Training wheels are an additional wheel or wheels mounted parallel to the rear wheel

Bicycle wheel

A bicycle wheel is a wheel, most commonly a wire wheel, designed for bicycle. A pair is often called a wheelset, especially in the context of ready built "off the shelf" performance-oriented wheels....

 of a bicycle

Bicycle

A bicycle, also known as a bike, pushbike or cycle, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a bicycle is called a cyclist, or bicyclist....

 that assist learners until they have developed a usable sense of balance on the bicycle. Typically they are used in teaching very young children to ride a bike, although versions for adults exist. The term "training wheels" is commonly used in the United States, Canada and Australia to describe the stabilizers' role in learning to ride bicycles.

Learning to bicycle

Training wheels that prevent the bike from leaning also prevent countersteering

Countersteering

Countersteering is the technique used by single-track vehicle operators, such as cyclists and motorcyclists, to initiate a turn toward a given direction by momentarily steering counter to the desired direction...

, so that, as with a tricycle, kids learn to turn the handlebars the wrong way, which must be unlearned later. Sheldown Brown

Sheldon Brown (bicycle mechanic)

Sheldon Brown was an American bicycle mechanic and technical authority on bicycles. He contributed to numerous print and online sources related to bicycling, bicycle mechanics and maintenance, including his own website — and received numerous awards for his contributions.-Biography:Brown...

 wrote that training wheels can become an obstacle to learning if they are adjusted incorrectly, because they prevent the bike from leaning if they are too low, and can inhibit braking if too much weight is taken off the rear wheel by training wheels that are too low. Adjusting training wheels correctly, and raising them higher as the child's skill increases, avoids these problems. Alternatives to using training wheels include removing the pedals from a kid's bike, or balance bicycle

Balance bicycle

A balance bicycle, or run bike is a training bicycle that helps children learn balance and steering. It has no pedals, no crankset and chain, and no training wheels.-Designs:Balance bikes have been made out of both metal and wood...

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