Motorcycles with sidecars lean in the opposite direction when turning due to the principle of countersteering. Countersteering is a technique used by motorcyclists to initiate a turn by momentarily steering the handlebars in the opposite direction of the intended turn.
When a motorcycle without a sidecar is being ridden, the rider applies a slight pressure on the handlebars in the direction opposite to the desired turn. This momentary countersteering causes the motorcycle to lean into the turn. Once the motorcycle leans, the rider can then steer the handlebars in the direction of the turn to maintain balance and control.
With a sidecar attached, the dynamics change. The sidecar adds weight and stability to the motorcycle, altering its handling characteristics. When a rider of a motorcycle with a sidecar wants to turn, they still need to apply countersteering. However, due to the added weight and the sidecar's presence, the motorcycle leans away from the direction of the turn while the sidecar remains upright.
This happens because the motorcycle and the sidecar have separate suspension systems and points of contact with the road. The sidecar's wheel acts as a pivot point, and the motorcycle leans in the opposite direction to maintain stability and prevent tipping over.
The rider must be mindful of this behavior and adapt their steering inputs accordingly to navigate turns safely and effectively while riding a motorcycle with a sidecar. It requires skill and practice to master the unique handling characteristics of a motorcycle with a sidecar.