The Cantrell Motorsports Lap Timer is the app for the race track enthusiast seeking to improve via learning and sharing.

This is the easiest to use GPS-based lap timer, data recorder, video recorder, and performance analysis app available for iOS devices.

The app does not require any track information to function fully right out of the box. Simply mount it in your vehicle and the app uses GPS to automatically learn the track and pick a suitable start/finish location, which can be change later if desired.

This Pro version includes all of the free version's in-app purchase options at a reduced price.

Main Features

• No setup or calibration is required! Just mount and go!
• Automatic data and video recording; simply open the app to the Recorder screen and go!
• HD Video on devices that support it
• Synchronized data across all devices
• GoPro action camera auto on/of and auto record
• Real-time display of speed, g forces, OBD2 data, and lap times
• Immediate analysis of performance data and video at the track
• Lap and segment times
• Horsepower graph
• Automatic track mapping; no need for predefined track info
• High resolution GPS (upto 20Hz) using an external GPS module
• OBD2 data recording (using optional OBD2 modules such as the GoPoint BT1)
• Designed for auto-crossing, road racing, drag racing, karting, motorcycle racing, bicycle racing and more...
 • Data sharing via Bluetooth (device to device at the track!), e-mail, AirDrop
 • Share and compare lap times using the CMS Cloud Service
 • Export CSV files for use with apps such as TrackAttack and RaceRender

Overview of Operation

Recorded data is saved as Runs. Each Run starts when the vehicle exceeds 20MPH/33KPH and ends when the vehicle is moving slowly. The run includes several seconds of data before the recording trigger speed is reached. This way the start of an auto-cross run is included.

External GPS Modules

Due to limitations of the built-in GPS module, the data may suffer from inaccuracy. An external GPS module is recommended for improved accuracy.

Continued use of GPS running in the background can dramatically decrease battery life. Use of a power adaptor is highly recommended.

• Refer to the user guide for additional information:

• Follow us:
@cmslaptimer Instagram Twitter Facebook

What’s New

Version 2.22

+ Rename location support
+ Auto-scale OBD throttle
+ App store review support
+ Help buttons for social media accounts
+ Draw segment beacon lines
+ Bigger fonts for graph values

Follow us:
@cmslaptimer Instagram Twitter Facebook


Ratings and Reviews

1.0 out of 5
1 Rating

1 Rating

Canyon five ,

Almost there

Well for use at the track only it offers the best iPhone interface, but there is only a very limited way of viewing this on the computer. Maxq data is the only option for pc users and the company is no longer in business. Harry's laptimer uses circuit tools on the pc which is much more helpful as it can automatically assign beacons and allow you to change them for equal sectors max speeds or both min and Max allowing you to separate the corners or even break them down into corner entry and exit. Much more helpful IMHO to find the last few tenths around the track.

KeithJOlsen ,

Awesome App

I bought this app to use for auto-x and hill-climbs. It works great! I've only been able to use it for auto-x so far but it is very accurate and give's you all of the information you could ever want about your run. It will tell your speed at any point on the course and G-forces. You have to buy an external GPS receiver to cover for the inadequacies of the phone, but that's a small price to pay to turn your iPhone into a $1000 data logger. It will also auto start/stop the video so you don't have to worry about missing your best run.
Also the developer responds to feedback and emails quickly. You can tell he is very interested in making this the most thorough data logging app possible on the iPhone. I highly recommend this app.

Paul Aerodeck DC5 ,

Great app, but...

One of the greatest app for lap timing. A lot of functions, track curves erc.

But it has very nasty bag. It closes sometime and if you trying to see your track data it lose it totally. You start app again and... where is no lap time of your last tryout...

I'm frustrated :((


Pete Stoppani Consulting
18.5 MB

Requires iOS 9.3 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating
This app may use your location even when it isn't open, which can decrease battery life.


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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