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Free local adjustment tool
Begin with two independent manual readings of your current saddle angle, or optionally calibrate a supported phone from floor to saddle. Choose one 0.5-2.0° nose-up or nose-down move and receive the exact signed target plus the angle needed to reverse it.
Positive means nose-up; negative means nose-down. The calculation does not select a direction from symptoms, prescribe an ideal tilt or promise comfort or performance. No reading leaves the page, and the manual workflow remains available when a sensor is missing, denied or unstable.
Manual baseline - always available
Start with blank readings. Positive means nose-up; negative means nose-down. Lift and replace the same level or inclinometer between readings without changing the saddle reference points.
Optional on-device inclinometer
Keep the phone face up in portrait, with its physical top pointing toward the saddle nose. First sample a hard level floor, then the same phone orientation on the saddle reference. Sensor values remain in this page.
Manual entry above never disappears. Browser support, permission, sensor quality, case shape and saddle curvature vary; use a separate inclinometer if the phone result is unstable or unavailable.
One adjustment only
The 0.5-2.0° cap limits this workflow to one small trial. It is not a recommended fit range or target.
Your target
Complete one baseline method, choose a direction and pass every hardware gate. No symptom, ideal-angle or performance inference is used.
Bike-linked frozen trial
The journal freezes the baseline, target, saddle surface and leveling method for 30 days. Reloading never rebuilds the plan from a changed passport, and final readings always start blank.
Repeatability before adjustment
Curved, stepped and waved saddles can produce different numbers from different straightedge contact points. Name and photograph the reference you use. This assistant compares repeated readings from that convention; it cannot translate the number to another saddle shape or certify the accuracy of a phone sensor.
Level and secure the bicycle. Place the same straightedge, digital level or phone along the same named centreline contact points each time. Record positive for nose-up and negative for nose-down; a different saddle shape or reference is a different measurement.
Lift and replace the tool between two independent readings. Alternatively, use the optional phone workflow: keep the phone face up in portrait with its physical top toward the saddle nose, sample a hard level floor, then sample the saddle. Nothing is uploaded or saved.
If the first two manual readings differ by more than 1.0 degree, take one fresh third reading. The assistant uses the triplet median and keeps the complete spread and observed half-range visible.
Choose nose-up or nose-down and select 0.5, 1.0, 1.5 or 2.0 degrees. This cap defines one reversible product workflow; it is not an ideal angle, symptom response or performance target.
Use the exact saddle and seatpost instructions, supported rail/clamp range, specified torque and an undamaged assembly. Preserve the baseline, change tilt only, verify the final angle twice and check security before a short ride and a 2-3 ride comparison.
What is exact
Nose-up adds the chosen step; nose-down subtracts it. Median, spread and observed half-range expose what the readings actually said. The target remains useful only when the bicycle, saddle reference and sign convention stay unchanged during the final measurement.
What is not inferred
Saddle design, rider position and terrain change how the same displayed angle behaves. The assistant does not turn a sensation, posture or research result into a direction, and a successful calculation is not a mechanical inspection or a performance forecast.
Manufacturer, regulatory and primary sources
Official owner manual - 2026
Trek's owner manual lists saddle-clamp bolts among fasteners that need the correct torque and states that a torque wrench is the reliable way to determine tightness. Use the instructions for the exact saddle and seatpost rather than copying a generic number.
Open the Trek owner manualOfficial manufacturer guidance
Trek describes level as its own bicycle starting instruction and separately warns that some carbon rails require compatible clamps. That manufacturer-specific guidance is a hardware boundary, not a universal angle recommendation for every saddle or rider.
Read Trek's fitting guidanceCompetition context only - UCI 2026
The official UCI road/cyclo-cross mass-event diagram marks a ±9° saddle boundary. It is a competition equipment rule, not a comfort, fit or mechanical-safety target. Racers must verify the current rule, discipline and official measurement convention separately.
Open the official UCI diagramPrimary research - PMID 34766189
Wilkinson and Kram studied 19 healthy recreational cyclists on an 8° uphill treadmill, comparing a saddle parallel to that surface with one tilted 8° nose-down. The authors state that other slopes and the mechanism remain to be investigated. This narrow condition is not a general target or performance promise and is not used by the calculator.
Open the PubMed recordRecord saddle height and fore-aft before touching the clamp, use the on-device camera only after the saddle is mechanically secure, or return to the tools hub without stacking another change into this trial.