This tool will convert a garmin .fit file into a gpx file. The gpx file will contain heart rate and cadence data if present in the fit file. The tool attempts to cope even with corrupt fit files.
My first cycling event was the New Forest Sportive in 2009, after my brother challenged me to do 66 miles faster than he could do 100. Really enjoyed the event, so it became the first of many events, including some BIG rides in Wales and the French Alpes.
For what they are worth, here are my how-to guides for replacing the inevitable worn out parts - where I could not find a guide already on the internet.