What is a Vehicle Retarder?
2 Answers
Retarders are auxiliary braking devices for large vehicles (trucks, buses), enabling heavy vehicles to decelerate smoothly without consuming the main braking system, and are not found in passenger cars. Below is relevant information: 1. Electromagnetic retarder: Essentially a "generator" installed on the driveshaft. When not electrified, there is no contact or wear. When deceleration is needed, the driver turns on the switch on the dashboard, and the driveshaft encounters resistance from the electromagnetic field, achieving braking. It automatically disengages when the accelerator is pressed again. Advantages include no wear, while the downside is its bulky structure. 2. Hydraulic retarder: Adds a turbine chamber at the rear of the transmission housing. When the braking circuit is activated, transmission fluid is pressurized in the turbine to create damping for braking effect. It causes no wear but requires additional cooling.
I've been driving big trucks for 20 years, mainly hauling goods in mountainous areas, and a retarder is absolutely essential. A vehicle retarder is an auxiliary braking device that helps you slow down without relying on the main brake pads. It's not a brake pedal but generates resistance through eddy currents or hydraulics, such as when triggered during long descents to prevent wheel overheating and loss of control. The common type is the eddy current retarder, installed on the drive axle for easy operation. After installing one on my truck, the lifespan of the brake pads doubled, and fuel waste was reduced, making it especially safer in rainy or snowy conditions. If you frequently drive on steep routes, a retarder can prevent emergencies, and maintenance is straightforward—just regular checks on the wiring and oil pressure.
