Strange Bounce after Parenting Objects on 2D Game

Hi, i had a issue with parenting objects together namely a board and 2 wheels, after i got to work around that im encountering a strange bouncing issue....

the objects have regular box and sphere colliders and rigid bodies to drop with gravity, while un-parented they just tend to drop and rest upon each other which is expected, intended, and just fine...

But upon parenting, as the whole rig drops to the ground, it now does a bounce, and if i wait till it hits the floor again it does an even bigger bounce no matter how close i place the object to the grond to avoid this...... How can i fix this?

Sorry for the noob question, still fairly new to unity :)

Thanks in advance :)