The Thunderdome rules
21.5 Sportsman Truck (Oval)
v1Class Rules21.5 Sportsman TruckEffective Sep 2, 2025· Updated 3 months ago
Summary of recent changes
Official ThunderDome rulebook (rev 2025-09-02). Discipline: Oval.
Spec sheet
Governing
- Notes
- 5mm min ride height; 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
- WGT-R CRC #2314 / eXcelerate XCE-3077
- Tire additive
- Spec sauce only
Weight & body
- Min weight
- 1105 g
- Body
- Any 1/10 oval truck body
Chassis & Suspension
- Chassis
- Any 1/10 pan car
1.Chassis Spec
Any 1/10th pan car.
2.Weight Spec
Minimum 1105g 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
WGT-R CRC rubber tires #2314 or WGT-R eXcelerate rubber tires XCE-3077. 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
Any 1/10th scale oval truck body. No air relief holes above trim line in rear. Tailgate and rear bumper may not be removed.
8.Ride Height Spec
5mm minimum.
9.Race Spec
30 lap qualifiers / 50 lap mains.
10.Tire Sauce
SXT Black ONLY.