What is the best action to take if a tire goes flat while riding?

When a tire goes flat while riding a motorcycle, the best action is to brake on the good tire and steer to the side of the road. This approach helps maintain stability as you bring the motorcycle to a stop. Using the brakes on the functioning tire allows for a controlled deceleration, which is crucial to avoid losing control of the motorcycle. Steering towards the side of the road provides a safe area to come to a stop, minimizing the risk of further incident or injury.

It's important to understand that a flat tire can significantly affect the handling of the motorcycle, making it crucial to slow down and steer carefully. The other options could lead to increased instability or accidents. For example, braking on the flat tire would be unsafe as it could cause you to lose control completely. Maintaining speed or accelerating could worsen the situation, heightening the risk of an accident. Thus, gently braking and maneuvering towards the roadside is the most effective way to handle a flat tire.