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Your report says red — what to adjust first

30 July 2026·7 min read

A report with two red readings is not two problems. It is usually one problem showing up in two places. The order you work in matters more than how much you change, because the contact points are not independent — move the saddle and you have changed reach as well.

Rule zero: if nothing hurts, be sceptical of the urge to change things

The most common way to make a bike worse is to chase a number on a screen when the bike was already comfortable. If you ride regularly, nothing aches, and your report has one amber reading a few degrees outside its band — you are allowed to do nothing. Amber means "worth a look", not "broken".

What genuinely deserves action: a red reading, a reading that matches an ache you already have, or a knee angle well outside 30–40°. Those are worth your afternoon.

The order

Work top to bottom and stop when things are good. Each step can change the ones below it, which is why the order is not arbitrary.

1. Saddle height (free, biggest effect)

This is where nearly everything starts, because knee flexion at the bottom of the stroke is the most reliable measurement in the report and the easiest thing to change. If your knee is reading above about 42°, the saddle is too low; below about 28°, too high.

Move it in 5 mm steps and no more. Five millimetres of saddle height is roughly 2–3° of knee angle, which is enough to see on a re-measure and small enough that your body adapts without complaint. Mark the current height with tape or a pen line on the seatpost first, so you can always get back.

Then re-film and re-measure before doing anything else. Very often the second and third red readings quietly resolve themselves, because a saddle that was 15 mm too low was also tipping your whole upper body into a strange position.

2. Saddle fore/aft (free, often overlooked)

If the knee angle is now good but your torso or shoulder readings are still off, try the saddle's fore/aft position before touching anything at the front of the bike. Sliding the saddle back opens the cockpit; sliding it forward closes it. This is free, reversible, and it changes reach without buying anything.

One caveat: fore/aft also changes your effective saddle height, because the seat tube is angled. Move it, then check the knee angle again. This is the step where people accidentally undo step 1.

3. Bar height (usually free)

If your torso reads too aggressive — much below the 40–50° band and you feel it in your lower back or neck — spacers under the stem are the cheap fix, and most bikes have some already installed that can be moved. Raising the bars brings the torso up and opens the shoulder angle at the same time.

Going the other way, removing spacers to get lower, is worth being careful about. It is easy to put yourself in a position that measures well and that you cannot actually hold for three hours.

4. Cleat position (cheap, if you use clipless pedals)

Fore/aft cleat position changes the effective distance from your hip to the pedal, so it interacts with saddle height. Worth knowing about, but do not start here — and note that the analyzer cannot see your cleats, so this one is judged by feel and by whether your knee angle moves when you change it.

5. Reach — last, and reluctantly

A different stem length is the only item on this list that costs money and cannot be undone in thirty seconds. So it goes last, and only if the first four steps genuinely did not get you there.

Be especially slow to act on the shoulder angle alone. It is the least precise reading in the whole report — it depends on exactly where your hands were on the bars during that clip, and shoulder landmarks are the hardest for a pose model to place. A shoulder angle sitting a little below 80°, with no numbness and no ache, is not a reason to buy a stem. If your hands go numb, or your neck hurts after an hour, that is real information, and it usually shows up in the elbow reading too — locked-out arms near 0° mean you are reaching.

Change one thing, then measure again

This is the part that makes self-fitting work at all. Adjust one thing, re-film, compare. The analyzer keeps your saved results and will show you a before/after table with the change in each angle, so you are not relying on remembering what the numbers were last weekend.

Two changes at once and you learn nothing: if the result improves you do not know which change did it, and if it gets worse you do not know which to undo.

Give each change a real ride before deciding it was wrong. A 5 mm saddle change often feels odd for the first twenty minutes and fine by the end of the ride. Feeling different is not the same as being worse.

When to stop adjusting and see someone

Some things are not fit problems, and no amount of saddle height will fix them:

• Pain that persists after the fit is in range. If your angles are all green and your knee still hurts, the answer is not another 5 mm.
• Sharp or one-sided pain. Fit problems are usually symmetrical and dull. Sharp, or clearly worse on one side, points elsewhere.
• Numbness that does not go away when you get off the bike.
• A leg-length difference, an old injury, or a specific goal like a long TT position. These need a person in the room.

A physiotherapist for the pain, a professional fitter for the position. This tool is built to find the obvious, cheap-to-fix problems before you spend money — not to replace either of them.