Useful Triathlon Apps & Tools

I’d like help to compile a useful list of triathlon apps, other than the ‘main’ ones like Garmin’s or Strava. So, for example, I’d be interested in a tyre circumference calculator based on tyre size.

1. Here is one to work out Heart Rate Training Zones based on LTHR: https://web.archive.org/web/20140814130555/https://play.google.com/store/apps/details?id=com.app2droid.hrzc.base&hl=en
2. Here’s James Driscoll’s pace calculator: http://www.dialsolutions.com/run/
3. Then there are HRV apps like: ithlete, bioforce HRV and Elite HRV.