Set the phone level, square to the bike, and pedal. Llyr reads your hip, knee and ankle through the stroke and tells you what to adjust. It's a quick check, not a bike fit, and it won't hand you a number it can't stand behind.
One phone, propped at the sideNothing to strap onReads you as you moveAnalysis runs on the phone
Orange is Llyr's own lines, on the real screen.Degrees are hip, knee and ankle, measured from the side.
A check, not a bike fit.
A proper bike fit is a person, a jig and a couple of hours. Llyr is not that, and saying otherwise is the fastest way to lose a rider who knows the difference.
What a phone can do is check. It watches a few pedal strokes from the side and tells you whether your saddle looks high, low or about right, and which way to move it.
Can see
Knee angle at the bottom of the stroke
This is the angle saddle height actually depends on, and it is clear from the side.
Can see
Hip, knee and ankle through the whole rotation
Watched over several strokes, so one odd pedal turn doesn't decide it.
Can see
Which way to move, and roughly how far
Up a little, down a little, or leave it. You get it when you stop, not shouted at you mid-effort.
Can't see
A saddle height in millimetres
A phone camera can't measure millimetres, so that number would be invented. Same for setback and reach.
Can't see
Power, torque, or a knee-tracking verdict
Power needs a power meter. Watching your knees track needs a camera in front of you. One phone at your side is neither.
Mid-2026Bike Fit is the check this page describes. Pedalling technique
still isn't built. Run and Golf read “soon” in this shot
— both have shipped since.
Set it up in a minute.
1
Square it up
Phone level, straight at the side of the bike, the whole pedalling leg in shot. Llyr tells you when it's off.
2
Pedal
Pedal steadily on a turbo or anything that holds the bike still. Llyr counts the strokes as you go.
3
Adjust
The read comes when the check finishes, with a photo of each thing it flagged. Move the saddle, run it again.
Lines you can argue with.
Reference lines you can see
The straight-down lines and the angle arcs are drawn on your own video. If the read looks wrong, you can see why.
Several strokes, not one
Llyr waits until it has watched enough pedal turns to be worth reading.
Told at the end, not during
Nothing shouts at you while you're pedalling. The read is delivered once, when you stop.
Kept, so you can compare
Every check is saved with its photos, so the next one shows whether the change did anything.
What we can promise today.
In early access
No rider has used this long enough to quote, so there are no reviews here. When there are real ones, they'll carry real names.
A check, and only a check
This doesn't replace a bike fitter. It tells you whether your position is worth a second look, which is a smaller thing to claim and a true one.
No millimetres
Llyr won't give you a saddle height, a setback or a reach figure. It leaves those out on purpose, not because nobody got round to them.
Judge it yourself
Join the list, check your own position, and hold it against what a fitter has already told you.
See your position from the side.
Join the early-access list. Sign up here and cycling is what you'll hear about.
100Seats in the first group
That is the whole of it. We would rather have a hundred people
actually filming and telling us what broke than a list of ten
thousand who never open it.
No spam. Just an email when there's something to try.
