Hitches, like many things, often have slight variations in dimensions. The critical dimension for a hitch receiver is the I.D. or Interior Dimension (the space inside the hitch); the critical dimension for a hitch tongue is the O.D. or Outside Dimension.
Our engineers have designed the tongues of our hitch racks so they permit no play. However, some hitch receivers may have a slightly oversized I.D. thereby resulting in play or wobble.
Tightening the hitch bolt completely will reduce most side-to-side play. If you experience up and down play (or tightening doesn't eliminate side-to-side wobble), consider adding a shim -most hitch installers will have shims available or make one by cutting and folding an aluminium can.
If you have further questions please contact us here, or by phone at 888-925-4621 during business hours.