Llyr Bike

Film your ride.
See what to change.

Set your bike on a trainer and film a few minutes of steady pedalling. Llyr shows you one thing to change, drawn on your own body.

One phone, beside your trainer. No sensors, no account.

A rider on a bike on an indoor trainer, drawn side-on. Llyr has drawn the rider's joints and bones, circled the knee at the bottom of the pedal stroke, and dashed the knee bend to aim for.
01 / Film

Film on a trainer

Put your bike on a trainer, a bike stand or rollers, and stand your phone at hip height. Llyr shows you how to frame the shot.

Already have a clip? Import it from your gallery, trim it to the part you want, and tap Analyze.

Side-on

Saddle height, reach, toes, elbows, upper body and cadence.

From the front

Which way each knee travels as you pedal.

From behind

Whether your hips rock on the saddle.

02 / Bike Fit

Check your bike fit

Llyr reads your knee at the bottom of the pedal stroke, your hips at the top, your reach and your knee path, then says which way to adjust.

Every nudge is a direction, never in millimetres: raise the saddle a little, film again, and see what changed.

Saddle height

How much your knee bends at the bottom of the stroke.

Fore and aft

Where your knee sits over the pedal with the crank level.

Reach

Your trunk and shoulder angle out to the bars.

Knee path

How straight each knee travels, seen from the front.

Bike Fit comes with a paid Llyr Pro subscription. It is not part of the free trial; ride corrections are.

Llyr is a second set of eyes, not a professional bike fit. If a fitter sees it differently, go with your fitter.

03 / Shoe sizing

Find your bike shoe size

Put your foot on a sheet of A4 paper and point your phone camera at it. Llyr measures your foot against the paper and recommends a size.

For bike shoes it allows a snugger fit than for running shoes. Brands vary, so use it as a starting point and try the shoe on.

Shoe sizing comes with a paid Llyr Pro subscription. It is not part of the free trial.

04 / Corrections

Corrections as you ride

Llyr flags what repeats across your pedal strokes, not one odd moment, and draws it on your own body with one short cue.

  • Saddle high

    Your knee nearly straightens at the bottom of the stroke and your hips reach for the pedal. How to fix it

  • Saddle low

    Your knee stays deeply bent, even at the bottom of the stroke. How to fix it

  • Knee in or out

    Seen from the front, a knee drifts in or flares out as you pedal. How to fix it

  • Hip rock

    Seen from behind, your hips dip from side to side on the saddle. How to fix it

  • Toes down

    Your toes point down hard at the bottom of the stroke.

  • Upper body bounce

    Your shoulders and head bob as you pedal.

  • Locked elbows

    Your arms stay straight and stiff on the bars.

  • Head drop

    Your head hangs low, with your eyes off the road ahead.

  • Hunched

    Your shoulders round up toward your ears.

  • Low cadence

    Your pedal rate, in turns per minute, sits low for the effort.

05 / Your body

Built for your body

Every rider is built differently. Llyr reads saddle height from your own knee range, not one number for everyone, and draws each correction on you.

Private by default

No account and no sign-up. Your video is processed on your phone and isn't uploaded to us.

What Llyr doesn't claim

One phone camera measures body position, not power, force or pedal pressure.

It never makes claims about injury or injury risk.

Works alongside your fitter

Llyr is not medical advice. If Llyr and your fitter or coach disagree, go with them.

Film your next ride.

Llyr is on Google Play for Android phones. Set your bike on the trainer and pedal.

Get it on Google Play

Free to install. One subscription covers all four modules. The 7-day trial covers swim, ride and run analysis; Bike Fit and shoe sizing need a paid subscription.