Rules Desk
ISBD / All-American rule book
A practical reading map for the current online International Soap Box Derby rule book, division plans, clarifications, inspection standards, and race-day authority.
ILLUSTRATED RULE WORKFLOW
Permanent work follows the official authority path.
A shop method can organize, photograph, seat, or recheck an approved assembly. It cannot authorize a new hole, epoxy location, filler area, laminate, axle operation, fastener, or torque.
WHICH DOCUMENT CONTROLS
Read the whole rule stack.
The 2026 Race Week resources page currently labels a PDF revised June 2025 as the 2026 ISBD Rule Book. That book works with the latest division build plan, published amendments and clarifications, inspection forms, event procedures, and the officials' interpretation. A garage technique is never authority.
- Open the current Race Week or Racing Commission resource page.
- Download the rule book linked there, even if an older copy is already in your binder.
- Open the live division hub and use its current plan link.
- Check season changes and division-specific amendments.
- Ask the local director or chief inspector about ambiguity before altering a part.
CORE 2026 SNAPSHOT
Use these as navigation, not as a substitute for inspection.
| Division | Age window | Combined race weight | ISBD distribution |
|---|---|---|---|
| Stock | Effectively 7-13 | 198-200 lb | No more than 15 lb nose- or tail-heavy |
| Super Stock | Effectively 9-18 | 238-240 lb | No more than 15 lb nose- or tail-heavy |
| Masters | Effectively 10-20 | 253-255 lb | No more than 15 lb nose-heavy or 5 lb tail-heavy |
| Legacy | Effectively 12-20 | Maximum 275 lb | Current Legacy plan and event inspection control |
Exact birthday cutoffs and qualification rules matter. Read the official text before registering rather than relying on the simplified age windows above.
COMMON INSPECTION FAILURES
If the plan does not allow it, do not assume it is legal.
- Unauthorized floorboard, shell, axle, spindle, or hardware alteration.
- Loose, concealed, structural, suspended, cantilevered, chained, or movable ballast.
- Unapproved wheels or any wheel alteration.
- Driver position or weight distribution that changes between scale and inspection checks.
- Electronics or communication equipment concealed on or in the car.
- Lubricant use, wheel spinning, or unauthorized cleaning after racing begins under current clarification language.
Leave inspection margin. A home scale, humidity change, different clothing, and scale calibration can move a car that was exactly at the garage maximum beyond the race limit.
THE RULE-FIRST DECISION
Classify the instruction before touching the car.
OFFICIAL PLAN / RULE
Printed permission
The current plan names the part, operation, location, material, stack, or option and shows how it remains inspectable. Follow that exact division step.
SHOP PRACTICE TO CONFIRM
Process, not alteration
Photos, part bins, cable seating cycles, fastener maps, duplicate checks, and measurement logs help repeat the approved build without changing a controlled part.
EXPERIMENT
One permitted choice
A legal posture, route cue, or ballast position can be compared only after its rule authority, baseline, lane, wheels, and conditions are recorded.
Absent, ambiguous, or conflicting is not permission. Stop before cutting, drilling, gluing, filling, laminating, bending, polishing, substituting, or enlarging. Send the exact car, division, event, document link, page or figure, and proposed operation to the authorized rules authority and keep the written clarification.
DIVISION GATES AT THE BENCH
Ask the division question again at every irreversible step.
| Question | Stock / Super Stock | Masters | Legacy |
|---|---|---|---|
| What is the base? | Official kit, branded floorboard, shell, axles, and plan hardware. | Official kit structure and only the current listed options. | Plan-controlled chassis with a custom body path inside its envelope. |
| Can I add a hole? | Only a hole or location the current plan expressly directs. | Only its exact shell, access, running-gear, weight, and attachment instructions. | Only where the Legacy plan permits and inspection access remains. |
| Can I add epoxy? | Only the exact plan-authorized bushing or assembly location; never float a bushing or epoxy a kingpin. | Only the current plan's named bushing, plate, bolt, or shell area, with every exclusion observed. | Only inside the Legacy material and construction method that has been confirmed. |
| Can I use filler or glass? | No assumption. Super Stock seam finish does not authorize structure; current Stock web guidance controls its no-paint path. | Bondo is restricted to listed exterior areas. Fiberglass or carbon structure is prohibited except authorized repair. | Custom fiberglass or carbon work belongs here only when the current Legacy plan permits the full method. |
| Which swap procedure? | Use the sanction and event rule. ISBD's current progressive sequence must not be silently imported into NDR. | ||
INSPECTION FAILURES AS BUILD LESSONS
Use official rejection patterns to plan checkpoints.
Cable wrap is wrong
Do not tighten around the mistake. Return to the division plan's routing figure, rebuild the wrap and clamp sequence, seat the system through normal travel, then recheck neutral and axle state.
Brake bolt was recessed
An unauthorized floorboard recess cannot be justified as neat workmanship. Use the plan hardware and surface condition; obtain an official repair path for an altered board.
Shell hole was enlarged
A loose body screw is not permission for a larger hole or different fastener. Stop and ask for the approved repair before the shell loses inspectability or fit.
Excess epoxy hides an interface
More adhesive is not more legal. Preserve removable plates, visible logos, threads, washers, nuts, and the exact no-fillet zones in the current plan.
Filler corrects the required shape
Masters filler may smooth only listed exterior areas. It cannot create nose height, sharpen a tail, conceal a hinge, or replace plan-correct shell assembly.
Washer stack looks close
“Close” is not an inspection state. Compare every interface with the correct plan image and inventory each leftover part before controls are covered.
Open the complete build-from-scratch course Open driver training
SOURCES & FURTHER READING
Check the primary material.
- ISBD 2026 Race Week resources Official page identifying the rule book and current championship resources.
- ISBD Rule Book - linked for the 2026 World Championship Official PDF currently linked from Race Week resources; the file itself says revised June 2025.
- ISBD race divisions and build plans Official division descriptions, age bands, weights, plans, and Legacy information.
- ISBD 2025-26 build-plan and wheel-swap changes Official season-specific changes; check it alongside the rule book and build plan.
- ISBD Racing Commission clarifications Official updates and approved clarification language, including current wheel procedure rules.
- ISBD Stock car build plan Official Stock assembly plan currently linked from the live division hub. Reopen the live hub before building in case its plan link changes.
- ISBD Super Stock car build plan Official Super Stock assembly plan currently linked from the live division hub. Reopen the live hub before building in case its plan link changes.
- ISBD Masters build plans, July 2026 Current official build plan linked from the division hub. Use it directly; this site does not reproduce it.
- ISBD Legacy build plans Official plan describing the design-led class and its 275-pound combined limit.
- ISBD Race Week VIP and inspection guidance Official inspection-corner examples showing recurring failures such as cable routing, washer stacks, altered holes, brake hardware, excess filler, and plan-inconsistent assembly.