What makes up an RC?

Cars & Trucks


Suspension is the system of linkages and springs or shocks that allows the wheels to move up & down independent of the chassis or body. This is important for "soaking up" bumps in rough terrain, gracefully landing jumps, and getting the right amount of body lean & weight transfer in turns.

The main piece of the suspension at a given corner of an RC car is usually a plastic or metal piece mounted low and called an "a-arm." This connects to the chassis and to a smaller part (hub carrier or caster block) that ultimately holds the wheel. The a-arm is hinged at either end to allow up & down movement. Above the lower a-arm is either another (upper) a-arm or a thinner, simpler "camber link." This is roughly parallel to the lower a-arm and keeps the wheel standing straight up.

2WD offroad RC front suspension Double wishbone RC suspension

RC shock & springNext come the most fun part of suspension, the shocks. Toy RCs more often than not use coil springs mounted over "friction shocks." The term "friction shock" is, in nearly all cases, a marketing-inspired misnomer -- these "shocks" really only act as telescoping spring mounts. Springs hold a vehicle up and also prevent it from leaning over too far in high-speed turns. Shocks exist to absorb bumps, jump landings, and other sudden forces. True shocks have a piston attached to a metal shaft which protrudes from a sealed cylinder filled with silicone oil. The oil resists the movement of the piston, absorbing some of the force. Different pistons and different thicknesses of oil are available to tune the firmness of the shocks.

Depending upon the vehicle, whether it's 2WD or 4WD/AWD, and which end you're looking at, you'll find two or three small parts at the end of the a-arm just before the wheel. These parts can be a caster block, hub carrier, steering knuckle, or a combination thereof. Shown below is the front of a 2WD electric truck.

RC front suspension details

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