Scale & Units

Every circuit is built at one RC scale, and the scale isn’t just a label — it sets the lane widths, turn radii, and climb limits Circuit Builder checks your layout against. Pick it once when you start a circuit, and change it later from Circuit settings → RC scale if you need to.

The scales

Ten scales are supported: 1/76, 1/64, 1/43, 1/32, 1/28, 1/24, 1/18, 1/10, 1/8, and 1/5. 1/10 is the default for a new circuit. The four smallest — 1/76 through 1/32 — are desktop-scale proportional-drift toys rather than hobby-grade chassis, and Circuit Builder gives them their own, tighter steering-lock and climb figures for that reason rather than treating every scale as a smaller or larger copy of the same car.

Each scale’s numbers come from scaling a reference car’s real dimensions down by its denominator, not from dividing one set of course figures ten ways — which is why, for example, ride height doesn’t scale linearly with the rest of the car. Drift chassis run deliberately low, so a 1/10 car’s clearance is closer to a seventy-fifth of a full-size car’s than a tenth of it.

Lane widths

For every scale, Circuit Builder tracks a minimum lane width (usable solo, tight for tandem), a recommended width (enough for two cars to run door to door), and a comfortable width (roomy — entry straights, sweepers, wide transitions). These come from real course-building convention at the popular scales, not a single formula applied to all ten.

At 1/24, that works out to about 25 ft in the real world for a tight single-file minimum — in the same range as the tightest lane a real drift circuit operator (Meihan Sportsland) publishes — and exactly 36 ft once the lane needs to hold two cars running door to door. A layout that drifts under either figure is flagged, not blocked, the same as any other guidance here.

1/24 has one more property worth knowing, whether or not you ever check it by hand: a real foot at that scale is exactly half an inch, because 0.5 ÷ 12 = 1/24 precisely. That means a standard architect’s scale ruler — the edge marked half an inch to the foot, sold at any hobby or office supply store — reads a 1/24 circuit’s real-world dimensions natively. No conversion, no math, just the ruler.

Climb grade

Elevation guidance is scale-aware too, and it runs the opposite way you might expect: the larger scales (1/8, 1/5) get the tightest climb limits, and the small hobby scales (1/18–1/28) tolerate the steepest relative grade. A heavier, higher-momentum car breaks traction on a climb a light, short-wheelbase one shrugs off. These figures are Circuit Builder’s own convention for RC drift, based on how these cars actually behave, not a universal physical limit.

A layout that pushes past these limits is flagged, not blocked — a curve too tight for the car to steer, a lane too narrow for the scale, a ramp too steep, all show up as you draw, so you can decide for yourself whether to change it.

Feet or meters

Circuit Builder works in millimeters internally, but every number on screen displays in whichever unit system you prefer. Switch between feet and meters from the unit toggle in the toolbar’s overflow menu — it relabels every dimension on screen immediately, and the choice is remembered for next time.