The Thunderdome rules
GT12 (On-Road)
v1Class RulesGT12Effective Sep 2, 2025· Updated 3 months ago
Summary of recent changes
Official ThunderDome rulebook (rev 2025-09-02). Discipline: On-Road.
Spec sheet
Governing
- Notes
- 3mm min ride height; 172mm max width; SXT Black sauce only
Motor & ESC
- Motor type
- Spec brushless
- Motor turn
- 21.5T
- Spec motor
- Gravity RC USGT spec 21.5
- ESC
- Blinky / zero-timing (ROAR)
- Blinky mode
- zero_blinky
Battery & power
- Battery chemistry
- LiPo
- Cells
- 1S
- Max voltage
- 4.20V
- Hard case
- Required
Tires
- Spec tire
- Any rubber 1/12 scale
- Tire additive
- Spec sauce only
Weight & body
- Min weight
- 750 g
- Body
- GT12 body with body-specific wing
Chassis & Suspension
- Chassis
- Any 1/12 on-road
1.Chassis Spec
Any 1/12th on-road chassis.
2.Weight Spec
Minimum 750g in race-ready trim.
3.ESC
Any ESC that is ROAR approved and running in ROAR approved "Blinky" spec software.
4.Battery Spec
ROAR approved 1 cell Lipo hard cased. MAX temp 90F at tech table. 4.20 MAX VOLTAGE.
5.Tire and Wheel Spec
Any rubber 12th scale tire. Sidewall glueing allowed.
6.Motor Spec
Gravity RC USGT spec 21.5 red end bell engraved with T, or Gravity RC USGT spec 21.5 black end bell.
7.Body Spec
12th scale GT12 body with body specific wing.
8.Ride Height Spec
3mm minimum.
9.Width Spec
172mm max width.
10.Race Spec
8 minute qualifiers / 8 minute mains.
11.Tire Sauce
SXT Black ONLY.