Reader map
What this page proves
Coordinate measurement and camber sweep. Start here for the build, question, measurement, and closeout proof.
What we are making
A point map, coordinate table, repeated-measurement table, travel sweep, camber curve, and cross-check drawing.
Question answered
How does wheel camber change as one front corner moves through -25 mm to +25 mm of travel?
What will be measured
P1-P5 coordinates, repeated point spread, wheel travel, gauge camber, and coordinate-derived camber.
Proof that closes it
06_datum_photo.jpg, 06_point_labels_photo.jpg, 06_coordinate_table.csv, 06_repeated_measurement_table.csv, 06_sweep_table.csv, 06_camber_curve.png, 06_coordinate_cross_check.png, 06_error_budget.pdf, 06_point_map_drawing.pdf, and 06_summary.pdf.
Camber is how much the wheel leans in or out. Suspension parts make that lean change as the wheel moves. This project measures the points and records the camber change instead of guessing.
Words you need
Project terms
| Term | Meaning on this page |
|---|---|
| Suspension | Parts locating the wheel. |
| Camber | Wheel lean from the front. |
| Datum | Reference origin and axes. |
| Coordinate | X/Z point location. |
| Pickup point | Suspension joint location. |
| Ball joint | Pivot at upright. |
| Strut | Suspension where damper locates wheel. |
| Double wishbone | Upper and lower arm layout. |
| Wheel center | Hub center point. |
| Travel sweep | Moving wheel through stations. |
| Kinematic model | Geometry model predicting motion. |
Capstone framing
Objective, requirements, constraints
| Type | Specific requirement |
|---|---|
| Objective | Measure camber versus wheel travel. |
| R1 | Datum photo before measurements. |
| R2 | P1-P5 labeled and defined. |
| R3 | Coordinate table with repeated readings. |
| R4 | -25 mm to +25 mm in 5 mm steps. |
| R5 | Camber at every station. |
| R6 | Coordinate cross-check at >=3 stations. |
| R7 | Error budget published. |
| Safety | Adult/builder controls lift; hands clear while jack moves. |
Section 01 · Concept
Purpose and required inputs
Every suspension simulation — from a simple spreadsheet to professional multibody software — needs the same starting data: where the pickup points sit relative to a marked reference on the body. This study measures that input on a real vehicle corner and reports it as a table those tools can read.
What it is
Geometry input for a kinematics model
The front-left corner becomes a set of measured coordinates: upper arm, lower arm, both ball joints, and the wheel center, each located from one written reference. A jack then moves the corner 25 mm up and 25 mm down, so the change in wheel lean is observed rather than assumed. Cars with strut front ends use the substitution mapped in Section 02.
Suspension software cannot model a car it has no numbers for. A driveway, $15–25 of tape and flags, and tools already on hand produce those numbers. The two deliverables — a coordinate table and a camber curve — are the same ones a design office buys from a laser scan, at millimeter accuracy instead of laser accuracy.
Actual principle used
Coordinate measurement and camber sweep
Three ideas run through this study: measuring from one fixed reference, treating linked metal parts as a mechanism, and charting wheel lean against travel. Each one produces a physical piece of evidence.
Coordinates
X / Z chassis datum
Points
≥5
Sweep
±25 mm
Output
camber curve
Section 04 · Sequence
Build sequence and checkpoints
The order is: stage the car, remove the wheel, lay the datum, measure the points, run the sweep, plot the results. Five pass/fail checkpoints — each closed by a photo or a data file — define when the study counts as done.
Lift protocol
Support and safety setup
Two rated stands carry the car, set under the factory jacking points or frame rails — never under suspension arms or the floor pan. Rear wheels get chocked, and the whole car gets a firm shake test before any hand goes near the wheel well. During the sweep, the jack moves only the suspension; the stands hold the body the entire time.
Where it leads
Extension to the full vehicle
The same procedure applied to all four corners gives a full-vehicle point set. After that comes compliance testing — pushing on the assembly to measure how much the rubber bushings give. This study's table feeds a front-view spreadsheet model as-is; the full 3-D upgrade adds the third coordinate at each point, the inboard bushing centers, and the tie-rod ends.
Sequence
Measurement sequence
Stage. Park on flat ground, chock the rear wheels, center and lock the steering, then record the fender-to-hub ride-height distance and photograph the setup.
Wheel off. Break the lug nuts loose on the ground, lift, set the stands at the factory jacking points, and remove the front-left wheel.
Datum. Define the chassis origin, snap or tape the X and Z datum lines, write the axis convention.
Label. Tag the arm, ball-joint (or strut), and wheel-center points as P1–P5.
Measure. Jack the corner back to the recorded ride height, then record each point's coordinates into the table against the origin.
Sweep. Step the hub from −25 mm to +25 mm in 5 mm increments, recording travel and camber together at all 11 stations; repeat and average.
Plot. Chart gauge camber versus travel and overlay the coordinate cross-check from three stations.
Package. Re-measure suspect points, reinstall the wheel (lugs to manufacturer torque, typically 90–140 N·m, star pattern, two passes), export photos, table, chart, and error notes.
Acceptance gates — owner: Kohler
Acceptance gates
Risk, judging, and closeout
What can fail and how the result is judged
What could go wrong
| Risk | Control | Failure action |
|---|---|---|
| Lift setup moves | Approved supports, chocks, shake test. | Stop and reset. |
| Hands in wheel well | Hands clear while jack moves. | Stop sweep. |
| Bad datum | Photo origin and axes. | Restart table. |
| Hidden joint center | Consistent method and error note. | Increase error budget. |
| Gauge zero drift | Check before/after sweep. | Repeat sweep. |
| Body lifts | Reduce sweep or qualified spring-removal. | Stop; do not tie body to stands. |
How the result will be judged
| Check | A-level result | Not acceptable |
|---|---|---|
| Datum | All points trace to photographed origin. | Mixed references. |
| Repeatability | Three readings per point. | Single reading. |
| Curve | Camber at every station. | Only endpoints. |
| Model | Measured curve compared with CAD. | No cross-check. |
Data package
Exact closeout filenames
- 06_datum_photo.jpg
- 06_point_labels_photo.jpg
- 06_coordinate_table.csv
- 06_repeated_measurement_table.csv
- 06_sweep_table.csv
- 06_camber_curve.png
- 06_coordinate_cross_check.png
- 06_error_budget.pdf
- 06_point_map_drawing.pdf
- 06_summary.pdf
Senior capstone readiness
Current status: build plan; measurement data pending. A-level requires repeatability, uncertainty propagation, CAD kinematic model, measured-vs-modeled curve, and explicit 2-D limitations.
Definition of done
- Datum and point photos are saved.
- Coordinate and repeat tables are complete.
- Sweep table covers -25 to +25 mm.
- Camber curve, cross-check, and error budget are published.
Section 02 · Method
Measurement procedure
Measurement runs in a fixed order. First the reference point and two reference lines (the datum) go down. Points get labeled, coordinates enter the table, and only then does the jack move the wheel. That fixed order makes the numbers trustworthy — every measurement traces back to marks made before it.
Coordinate setup and labeled points · live model
Front-left corner: X and Z datum lines meet at the chassis origin, P1–P4 mark the arm and ball-joint points, P5 the wheel center, and the arc traces the camber sweep. The datum photo closes checkpoint DATUM-1.
Camber measurement and uncertainty
Camber gauge and coordinate cross-check
cross-check: camber = atan(Δx / Δz) between the upright's upper and lower reference points at −25, 0, and +25 mm
±1 mm reads at each of two points over a ~400 mm gauge length → per-point uncertainty atan(√2/400) ≈ 0.20° (RSS; 0.29° worst case)
camber typically changes 0.5–2° across ±25 mm depending on suspension type → 5–10 stations resolve the fitted curve's trend
The angle gauge is the main data source. As a cross-check, the same lean angle is also computed from the measured coordinates at three stations, and the two methods must agree within the stated uncertainty.
The biggest error is not the tape measure. It is guessing where a joint's center sits inside its rubber boot — a guess that can be off by 2–5 mm, budgeted in ERR-1. Where the curve is flat, sweeps are repeated and averaged.
Datum discipline
Single-origin datum
One origin point and two reference lines — snapped in chalk or laid in painter's tape — go down before any point is measured. The axis rules are written on the data sheet: X points outboard, Z points up, and the origin sits at the frame-rail mark.
Every coordinate in the table refers to that one origin, which is what lets a front-view (2-D) suspension model read the table directly. A full 3-D package needs the third coordinate, inboard bushing centers, and tie-rod ends; those are follow-ons in Section 05.
A grid sheet tapes to the floor under the corner, lined up with the X reference line. A plumb bob hangs from each suspension point, and where the bob's tip lands, the X coordinate reads straight off the grid. The second sheet is the spare.
Origin
1 chassis
Datums
X + Z
Convention
written
Proof
DATUM-1
Point labeling
Point labeling
Tape labels name the points: P1 and P2 for the two inner arm mounts, P3 and P4 for the upper and lower ball joints, P5 for the wheel center. That layout matches a double-wishbone corner, common on pickups and older sedans. The labels stay on through the whole sweep, so every photo, table row, and chart uses one naming scheme.
Most cars have a strut front end instead of double wishbones. On those, P1 becomes the strut's upper mount at the strut tower and P3 becomes the strut-to-knuckle bolt line. Expect a flatter curve — roughly 0.3–1° of lean change over the full sweep, close to the 0.20° measurement floor — so use the whole range and average repeated sweeps.
Travel sweep procedure
Jack-driven sweep: ±25 mm in 5 mm steps
With the car on stands and the wheel off, the jack sits on a wood block under the lower arm, near the ball joint. It first raises the corner to the sweep zero — the height where the fender-to-hub distance matches the parked value written down in step one.
From there the hub steps from −25 mm to +25 mm in 5 mm increments, 11 stations in all, each approached from below so the linkage settles the same way every time. At every station the gauge reads lean angle and the height reads to 1 mm. The sweep runs twice.
Near ride height the jack is holding up roughly the weight of that corner of the car — about 3 kN, or 650 lb. Pushing higher starts to lift the body off the nearest stand.
Do not tie the body to stands. If full upward travel begins lifting the body from the stands, stop, reduce the sweep range, or use a properly planned spring-removal procedure by a qualified adult/builder. If neither is practical, sweep downward from ride height only and say so in the report.
Before the first station, the gauge gets zeroed on a surface squared vertical off the level floor (a phone app calibrates per its own routine). Steering lock gets re-checked before each sweep direction. Body tilt is measured once and subtracted from every reading, and the zero is checked again after the sweep, with any drift written into the error notes.
Zoo / SolidWorks — build this model
Kinematic sketch from measured points
Type the five measured points into a front-view sketch: arms as lines, joints as points, the wheel as one more line. Fix the body-side points, then drag the wheel center up and down 25 mm — SolidWorks sweeps the linkage the same way the floor jack did. Reading the wheel line's angle at each height gives a second camber curve, drawn instead of measured.
Produce one drawing from the sketch: the labeled point map, P1 through P5, with the measured coordinates in a table block. If the drawn curve and the measured curve agree, the coordinate table has passed the hardest check available to it. A working model of this build is embedded just below, and its STL download opens in SolidWorks, Onshape, or FreeCAD.
Runs in: Zoo (free — its Zookeeper agent builds from this prompt, edits by conversation, and answers design questions) · SolidWorks LEO · or by hand from the list above.
The Zoo file goes into the zoo-design-studio-projects folder shown at the top of Zoo’s Projects screen; the build then appears in the Projects list, dimensioned from this sheet. Paste the macro into SolidWorks (Tools → Macro → New) to export every drawing as a web image.
Model
moving sketch
Check
drawn vs measured
Drawing
point map
Works on
any tier
Section 03 · Parts
Parts and cost
Consumables — flags, tape, marker, grid paper — run $15–25; the measuring kit, jack, stands, and chocks are already owned. Starting from zero adds roughly $60–120 for the measuring kit, $35–140 for a floor jack, and $30–50 for a pair of stands.
Bill of materials
Parts and materials
| Item | Qty |
|---|---|
| Vehicle, front-left corner | owned |
| Floor jack — $35–140 if bought new | owned |
| Jack stands, rated — $30–50/pair new | owned |
| Wheel chocks for the rear wheels — ~$15/pair new | owned |
| Lug wrench or breaker bar + torque wrench | owned |
| Ride-height reference block or chassis tape mark | 1 |
| Chalk line for datum lines (painter's tape substitutes) | optional |
| Marker flags / tape labels for pickup points | set |
| Printed 10 mm grid paper | 2 sheets |
| Masking tape | 1 roll |
| Painter's tape for datum and ride-height marks | 1 roll |
| Sharpie marker | 1 |
| Phone or camera on tripod | owned |
| Consumables total | $15–25 |
Tools and environment
Tool list and resolution
Measurement runs on a tape measure, digital calipers, a carpenter's square, a plumb bob or laser level, and a digital angle gauge or a phone level app. All are owned, or roughly $60–120 as a kit bought new; a real angle gauge alone runs $15–35, and the phone app costs $0. Taking the wheel off adds the lug wrench and a torque wrench for reinstall, also owned. A level driveway and daylight for photos complete the setup.
The 15–25 h span breaks down as staging and datum layout 3–5 h, point measurement with re-checks 4–6 h, two full sweeps 4–6 h, and plotting plus error notes 4–8 h.
Time
15–25 h
Cost
$15–25 consumables
Angle
gauge or app
Grid
10 mm
Section 05 · Scope
Scope and next steps
One front corner, treated as rigid metal — that is the whole scope: point positions, plus the wheel's lean at each step of travel. Measuring all four corners comes next, and after that, how the rubber bushings flex under load. Both follow-ons start from this table.
Evidence package
Four deliverables
Setup photos with labeled points, the completed coordinate table, the camber-versus-travel chart, and the assumption and error-source notes ship together as one package.