Originally Posted by Superfragl

Hi all,
I have been driving my Crossfire since May 2019. It is 2004 limited with auto trans.
It recently developed a steering wheel vibration at speeds 40 and up. Mostly noticeable at 40 and barely noticeable at 75. The vibration is shallow but frequent, I would say, more frequent than unbalanced wheels usually cause.
The weather has gotten cooler in the mornings (MA) and this is when it started. Also, after a 30 min highway ride the vibration becomes less noticeable.
All suspension is in top notch shape - new ball joints, new tie rod ends, shocks, control arm bushings, steering stabilizer, steering box bolts are tight, wheels have been road force balanced, wheel alignment done, hub bearings repacked and adjusted properly.
I took the driveshaft off since I saw the support bearing rubber retainer was deteriorating - installed new rubber retainer and bearing as well. The rubber donuts are in good shape. U-joint is binding very little, barely noticeable when moving by hand.
Engine mounts appear to be fine from what I can see.
One thing I noticed when spinning front wheels by hand is that drivers side wheel is a bit out of round - not rim, but tire is kind of bouncing a little - not sure if that could affect anything. If I had a spare set of wheels I could rule out the wheel issue, but I don`t...
Asking for advice / help with this matter - what else should I check? What am I missing? Could it be that the rubber gets stiff when it is cold, causing vibration?