A gear ratio is a trade you make once and live with the whole match. The same motor can be a sprinter or a bulldozer. It cannot be both, and the reason is pure mechanics.
A reduction gear is a lever made of teeth. Gear the motor down by a ratio and you multiply its turning force (torque) by that ratio, but you divide the wheel's speed by the same ratio. Nothing is free: whatever you gain in force you give up in speed.
It is the same reason a truck has a granny gear for steep hills (massive pulling force, crawling speed) and an overdrive for the highway (little force, lots of speed). A dragster and a tractor run opposite ends of the same dial.
A taller gear should mean a higher top speed, but only up to a point. Push fast enough and drag fights back harder and harder until the motor can't overcome it. Past that, a taller gear buys you nothing: you are drag-limited, not gear-limited. Watch for this in the Gear Lab, the top speed bar stops growing at low gears.
Gearing up has a second payoff besides the ram: raw pushing power. When two bots lock up and both drive in, the arena gives each an anchor, its resistance to being moved, set by weight and gear. The bigger anchor holds its ground and shoves the other one aside.
So a slow 20:1 tractor, the one that lost the sprint and whose ram has faded, still out-shoves a stock bot. That is the granny-gear tradeoff made real. A light, low-gear flanker gets pushed around.
Grabbing pays off the very same way. A clamp latches anything, but the moment you tow a victim you are driving the combined weight, and your gear becomes the muscle that hauls it:
The clamp only holds about 2 seconds. A tiny low-gear bot can latch a giant, but in that window it barely moves it (and traps itself), so it just pins rather than tows. To run a grabber as a tow truck, dragging rivals into hazards, you build heavy and high-gear and accept being slow (the top-speed cap means a tow truck hauls strongly but crawls).
The RumbleBots drivetrain runs on this exact trade. Here's the line-by-line map, including the one place the game keeps it simple:
| Real physics | In BotForge / RumbleBots |
|---|---|
| top speed ∝ 1 / ratio | top speed = 0.3 × (5 / gear) — the gear ratio slider (1–20, stock 5) |
| more reduction → harder ram | ram damage = mass × speed × aim × 1.2 × √(gear/5) × 0.45 (peaks mid-gear). A wedge and armor cut it further; the Lab shows a clean head-on hit before armor. |
| more reduction → more pushing force | shove anchor = mass × (1 + 0.8 × gear/5) while driving in; bigger anchor pushes the other aside |
| more reduction → more towing force | hauling a grab you move the combined mass; tow accel = √(50 / total) × (gear/5) — gear is the haul muscle |
| more reduction also → quicker solo acceleration | solo acceleration is tied to weight (√(50/mass)), not the gear — the game's one simplification |
| drag caps the real top speed | friction (0.95/tick) holds you below the gear cap at low gears: you go drag-limited |
Once you see the trade, it's everywhere there's a motor or a muscle:
More force or more speed. The gears just let you choose.
Eight quick questions. Pick an answer to see why.