Earlier this summer I noticed the ol' H3 having a rough ride on the highway to work and back. It would kind of have a slight bumpy/shaky ride like a bad shock or out-of-balance tire. A couple of weeks ago I put on new shocks to replace the 105k miles OEM shocks. (One rear shock confirmed bad.) No difference - still this subtle roughness sometimes (it is not constant, but no apparent explanation). So I got the tires rotated and balanced yesterday. Same rough ride, even at 40MPH.

I don't remember it ever being like this. I'm thinking it slowly got worse to the point that I really noticed it being frequent, so my first thought was the old shocks and was confident that would fix it.

What else can cause this rough highway ride?

 

axles and driveshafts.

 

Body, suspension bushings or spring?

 

Great. All that stuff will be easy to diagnose. :-) I noticed the same kind of vibration even at 40MPH.

 

wobbly wheel bearings?

 

Or your tires are over-inflated. What is your tire PSI cold?

 

40PSI. The front bearings seem to be okay, haven't checked the rears yet. I thought about checking the tires for out-of-round.

 

good idea.

 

Your shop should have checked that when they balanced the tires!
Check your drive/shaft/axles.

 

Hummerz, you are the king of videos! I wonder if that guy would let me borrow his lift ...