Compatibility

Does Derny work with my trainer?

Almost certainly. Derny talks to trainers through FTMS — the open Bluetooth standard — rather than through per-brand integrations, so it drives every compliant trainer the same way.

The short answer. If your trainer supports FTMS, Derny drives it. That covers nearly every smart trainer sold since about 2019. If it pairs as a controllable smart trainer over Bluetooth with any other training app, it speaks FTMS.

Trainer brands that ship FTMS

Brand-level, non-exhaustive, and roughly ordered by how many people actually own them. Most current models from each speak FTMS over Bluetooth. Check your model's spec sheet for "FTMS" or "Bluetooth smart trainer control".

WahooKickr, Kickr Core, Snap, Move
Tacx / GarminNeo 3M, Neo 2T, Flux S, Flux 2
ZwiftHub, Hub One, Ride
EliteJusto 2, Direto XR, Suito, Zumo
JetBlackVictory, Volt
Van Rysel / DecathlonD100
WattbikeAtom (smart bike)
MageneT300, T200, T110
Saris / legacyH3, M2 — discontinued, still work

Plus any other trainer that implements FTMS, listed or not. Saris stopped making trainers, but the H3 and M2 already in the wild speak FTMS and work fine.

Derny is in beta. If your trainer doesn't work the way it should, we'd love to hear about it — email us with the make and model and we'll get it sorted.

Read this if you own one of these

Three places FTMS gets complicated

Wahoo trainers older than about 2020 predate FTMS and are driven by Wahoo's own Bluetooth protocol. Derny can't control those. Anything from the current Kickr, Kickr Core, Snap or Move line is fine.

Smart bikes are a mixed bag. The Wattbike Atom advertises FTMS. Wahoo's Kickr Bike uses Wahoo's own control protocol rather than standard FTMS, so Derny may not be able to set targets on it. If you're buying a smart bike specifically to use with Derny, confirm it exposes FTMS first.

Virtual shifting isn't FTMS. On Zwift Cog trainers — the Zwift Hub One and Ride, JetBlack Victory, Van Rysel D100 — the gear changes run over Zwift's own protocol. Derny sets power and resistance targets, which works normally on all of them; it just doesn't change your virtual gears.

What Derny does with your trainer

Holds a power target (ERG)

Derny sets the watts and the trainer holds them regardless of your cadence. This is how adaptive workouts steer your effort — when your heart rate climbs past its ceiling, Derny lowers the target and the trainer eases off under you.

Sets a resistance level

For trainers that don't do ERG, or workouts written against resistance rather than watts, Derny drives the resistance target instead. It detects which modes your trainer advertises and uses what's there.

Reads power, cadence and speed

Live, every second, straight from the trainer's Indoor Bike Data broadcast — and recorded into the ride file that lands in Strava.

Heart-rate monitors

Any standard Bluetooth heart-rate strap or sensor — Polar, Garmin, Wahoo Tickr, Coospo, Magene, and the rest. They all implement the same Bluetooth Heart Rate Service, and Derny reads it directly. On iPhone, an Apple Watch running the Derny watch app can stream your heart rate instead, no strap needed.

What Derny does not support

Not supported

ANT+

Derny is Bluetooth Low Energy only, on both iPhone and Android. Nearly every trainer and strap broadcasts both at once — pair over Bluetooth and you're fine.

Not supported

Rowers, treadmills, ellipticals

The FTMS standard covers these, but Derny only reads Indoor Bike Data.

Not supported

Trainers that only speak a proprietary protocol

A few bikes and older trainers expose control only through their own vendor protocol. Derny implements FTMS and nothing else, so it can't drive those. If yours shows up in other apps but won't take a target from Derny, that's usually why.

Partial

Power meters and dumb trainers

A Bluetooth power meter broadcasting the Cycling Power Service gives Derny your watts and cadence, so you can ride a workout and record it in full. Derny just can't change the resistance for you — that needs FTMS. Adaptive rules that adjust a target still show you what to do; they just can't do it for you.

Questions people ask

Does Derny work with my smart trainer?

If it supports FTMS — the standard Bluetooth smart-trainer protocol — yes. That covers nearly every trainer sold since about 2019, including models from Wahoo, Elite, Tacx, Saris, Zwift, Wattbike, JetBlack and Magene.

Does Derny support ANT+?

No. Derny is Bluetooth Low Energy only, on both iPhone and Android. Most modern trainers and heart-rate straps broadcast both ANT+ and Bluetooth at the same time, so connect over Bluetooth.

Does Derny work with smart bikes like the Wahoo Kickr Bike or Wattbike Atom?

It depends on the bike. The Wattbike Atom advertises FTMS and should work. Wahoo's Kickr Bike uses Wahoo's own control protocol rather than standard FTMS, so Derny may not be able to set targets on it. Confirm your smart bike exposes FTMS before relying on it.

Does Derny work with older Wahoo Kickr trainers?

Wahoo trainers older than about 2020 predate FTMS and use Wahoo's own Bluetooth protocol, which Derny cannot drive. Current Kickr, Kickr Core, Snap and Move units support FTMS and work.

Does Derny work with rowing machines or treadmills?

No. The FTMS standard covers them, but Derny reads Indoor Bike Data only. It is an indoor cycling app.

What if I only have a power meter and not a smart trainer?

Derny reads power and cadence from any Bluetooth device broadcasting the Cycling Power Service, so you can follow and record a full workout. It cannot control your resistance, because that requires FTMS.

Which heart-rate monitors work with Derny?

Any standard Bluetooth heart-rate strap or sensor, since they all implement the same Bluetooth Heart Rate Service. On iPhone, an Apple Watch running the Derny watch app can stream heart rate instead of a strap.

Does Derny control my trainer's resistance?

Yes. Derny holds a power target in ERG mode, or sets a resistance level on trainers that do not support ERG, using the standard FTMS control point.

Do my rides upload to Strava?

Yes. Connect your Strava account once and every finished ride uploads automatically, with power, heart rate and cadence. Uploads are one-way: Derny sends rides to Strava and never reads your Strava history back.

How much does Derny cost?

Derny is free while it is in beta, on both iPhone and Android.

Trainer on the list?

The beta is live on iPhone and opening up on Android. Free while it lasts.

Join the beta