Two Young Girls Posing On The Old Sidecar

A sidecar makes the handling of a bike asymmetrical. Without a brake on the non-driven sidecar wheel, the sidecar will pull towards the bike under braking, and towards the sidecar under acceleration. While a sidecar pilot is described as driving rather than riding, with all but the heaviest rigs, the comparison to a car is weak. Driver and passenger body position affect higher speed handling, especially on dirt or other uneven surfaces. If the sidecar and bike geometry are not coordinated the combination will be unstable, especially at speed, with shimmy upon acceleration or deceleration, becoming a dangerous problem.
The motorcycle's steering geometry, originally set up for a tilting single track vehicle, is set up to turn slightly away from the drag imposed by the sidecar. Leaning the motorcycle by clamping it rigidly a few degrees opposite the sidecar is used, along with a few degrees of "toe-in" of the sidecar wheel toward the centerline of the vehicle, is used to provide a balance resulting in comfortable, straight line travel. Most sidecars are also fitted with steering damping devices, of either friction or hydraulic type, to lessen the effects of sudden inputs, as encountered on rough roads, upon the vehicle's handling.