High Speed Bumpy Ride Mystery

[rgpinder]

My 2001 Yukon drive smooth as silk under 60, but around 60 or 65 it gets really bumpy. Now before you ask I just put some new tires (balanced) on it, and it helped to some degree but the bumpy ride is still there. What are the 1 or 2 things that might cause this? Wheel bearings? Other?

 

[Doubeleive]

my 03 Silverado used to be a bumpy ride, put new tires AND wheels (same size 22" wheels and exact same size tires as the old ones) rides like a Cadillac now, not saying it couldn't be other things but there is a HUGE difference on mine.

 

[SnowDrifter]

What do you mean bumpy?

Is it your road?

Different springs on the vehicle?

Shocks worn out?

Tires /wheels out of round?

Need more info here

 

[Danny3737]

Bent Rim
Drive Shaft

 

[Doubeleive]

What do you mean bumpy?

Is it your road?

Different springs on the vehicle?

Shocks worn out?

Tires /wheels out of round?

Need more info here

that's what I think was probably wrong with mine "wheels not round" because different tires didn't make any difference only when I changed the wheels, the shocks are still the same ones I put on mine 5+ years ago

 

[OneofFew]

What do you mean bumpy?

Is it your road?

Different springs on the vehicle?

Shocks worn out?

Tires /wheels out of round?

Need more info here

+1.
I'm not certain the OP is not referring to vibrations. A rough ride could be caused by high tire pressure. The faster you go, the more the suspension gets loaded, the more tire pressure effects the ride. GM suggests a certain tire pressure for ride quality, tire manufacturers list maximum allowable pressure.