Wobble

Body shape decides wobble. Fat, round-bodied crankbaits push a lot of water and roll widely, which fish detect through their lateral line well before they see the bait. Flat-sided and balsa baits produce a much tighter, quicker shimmy that displaces less water.

The two suit different conditions. Wide wobble works in warm or stained water where a bait needs to announce itself. Tight wobble works in cold and clear water, where a big thumping action looks wrong and fish are moving slowly.

You can feel the difference through the rod. A wide-wobbling bait beats noticeably against your hand; a tight one hums. That feedback is also your snag warning, because a bait that stops beating has fouled.

Buoyancy plays into it. Balsa is lighter than the water it displaces by a wide margin, so a balsa bait floats up fast on the pause and hunts more erratically. Plastic baits are heavier and steadier, which makes them easier to fish and less lively.