1. Before you start

Put your bike on an indoor trainer, a bike stand or rollers, somewhere with room to stand a phone beside it.
Wear fitted clothes if you can, so your knees, hips and elbows are easy to see.
Good, even light helps. Avoid standing the bike in front of a bright window.

2. Pick your view

Side-on is the view to start with. It shows your knee bend at the bottom of the stroke, your reach, your toes, your elbows and your upper body.

From the front shows which way each knee travels as you pedal. Use it for knees moving in or out.

From behind shows your hips on the saddle. Use it for hips rocking.

Stand the phone steady on a tripod, a shelf or a chair, about level with your hips.
For a side-on shot, square the phone to the bike, so the bike runs straight across the screen.
Frame your whole body and both wheels, with a little room around you.
For a front or rear shot, centre the phone on the bike, a few steps away.

Llyr has a Set up the shot screen that walks you through placing, levelling and framing before you film.

Warm up first, then pedal at a steady, comfortable effort, seated, for at least thirty seconds.
Ride the way you normally ride, in your usual hand position.
Film a few minutes if you can. A habit that shows up stroke after stroke is the one worth working on.

You can use a clip you already have. Import it from your gallery into Llyr, trim it to the part you want, and review it there.

Llyr follows your whole body, head to toes, and draws a skeleton over your riding. A correction has to show up more than once before Llyr flags it.

Bike fit nudges are a direction, never a figure in millimetres: raise the saddle a little, film again, and see what changed.

Your video is processed on your phone and isn’t uploaded to us. Llyr is a second set of eyes, not a professional bike fit.

Llyr needs Android 8.0 or newer and a back camera that records at 720p.