Every bot has a center of mass: the single point where all its weight balances, like the spot you could hold it up from with one finger. Heavy parts pull it toward them. A battery low in the floor pulls it down; a spinner on a tall mast pulls it up.
That balance point decides two different things.
A bot stays upright as long as its center of mass sits between the wheels. Tilt it far enough that the balance point passes outside the wheels, and gravity takes over: it falls. A wide wheelbase and a low center of mass mean you can lean a long way before that happens.
Wider wheels or a lower center of mass both make that angle bigger, so a harder shove is needed to tip you. A heavier bot also resists a shove: the same hit tilts a heavy bot less than a light one. In BotForge this shows up as the Footprint stat, which warns TIP RISK if your center of mass is already outside the wheels.
A dedicated flipper scoops underneath you and launches you straight up. Your wheelbase barely matters here: a wide stance stops you being shoved over, but a flipper does not push sideways, it lifts. So the lab above (a shove test) is only half the story.
What actually resists a flipper is a low center of mass (a top-heavy bot is up to 2 times as likely to flip; a low one only half as likely) and plenty of mass (heavy bots are harder to launch). If you cannot stay low, build an invertible bot that fights upside-down and ignores flips entirely.
A flipped bot is nearly helpless: wheels off the ground means no driving, and most weapons cannot reach. You wait out a referee count (about 12 seconds) or self-right with an arm (a "srimech", which works about half the time and costs power). Some invertible bots are built to work upside-down and ignore flips entirely.
In the Stability Lab, set a shove force, read the prediction, then press SHOVE IT to test it. Try to build a bot that survives a full-strength slam.