Body & Bike Data
Enter your body measurements and current bike setup, then save to open the Single-Bike Sandbox.
TT requires manual saddle measurements for each bike. Enter measured saddle height and setback in that bike's TT Saddle Position section, with its current crank length and seatpost setting. Inseam cannot supply a TT saddle height.
Reference Frame & Cockpit
From the geometry chart (often listed as effective or virtual STA). It places the estimated saddle; it never moves the bars.
Bottom bracket centre to saddle top, as set by the seatpost. One value shared with the rider bar, the transfer tape measurements and the body model.
▸ How this is estimated
- The saddle point runs up the seat tube line from the BB at the seat tube angle for your saddle height, then back by the seatpost setback. It is the saddle top where the post clamps, not the nose, and saddle rail position is not modelled.
- Hood / grip position comes from the frame, spacers, stem and bar only. Seat angle, seatpost and crank length do not move it.
- Effective reach and stack adjust that position for the saddle (seat angle, seatpost setback, cranks) and bar width, so bikes with different saddle positions compare like for like.
- A missing seat tube angle is taken as 73.5°, the angle the tool always assumed, until you enter one. Geometry charts quote the angle at one saddle height; this is a straight-line approximation for a starting setup, not a bike fit.
TT Saddle Position — Manual Measurements
Mark one reference point on the saddle top. Measure height from the bottom bracket (BB) centre to that point, and horizontal setback to the same point, with the current crank length and seatpost setting. Re-enter height after a crank change and setback after a seatpost change. No automatic saddle estimate is used.
Horizontal measurement: positive is behind BB; negative is forward. Include the fitted seatpost and saddle rail position in this measurement.
Optional horizontal offset from the measured saddle reference to your pelvic contact point: positive forward, negative back; 0 uses the reference point. Do not repeat the seatpost setback here.
Enter manual measurements to resolve saddle X/Y, saddle-to-pad drop and reach.
These controls adjust parts relative to the selected stem and basebar. They are local hardware travel, not frame reach/stack limits. Changing frame size or stem moves the total pad coordinates shown in Live Telemetry.
Enter frame and stem geometry to see the BB coordinates covered by this local travel.
Measured vertical height from the stem's bar-clamp centre to the armrest mount base, excluding adjustable risers and pad foam. The mount sits on top of the bar, so the minimum is 16 mm. Verify the frame-specific cockpit mounts, permitted risers/offsets and clearances with the manufacturer before assembly.
Extra height above the fixed mount. Mount height and pad foam are added separately to Total Pad Stack.
Pad centre offset from its mount. Negative moves back; positive moves forward.
Horizontal distance from the stem's bar-clamp centre to the armrest mount. Stem length is adjusted separately.
Live Telemetry Readout
Against the requested position:
Requested Position
Use the effective seat tube angle from your bike's geometry chart. The same value as the Sandbox bike's seat tube angle.
Candidate N+1 Setup
From the geometry chart (often listed as effective or virtual STA). It places the estimated saddle; it never moves the bars.
▸ View Steerer Vector Trigonometry
These controls adjust parts relative to the selected stem and basebar. They are local hardware travel, not frame reach/stack limits. Changing frame size or stem moves the total pad coordinates shown in Live Telemetry.
Enter frame and stem geometry to see the BB coordinates covered by this local travel.
Measured vertical height from the stem's bar-clamp centre to the armrest mount base, excluding adjustable risers and pad foam. The mount sits on top of the bar, so the minimum is 16 mm. Verify the frame-specific cockpit mounts, permitted risers/offsets and clearances with the manufacturer before assembly.
Pad centre offset from its mount. Negative moves back; positive moves forward.
Extra height above the fixed mount. Mount height and pad foam are added separately to Total Pad Stack.
Horizontal distance from the stem's bar-clamp centre to the armrest mount. Stem length is adjusted separately.
▸ How this is estimated
- Both bikes use your one saddle height. The saddle point runs up each seat tube line at that bike's seat tube angle, then back by its seatpost setback.
- Hood / grip position comes from the frame and cockpit only; seat angle does not move it. Effective reach and stack include the saddle difference, so the solver places the bars where the saddle-to-bar reach and drop match.
- A missing angle is taken as 73.5° and marked as assumed. An approximate starting point: a numerical match does not guarantee comfort or that the parts fit.
TT Saddle Position — Manual Measurements
Mark one reference point on the saddle top. Measure height from the bottom bracket (BB) centre to that point, and horizontal setback to the same point, with this bike's current crank length and seatpost setting. Re-enter height after a crank change and setback after a seatpost change. No automatic saddle estimate is used.
Horizontal measurement: positive is behind BB; negative is forward. Include this bike's fitted seatpost and saddle rail position in the measurement.
Optional horizontal offset from the measured saddle reference to your pelvic contact point: positive forward, negative back; 0 uses the reference point. Do not repeat the seatpost setback here.
Enter manual measurements to resolve saddle X/Y, saddle-to-pad drop and reach.
Live Coordinate Audit
±10 mm reach and height around the requested position
Try builds:
Requires complete Panel 1 biometrics for precision fit