About

Road cycling is one of my favorite hobbies and I train almost every day. My bike is equipped with a power meter, and I use power and heart rate as my main indicators of effort — both during rides and when reviewing workouts afterward. I've been running a Garmin Edge for all of that for years.

After holding out for a long time, I finally got an Apple Watch. What stopped me for so long was its incompatibility with most fitness equipment. I wanted it for fitness, but I can't connect my power meter to it, so switching to Apple Fitness wasn't really an option. I use the Watch alongside my Garmin, not instead of it.

The thing that bugged me: I was already wearing the Watch on every ride, but I was still strapping on a separate Garmin HRM chest strap just to get heart rate on my Edge. The Watch measures heart rate perfectly well. It felt ridiculous to carry two devices for one job.

Searching around, the only solution I found was a $60 piece of hardware called Watchlink that you strap onto your bike. More stuff. More batteries. Not what I wanted.

Being a developer, I figured there had to be a software way. After a quick feasibility study, I found that it was possible — just not straightforward. Apple doesn't allow certain Bluetooth functionality directly on the Watch, so the iPhone acts as a bridge: it reads heart rate from the Watch and re-broadcasts it over BLE, exactly like a chest strap would. Your Garmin, Wahoo, or Karoo never knows the difference.

I built the whole thing for myself, honestly without much ambition for it going further than my own rides. But after getting a lot of positive feedback from other cyclists, I put it on the App Store properly.

The design philosophy was — and still is — to keep it simple. No duplicate workout tracking, no heart rate zones, no extra features that just get in the way of what your cycling computer already handles. Just reliable heart rate data, running quietly in the background while your iPhone sits in your back jersey pocket.

I've used my Garmin HRM chest strap exactly once since building this app.