HeadwindLabWhy I built it
Two power numbers. Only one matters.
My trainer said one thing and my power meter said another. Race day only cares about the power meter, so I made the power meter run the trainer.
Nils
TrueWattERG mode from your power meter · iPhone
Train indoors to the watts you actually race on.
Your smart trainer and your power meter never agree. TrueWatt runs the trainer in ERG mode using your power meter, so the 250 watts you hold inside are the same 250 watts you hold on race day.
- ERG mode driven by your own power meter, not the trainer's estimate
- Load .zwo and .erg workouts and ride them
- Trainer, power meter and heart rate strap connected at once
Download on theApp StoreiPhone · $9.99 once. No subscription.
01
Smooth, not surgy
On a step change it jumps straight to the new target, then trims small errors. Spikes and dropouts get filtered so the resistance doesn't chase noise.
02
Bring your workouts
Import .zwo and .erg files. See the whole profile, scrub through it, then start.
And the rest
Change it mid ride
Nudge the whole workout up or down 1% at a time, skip a step, go back one, or pause.
See what's happening
Power, target, heart rate, cadence and speed, plus a live graph of actual vs target.
After the ride
Average power, NP, max and heart rate. Export a TCX or save it to Apple Health.
Pairs once
It figures out which device is the trainer, the power meter and the HR strap, and reconnects next time.
Questions
Why doesn't my smart trainer match my power meter?
They measure in different places and are calibrated differently, so a few percent apart is normal. If you race on your power meter, training to the trainer's number means your zones are off. TrueWatt fixes that by controlling the trainer from your power meter.
Which trainers and power meters work?
Smart trainers that support the standard Bluetooth FTMS protocol, and Bluetooth power meters. You can also pair a Bluetooth heart rate strap.
Can I use my own structured workouts?
Yes. Import .zwo and .erg files from the Files app.
Does it work with Apple Health?
Yes. After the ride you can save it to Apple Health or export a TCX file.
Is there a subscription?
No. You buy it once.
ERG mode driven by your own power meter, not the trainer's estimate.
Download on theApp StoreiPhone · $9.99 once. No subscription.
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