📐 Range-validated 🔬 Evidence-informed 🔒 Local data only

Know if your bike fits — before it becomes a problem.

Enter your real measurements, see exactly which ones fall inside evidence-based ranges, then optionally add a symptom to pinpoint the most likely cause.

1

Setup

Record your rider profile, real frame geometry, and cockpit specs.

2

Validate

See each measurement scored against personalised evidence-based ranges.

3

Refine

Optionally add a symptom to focus on the most likely culprit. Log every change.

⚠ Important safety note

This tool is not a medical diagnosis and is not a substitute for a professional bike fitter, physiotherapist, or clinician. Stop self-adjusting and seek qualified help for sharp pain, swelling, persistent numbness, radiating symptoms, or symptoms following a crash.

Rider profile

Height and inseam drive personalised range calculations. Fill these accurately.

Body measurements

Height, cm

Cycling inseam, cm

Barefoot floor-to-crotch. Used for saddle-height range calculation.

Riding profile

Experience level

Main riding type

Typical ride duration

Weekly riding volume

Primary goal or concern

Bike & geometry

Frame geometry drives how measurements are interpreted. Not all frames labelled the same size are the same — enter real numbers from your geometry table.

Bike & drivetrain

Bike type

Frame size label

Pedal type

Crank length, mm

Printed on crank arm near pedal thread. Common: 165, 170, 172.5, 175 mm.

Saddle model

Shoe model

Frame geometry

Where to find these: Your frame manufacturer's geometry table (website or manual). Search "[brand] [model] geometry" and look for your size column.

Stack, mm

Vertical height from BB centre to top of head tube. The primary bar-height reference.

Reach, mm

Horizontal distance from BB centre to top of head tube centre. Combined with stem to give total cockpit reach.

Seat tube angle, °

Virtual / effective STA. Steeper angles (>73°) move the saddle forward — more setback needed to find KOPS.

Head tube length, mm

Combined with stack, spacers, and stem rise to determine max bar height.

Cockpit

Handlebar width, mm

Centre-to-centre at the drops. Convert cm to mm: 40 cm = 400 mm.

Stem / cockpit forward reach, mm

Stem length, or for integrated cockpits the forward reach spec. Adds to frame reach for total cockpit distance.

Recent equipment or training changes

Fit measurements

Record your baseline before changing anything. These feed directly into the validation ranges.

Safe adjustment rule: Change one variable at a time. Saddle height: 2–3 mm · Saddle tilt: 0.5–1° · Cleats: 1–2 mm. Retest for 1–2 rides before the next change.

Saddle

Saddle height, mm

How to measure

Centre of BB axle → top of saddle, tape parallel to seat tube.

Too low: front knee pain, cramped feeling, low power.
Too high: hip rocking, back-of-knee pain, toe-pointing.

Saddle setback, mm

How to measure

Drop a plumb from the saddle nose tip. Measure horizontal distance to BB centre. Positive = nose is behind BB.

Too forward: front knee pressure, weight on hands.
Too far back: reaching for pedals, hamstring tension.
Note: steep-STA frames (>73°) legitimately require more setback.

Saddle tilt, °

How to measure

Digital level on the flat sitting surface. Positive = nose-up. Negative = nose-down. 0° = level.

Nose-up (>2°): soft-tissue pressure.
Nose-down (<−2°): forward sliding, hand overload.

Cockpit position

Bar drop, mm

How to measure

Vertical difference: saddle top → hood / bar contact area. Positive = bars lower than saddle.

High drop (>70 mm for beginners): neck strain, shoulder tension, numb hands.

Reach to hoods, mm

How to measure

Saddle nose → hood / bar contact centre. Note which reference you use — hood reach differs from clamp reach by ~60 mm.

Too long: locked elbows, shoulder tension, numb hands.

Cleats

Cleat position notes

How to check

Mark the ball of the foot on the shoe. Compare to pedal axle. Note rotation angle and float.

Problems: foot hot spots, knee tracking discomfort, Achilles strain.

Fit validation

Each measurement scored against evidence-based ranges, personalised to your height, inseam, and experience level.

Symptoms Optional

Use this to refine your validation results. Select a symptom and the app will correlate it with any flagged measurements to show which is most likely the cause.

Symptom details

Main symptom

Severity, 0–10

When does it start?

Side affected

Notes

🚨 Red flags — tick any that apply

Sharp, severe, or worsening pain

Swelling, bruising, heat, or visible joint change

Numbness or tingling that persists after the ride

Radiating pain, weakness, or loss of control

Recent crash, acute injury, surgery, or known medical condition

Fit plan

Symptom-correlated plan. Treat it as a structured test, not a diagnosis.

Adjustment log

Track exactly what changed and whether it helped. Prevents random tweaking.

New entry

Date

Area changed

Old value

New value

Pain before, 0–10

Pain after, 0–10

Ride test notes

Logged changes

Learn the basics

Each section: what it is, why it matters, how to measure it, what to try first.

Fit report

A complete summary including validation results — take it to a fitter, coach, or clinician.

Click "Build report" to generate your summary.