Crux turns FIT ride files into detailed cycling analysis, training trends and practical planning tools — right on your Android phone. No account required. Crux never uploads your rides.

Free while in early access.

AUTOMATIC IMPORT
Connect your free intervals.icu account once and new rides appear in Crux by themselves — original .fit files from Garmin, Wahoo, Zwift, Hammerhead, COROS and more, with your last five years of rides brought in on first connect and no duplicates (an activity-export ZIP covers anything older). Crux downloads directly from intervals.icu to your phone; it still never uploads your rides anywhere.

RIDES
Import FIT activity files — or a whole ZIP export from your cycling computer or another platform. Explore elevation and ride metrics on an interactive chart you can pan, scrub and zoom. Detect climbs automatically, inspect time in gear and power curves, and calculate key training metrics — weighted power, intensity and training load (the metrics many riders know as NP®, IF® and TSS®). Indoor and trainer workouts get a power-first chart, a lap-by-lap table and rep-drift analysis — see your heart rate creep across matched intervals.

Log perceived effort and fuelling after a ride. For rides without a power meter, Crux estimates a comparable training load from duration and effort.

PALMARÈS
Every climb you've ever ridden, matched across rides into one record: every attempt, your personal records, and a per-climb trend that shows whether you're getting faster. Name your local climbs, and new PRs surface the moment a ride is imported.

PERFORMANCE
See trends across your entire ride library: best-effort power over any date range in watts or W/kg, power and heart-rate zones, and your fitness, fatigue and form. Crux estimates your FTP from evidence, not a black box: hold a genuinely steady 35–75 minute effort and that becomes your FTP — a demonstration, not a model, with the time you held it. Otherwise a steady 25–35 minute effort is projected conservatively, or a Critical Power fit of your best efforts decides. Every input is on show — the efforts it used, the model, its confidence — plus a "how long could you hold X watts?" explorer and your FTP's journey over time with an honest trend. Crux keeps a dated history of your FTP, weight and heart-rate settings, so each ride is scored using the values in effect on the ride date. Edit a past value and every affected ride is recalculated.

DURABILITY
Your power curve when you're already deep into a ride. Compare fresh against after 500–2,500 kJ of work — how much of your 1-, 5- and 20-minute power you keep — and open the ride behind every number.

GARAGE
Save bikes with complete 1× and 2× drivetrain configurations, track each bike's odometer, and keep a service history with on-device reminders when maintenance is due or overdue.

TOOLS
Compare drivetrains with a visual gear-range chart. Calculate gear ratios, gear inches, development, speed at cadence, speed versus power, estimated climb time and tyre pressure — tuned to your bike, not a one-size chart.

COURSES
Import GPX routes and plan ahead with a route map, named climbs and estimated climb times at your target effort. Then build a race strategy: declare your bottles, gels, chews, stops and bag drops, and Crux compiles an hour-by-hour plan and audits it — carb rate, dry spells, caffeine, exactly what to pack in each bag. Race strategy is a fresh release we're actively shaping with rider feedback.

PRIVATE BY DESIGN
Crux has no ads, no analytics and no cross-app tracking. It never uploads your rides, training data or bike details — they stay on your phone, and there's nothing for us to sell or share. Analysis and storage happen on your device.

No account. No subscription. Just your rides, read properly.

NP, IF and TSS are trademarks of TrainingPeaks, LLC. Crux is an independent app and is not affiliated with, endorsed by, or sponsored by TrainingPeaks.