Out of range. Never out of touch.
Your group talks, chats and shares one map with zero bars — phone to phone. Plus workouts, offline navigation and smart-trainer control. Free.
Free, paid for by ads. Nothing to buy. · No account needed.
Also on Android Also on iPhone Planning at a desk? Open the web planner →
This is the moment other apps go quiet.
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The group splits on the descent.
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Lose the signal.
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Keep the group.
Everyone still hears you. And sees you.
Your group, in your ear. No signal. No server.
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Talk hands-free
Unmute and the group hears you. Push-to-talk if you prefer.
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One live map
Everyone’s dot, on every phone. See who’s behind.
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Words, too
What you say is typed into the chat, so a rider out of voice range still reads it.
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Stretches with the group
Up to 200 m rider to rider, and further as phones relay it down the line.
Join in five seconds: scan the leader’s QR code. No account.
Voice: iPhone 12 or later on iOS 26.4+ with other iPhones; Android 13+ with Wi-Fi Aware with other Androids. Map, chat and photos work between any phones. Range varies with terrain. Encrypted between phones — nothing reaches us.
Say it. It’s written down.
Hands on the bars, gloves on. Tap once and talk — the gate, the water, the bad corner — and it’s a note. On your phone, nowhere else.
Everything else the ride needs.
Got 45 minutes? Here’s your loop.
- Loops from your door, sized to your time
- Every turn called, on maps for anywhere on Earth. No signal needed
- Wandered too far? Tap back — home by the time you set
- The weather, wind and air quality you’re heading into
You pedal. It sets the watts.
- ERG control of your smart trainer
- Workouts scaled to your fitness, indoors and out
- Build your own, down to the interval
- On your wrist with Apple Watch. A mix matched to every interval’s cadence (iPhone)
Rest day or hard day? It knows.
- Readiness from sleep, HRV and stress
- Every session analysed — power, pace, zones
- Fitness and fatigue over time
One app, not five.
- Bike intercom
- Trainer app
- Route planner
- Recovery tracker
- Offline maps
All in Kardiacs. Free.
Plan it big. Ride it small.
160 mi·19,045 ft·48% air drag
The planner solves the route the way the road will: climb, wind on every stretch, your tyres, your position. It’s on your phone before you clip in.
More room at a desk.
Everything you set up here is on your phone at the next sync.
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Workout builder
Blocks of a zone, not fixed watts. They resolve to your fitness when you ride.
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Fitness and fatigue
Your training load and power curve, month by month.
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Every ride, analysed
Power, heart rate, cadence and climb, with every chart scrubbable.
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Your kit
Every bike’s weight and sensors, so the planner’s numbers are yours.
Where you ride stays yours.
- Your GPS tracks never leave your phone.
- Health data is read on the phone, never uploaded.
- Group rides go phone to phone. We can’t hear them, because they never reach us.
“I spent years building maps and AI at Google, Uber and Microsoft. Kardiacs is the ride app I wanted and nobody had a business case to build.”
Why is it free?
Free, paid for by ads. Nothing to buy. The ads pay for the maps and servers.
Ride in a minute.
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Download. No account, no sign-up wall.
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Tell it your age and weight — or connect Health — for zones from day one.
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Pick Explore, Commute or Indoor. Go.
Bringing history? Import your Strava or Garmin archive, or any FIT file.
Questions
Is it really free?
Yes. Ads pay for the maps and servers. There is no paid tier and nothing to buy.
Do my friends need the app too?
Yes — it is phone to phone. They join by scanning your QR code, with no account. Riders can be up to 200 m apart, and further as phones relay it along the group.
Does it work on Android?
Yes. The map, chat and photos work between any phones running Kardiacs. Group voice works iPhone to iPhone (iPhone 12 or later, iOS 26.4+) and Android to Android (Android 13+ with Wi-Fi Aware).
Does it work with my trainer, watch or bike computer?
Bluetooth FTMS and Wahoo smart trainers, power meters and heart-rate straps pair directly. There is an Apple Watch app. Routes and workouts go out to your bike computer, and the rides it records come back in.
Do I need an account?
No. There is no sign-up wall. Sign in with Google or Apple only when you want your history, routes and gear to follow you between devices and into the web planner.
