Suspension group for motorized vehicles comprising a main spring which extends between a first and a second end of the group, a main damper connected in parallel to said main spring said main spring being pre-loaded by pre-loading means which together press the spring in compression and impose a rest length thereon, namely the length assumed by the spring when there are no further external loads on the first and/or on the second end of the group except for the pre-load caused by the pre-loading means, wherein the first and second end are connected kinematically to a first and a second mass of the motor vehicle respectively, the first mass being a mass suspended by the suspension group and the second mass being a non-suspended mass.