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.

Main Features

• No setup or calibration is required! Mount and go!
• Automatic recording; simply open the app to the Recorder screen and go!
• HD Video on devices that support it [In-App Purchase]
• Cloud sync data across all devices [In-App Purchase]
• GoPro action camera auto on/of and auto record [In-App Purchase]
• Real-time display of speed, g forces, and lap times
• Immediate analysis of performance data and video at the track [In-App Purchase]
• Lap and segment times
• Horsepower graph
• Automatic track mapping; no need for predefined track info
• High resolution GPS (up to 20Hz) using an external GPS module
• OBD2 data recording (using optional OBD2 modules) [In-App Purchase]
• 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, and AirDrop
 • Share and compare lap times using the CMS Cloud Service
 • Export CSV for use with other apps such as Track Attack or RaceRender [In-App Purchase]

The Pro version includes all of the above in-app purchase options at a reduced price.

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:

• Also Available: CMS Lap Timer Pro for iOS

CMS Lap Timer Pro includes all the features above that are in-app purchases

• 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

5.0 out of 5
4 Ratings

4 Ratings

Colorado Sandy ,

Handy track app

Used this app for several years. Helpful for driver feedback optimizing lap times. Recently updated iOS on my 4S phone and the app stopped working. Sent an email to the support link on the outside chance someone was still monitoring the site. Pete responded in in less than an hour. He debugged the new iOS library issue and just sent out the update. Wow.

hirkophoto ,

Nice Lap timer!

First let me start by saying I don't do App reviews, this is my first.
I got this App (free version) and figured what do I have to loose if it does not work. Well I was pleasantly surprised that it worked great. You do need to have your phone firmly mounted for it to function correctly. I have used it several times at two different tracks. Willow springs raceway in CA and Spring mountain ranch in NV. The app worked great every time. The only problem experienced was my iPhone overheated and shut down at Spring Mountain. The problem was not App related. My lap times where all recorded each session I ran. When I reviewed them I could used the data to compare lap times which is a really cool feature once you learn how to use it. I could see my fastest lap displayed for me on each session I ran. I also exported the files though iTunes and used the free CMS software to analyze data on my desktop. Pretty slick and it's all been Free!
Plus when I want I can pull my phone out and show my buddies my lap times and data any day of the week. I emailed CMS support to request they allow exporting of a plain text file or excel file so I can print and keep records of my laps. They returned emails the same day and are working on including that in the next software update. I have not even tried the video yet!!

Cal... ,

It works great

So many gps lap timers either don't work at all, or are a PITA. When I go to the track, I'm on a motorcycle and I don't want to mess around with my phone on my handlebars trying to get a start/stop point. This app is the first app I've used that makes it so you can just go ride, then come back and review your times. Of course with the blessing of automated track learning/timing, you may get an incorrect time for the first lap or two as it learns and creates a start/stop, but after that it looks to be pretty darn accurate. Great app, wouldn't recommend any other gps lap timer, this is the one to have!


Pete Stoppani Consulting
18.3 MB

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



Age Rating
In-App Purchases
  1. Data Analysis
  2. Video w/ Data Overlay $9.99
  3. OBD2 Data $9.99


  • Family Sharing

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

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