Centrifugal Brake
From The Angler's Dictionary — your encyclopedia of fishing rods, reels, and tackle
A centrifugal brake is a spool-speed control system in a baitcasting reel that uses small weighted pins or blocks to slow the spool during a cast. As the spool spins, centrifugal force pushes the brake pins outward against a friction ring inside the reel's side plate. The faster the spool spins, the harder the pins press against the ring, providing more braking force during the high-speed initial phase of the cast and gradually less as the spool slows down.
This self-adjusting behavior is what makes centrifugal brakes feel natural to many anglers. The braking force is highest at the beginning of the cast when the spool is spinning fastest and backlash risk is greatest, then tapers off as the lure decelerates, allowing the spool to keep feeding line smoothly for maximum distance.
Centrifugal brake systems are adjusted by removing the side plate and toggling individual pins on or off. More pins engaged equals more braking. Beginners typically start with all pins on and gradually reduce them as their thumb control improves. Shimano's SVS and SVS Infinity systems are well-known centrifugal designs. Centrifugal brakes tend to offer better fine-tuning than magnetic brakes in windy conditions but require physically opening the reel to adjust — unlike magnetic brakes, which use an external dial.