Motorcycle Rider Triangle Simulator / no guesswork hidden

Measure the triangle. Understand the tradeoffs.

Explore an explicit two-dimensional rider model using your measured seat, bars, pegs, and limb lengths. Distinguish reach geometry from comfort or control.

No sign-inLocal calculationsEditable assumptionsSource-linked methodology

Your workspace

Illustrative starting inputs. Replace them with your own measurements and evidence.

01 / Set your assumptions

Make it your own.

Every input stays visible and editable.

Your working plan

A transparent rider-triangle comparison.

Computed locally
The entered limb lengths can span this triangle

Joint angles are idealized planar geometry. They do not establish comfort, mobility, footing, steering clearance, or safe control.

Modeled knee angle72.4°Internal joint angle; straight = 180°
Modeled elbow angle72.1°Internal joint angle, not a comfort score
Torso forward lean15°An input assumption, not a predicted posture
Inseam minus seat height20 mmDoes not account for seat width, sag, footwear, or stance

Illustrative side-view geometry

Two-dimensional rider triangle using entered body and control dimensionsIllustrative 2D geometry, not a fit or safety assessment

Before you act

  • A positive inseam-minus-seat-height number does not prove flat-footing. Seat width, suspension sag, pelvis position, boots, and road slope matter.
  • The drawing is an original schematic, not a measured motorcycle silhouette. Exact model-year control coordinates must be measured or sourced.
  • Test control reach and clearance in person with qualified guidance. This model cannot establish comfortable or safe riding posture.

Reach geometry

Hip to footpeg531.41 mm900 mm
Shoulder to handlebar388.72 mm660 mm
Calculation notes & limitations

The law of cosines gives internal joint angle: arccos((segment A² + segment B² − endpoint distance²) ÷ (2AB)).

An endpoint distance outside the sum or difference of segment lengths is marked unreachable instead of clamping it into a plausible posture.

Saving is optional. Files and records never leave your browser through this app.
02 / Look under the hood

The method is part of the tool.

Measure rider limb lengths and the seat-relative handlebar and footpeg coordinates for the exact motorcycle and setup.

Choose a torso-lean assumption and solve the arm and leg triangles using the law of cosines. Mark physically unreachable endpoints explicitly.

Use the schematic to compare input scenarios, not to infer comfort, flat-footing, or safe control. Validate the real motorcycle in person.

Read the full methodology
03 / Know the boundaries

Evidence before certainty.

A two-dimensional diagram cannot guarantee comfort, footing, control reach, clearance, or safe operation. A real-world fit check is essential.

These are reference sources, not evidence that example records have been verified. Imported records retain the source links you provide.

Motorcycle Safety Foundation rider resources
Field notes / Rider Triangle

How Rider Triangle calculates your result

Explore an explicit two-dimensional rider model using your measured seat, bars, pegs, and limb lengths. Distinguish reach geometry from comfort or control.

Rider Triangle: a verification checklist

A useful result is one you can explain, reproduce, and challenge.