You’re halfway up a punishing 8% grade, sweat is stinging your eyes, and your heart feels like it’s trying to escape your ribcage. You glance down at your wrist. The little green rings are closing, but is that number actually right? Honestly, for a long time, serious riders laughed at the idea of cycling with apple watch as their primary tool. It was a toy. A glorified pedometer for people who stroll through parks. But things changed around the time watchOS 10 dropped, and if you haven’t looked at the tech lately, you’re probably missing out on the best bike computer you already own.
The truth is, your Apple Watch is no longer just a passive observer of your commute. It has evolved into a legitimate power-meter-syncing, cadence-tracking, heart-rate-broadcasting beast. But there’s a catch. Or several catches, really. If you just hit "Start" and ride, you're doing it wrong.
Why the Apple Watch is finally a real cycling computer
For years, the biggest gripe was the screen. You can't exactly stare at your wrist while bombing down a technical descent at 40 miles per hour. That’s a recipe for a hospital visit. Apple fixed this with the "Live Activity" feature on the iPhone. When you start a cycling workout on your watch, your phone—mounted to your handlebars—basically turns into a massive, high-res display for your watch’s data. It’s seamless. It’s fast.
I’ve seen people drop $600 on a dedicated Garmin or Wahoo unit when they already have a Series 9 or an Ultra 2 on their wrist. It's wild. The watch now supports Bluetooth sensors directly. This is the "holy grail" for data nerds. You can pair your Stages or Vector power meters, your Wahoo speed sensors, and your cadence pods directly to the watch.
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The magic of Functional Threshold Power (FTP)
One of the coolest things Apple introduced is the automatic estimation of your FTP. Usually, finding your FTP involves a "20-minute test" which is basically twenty minutes of pure, unadulterated torture where you ride as hard as you possibly can. It sucks. Apple uses your heart rate data and power data over time to estimate this for you.
It’s surprisingly accurate. DC Rainmaker, arguably the most respected voice in sports tech, has noted that Apple’s power algorithms are holding their own against dedicated high-end head units. When you have your FTP, the watch sets up "Power Zones." This lets you see if you're burning matches in Zone 5 or just cruising in Zone 2 for an endurance base.
The battery life elephant in the room
Let's talk about the Ultra. If you’re riding a standard Series 8 or 9, you’re going to hit a wall. On a long Saturday century ride, a standard Apple Watch might die around mile 60 if you’re using GPS and heart rate continuously. It’s annoying. You’re left with a dead slab of glass and no record of the last two hours of your life.
The Ultra 2 changed the game. It’s chunky, sure. Some people think it looks like a diving computer from a 1980s sci-fi flick. But it gets 36 hours of normal use. In Low Power Mode, which still keeps the GPS and heart rate active but just samples them less frequently, you can get through an entire Ironman. Most of us aren't doing that. We're just trying to make it home before the sun goes down.
If you are using a standard Series watch, turn off the "Always On" display. It's a battery hog. Also, consider a chest strap.
Optical heart rate vs. Chest straps
This is where the nuance comes in. Apple’s heart rate sensor is arguably the best wrist-based sensor on the market. It’s great for steady-state efforts. But cycling is rarely steady. You’re sprinting for a green light, then coasting, then climbing.
Wrist sensors struggle with "cadence lock." This is a weird phenomenon where the watch gets confused by the rhythmic vibration of your arms on the handlebars and starts reporting your pedal strokes as your heart rate. If you see your heart rate jump to 180 while you’re barely breathing, that’s why.
Connect a Polar H10 or a Garmin HRM-Pro to your watch via Bluetooth. The watch will automatically prioritize the chest strap data. It saves watch battery because the green LEDs on the back don't have to fire, and the data is surgical-grade.
The GPS accuracy debate
Apple uses dual-frequency GPS (L1 and L5) in the Ultra and newer models. This is huge for city riders or mountain bikers. If you’re riding through "urban canyons" with skyscrapers or under heavy tree canopy, standard GPS signals bounce around like crazy. Your map will look like a drunk person drew it.
The dual-frequency setup filters out that noise. I’ve compared tracks from an Apple Watch Ultra 2 against a Garmin Edge 1040 Solar, and they are nearly identical. Sometimes the Apple Watch actually snaps to the road faster.
Elevation and the Barometer
One thing people forget is that elevation matters more than distance to many cyclists. Apple uses an internal barometer to track your climbs. It’s sensitive enough to detect when you’ve moved up just a few feet. However, barometers react to weather. If a storm is rolling in, your "elevation gained" might look a bit wonky.
Strava, TrainingPeaks, and the Ecosystem
Let's be real: if it isn't on Strava, did it even happen?
The Apple Health ecosystem used to be a closed walled garden. Now, it’s much more open. You can set the Workout app to automatically sync every ride to Strava. You don't even have to open the Strava app on the watch. In fact, don't use the Strava watch app. It's notoriously buggy compared to the native Apple Workout app. Use the native app, then let it push the data to Strava afterward.
For the data-obsessed, you can also push this data into TrainingPeaks or Intervals.icu. The depth of data—Vertical Oscillation, Ground Contact Time (for runners), and specialized cycling metrics—is all there in the FIT file.
What most people get wrong about "Auto-Pause"
Here is a pro tip: Turn off auto-pause if you’re doing serious training.
Yes, it's nice that the watch stops the clock when you’re at a red light. But auto-pause is notoriously slow to restart. You’ve already cleared the intersection and shifted up three gears by the time the watch realizes you’re moving again. This ruins your average speed and messes with your normalized power calculations. Just leave the clock running. Pro cyclists do.
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Safety features that actually matter
Cycling is dangerous. There’s no way around it. Fall Detection on the Apple Watch is a legitimate lifesaver. It can tell the difference between you dropping your watch on the kitchen floor and you tiding a ditch at 20 mph.
If the watch detects a hard fall and you don't respond, it calls emergency services and sends your GPS coordinates to your emergency contacts. There are documented cases of this saving mountain bikers who were knocked unconscious on remote trails. It’s the kind of tech you hope you never use, but you’re glad it’s there.
Then there's the Siren on the Ultra. It’s loud. 86 decibels loud. If you’re off-trail and hurt, that’s a beacon.
Practical Next Steps for Your Next Ride
Stop treating your watch like a fitness tracker and start treating it like a tool. If you're serious about getting faster, here is exactly how to set up your next ride.
- Get a mount. Buy a cheap Garmin-compatible out-front mount and an adapter for your phone. Use the Apple Watch as the "brain" and your iPhone as the "display."
- Pair a sensor. If you don't have a power meter, get a cheap Bluetooth cadence sensor. It costs $30 and will transform how you understand your pedaling efficiency.
- Customize your screens. Go into the Watch app on your iPhone -> Workouts -> Custom Workouts. Make sure "Power Zones" and "Elevation" are in your main view.
- Check your fit. Ensure the watch band is one notch tighter than usual before you ride. Movement on the wrist is the enemy of heart rate accuracy.
- Sync everything. Open the Strava app -> Settings -> Applications, Services, and Devices -> Health. Toggle everything on.
The hardware is finally there. The software is finally there. The only thing left is the legs. Don't let the "serious" guys in the spandex kits tell you that you need a dedicated computer to be a real cyclist. You’ve got a computer on your wrist that has more processing power than the machines that sent people to the moon. Use it.