita Pocket bike Course
Ebisu Circuit East Course
Fuji International Speedway Racing Course
Hero Sinoi Circuit
Honjo Circuit
HSR Kyusyu Circuit Course
Ipponkunugi Speedway (ccw)
Ipponkunugi Speedway (cw)
Iwai Circuit Road Course
Keiyou Speed Land
Kota Circuit
Ksk Circuit
Mihama Circuit Full Course
Mobara Twin Circuit East Course
Motegi Road Course (Full)
Narita Motor Land (ccw)
Narita Motor Land (cw)
Nihonkai Maze Circuit
Nikko Circuit
Okayama International Circuit
Okegawa Sports Land
Sodegaura Forest Raceway
Southern Circuit
Sugo International Racing Course
Spa Nishiura Motor Park (Forward)
Spa Nishiura Motor Park (Reverse)
Suzuka Circuit Racing Course
Suzuka Circuit South Course
Takasu Circuit
Tokachi Speedway Clubman Course
Tokachi Speedway Grand Prix Course
TS Takata Circuit
Tsukuba Circuit Course1000
Tsukuba Circuit Course2000
Tsukuruma Circuit Nasu
(France)
Circuit Paul Ricard
(Taiwan)
Lihpao G2 Circuit
(United Kingdom)
Donington Park Circuit
(United States)
Blackhawk Farms Raceway
Laguna Seca
Waterford Hills Road Racing

(About mounting the iPhone)
- Mount the iPhone to the machine where the iPhone screen can be seen by the driver/rider.
- For 4-wheel machines, GPS reception is more stable under the windshield than under the roof.
- If you don't need to see the time while driving, you can put the app in stand-by mode and put the iPhone in your pocket.

(iPhone settings)
- Turn on Location Services.
- Allow LOCATION ACCESS to LapTimer.
- Turn on Precise Location.

(How to use)
1) Tap the "Settings" button at the bottom center of the screen to open the settings window. Select the circuit you want to measure. You can also select the speed unit and reset the best lap time in the settings window.
2) Tap the "Start" button at the bottom right of the screen to enter stand-by mode, the timer section at the top of the screen will display "Measurement will start when crossing the finish line", and the button will change to “Cancel/Stand-by". GPS is working when the speedometer on the screen changes to numbers.
3) When you enter the course and pass the finish line at a speed of 30km/h / 19mph or more, the timer at the top of the screen will start running and measurement will start, and the "Cancel/Stand-by" button will change to the “Stop" button.
4) After that, the lap time will be updated every time you cross the finish line. The sector time is also updated each time.
5) When you finish running and tap the "Stop" button, the measurement will end and return to stand-by mode, and the button will change to "Cancel/Stand-by".
6) Tap the "Cancel/Stand-by" button to exit stand-by mode and the button will change to “Start".
7) Tap the "Results" button at the bottom left of the screen when the button at the bottom right of the screen is "Start" or "Cancel/Stand-by" to display all saved results. Best/2nd/3rd lap times and top speeds are also easily visible. You can select the part you need and copy or share it.

Please see "App support” about followings.
(About screen display)
(About the measurement line)
(Note)

The developer assumes no responsibility for any accident, violation, loss or claims by third parties which may arise from the use of this app.