Balancing machine for balancing vehicle wheels, comprising: - a base frame supporting gripping and rotation means for gripping and rotating a wheel for vehicles around a balancing axis, - first sensor means associated with said gripping and rotation means suitable for detecting the unbalance of said wheel, - at least an electronic processing and control unit associated with said first sensor means for the calculation of at least a balancing weight to apply onto said wheel to balance said unbalance, and - at least an auxiliary detection appliance (6, 7, 8) associated with said base frame and having: - at least a rolling device suitable for pressing onto said wheel, and - second sensor means associated with said rolling device and suitable for detecting the behaviour of said wheel when pressed by said rolling device, said rolling device comprising: - a support structure (9, 10) for at least two rollers revolving around axes parallel to each, other, and - at least a flexible member closed on itself in a loop, wrapped around said rollers and having a substantially flat active section, suitable for pressing on said wheel to simulate the rolling thereof on the road, and a return section substantially opposite said active section, characterized by the fact that - said rolling device comprises at least a substantially flat contrast element, associated with said support structure (9, 10) in correspondence to said active section and on which said active section is arranged in sliding contact, - said second sensor means comprise at least a first sensor suitable for detecting the reaction force of said wheel oriented in a radial direction and at least a second sensor suitable for detecting the reaction force of said wheel oriented in a lateral direction, and - said first sensor comprises at least a first bracket associated with said support structure (9, 10) and supporting a first portion of said contrast element arranged on one side of the lying plane of said wheel and said second sensor comprises at least a second bracket associated with said support structure (9, 10) and supporting a second portion of said contrast element arranged on one side of the lying plane of said wheel opposite with respect to said first portion. - a base frame supporting gripping and rotation means for gripping and rotating a wheel for vehicles around a balancing axis, - first sensor means associated with said gripping and rotation means suitable for detecting the unbalance of said wheel, - at least an electronic processing and control unit associated with said first sensor means for the calculation of at least a balancing weight to apply onto said wheel to balance said unbalance, and - at least an auxiliary detection appliance (6, 7, 8) associated with said base frame and having: - at least a rolling device suitable for pressing onto said wheel, and - second sensor means associated with said rolling device and suitable for detecting the behaviour of said wheel when pressed by said rolling device, said rolling device comprising: - a support structure (9, 10) for at least two rollers revolving around axes parallel to each, other, and - at least a flexible member closed on itself in a loop, wrapped around said rollers and having a substantially flat active section, suitable for pressing on said wheel to simulate the rolling thereof on the road, and a return section substantially opposite said active section, - at least a rolling device suitable for pressing onto said wheel, and - second sensor means associated with said rolling device and suitable for detecting the behaviour of said wheel when pressed by said rolling device, - a support structure (9, 10) for at least two rollers revolving around axes parallel to each, other, and - at least a flexible member closed on itself in a loop, wrapped around said rollers and having a substantially flat active section, suitable for pressing on said wheel to simulate the rolling thereof on the road, and a return section substantially opposite said active section, - said rolling device comprises at least a substantially flat contrast element, associated with said support structure (9, 10) in correspondence to said active section and on which said active section is arranged in sliding contact, - said second sensor means comprise at least a first sensor suitable for detecting the reaction force of said wheel oriented in a radial direction and at least a second sensor suitable for detecting the reaction force of said wheel oriented in a lateral direction, and - said first sensor comprises at least a first bracket associated with said support structure (9, 10) and supporting a first portion of said contrast element arranged on one side of the lying plane of said wheel and said second sensor comprises at least a second bracket associated with said support structure (9, 10) and supporting a second portion of said contrast element arranged on one side of the lying plane of said wheel opposite with respect to said first portion.