Vibration diagnostics

Vibration showed up when i left the house that April. The August before this i was forced to drag my bobtail down the side of a grain hauler in KC. Mainly cosmetic damage down the side, we were both going about 55 and i was losing speed while dragging. My ds steer did rub on his trailer tires. After that incident was the first time i heard the leaf springs pop side to side when turning hard, only happened rarely. Don't think this really had anything to do with vibration now that I've changed leaf springs all together with the shackle bushings.
That following November i had steer tires replaced with tie rod and 3 axle alignment. No vibration after this and truck seemed to run well still.
On the way to take time off at the house that March i had all 4 drive tires replaced in Oakley Kansas. Don't remember noticing any vibration from there to Casper.
I parked the truck where i had been parking for about a year without incident. That time property owner decided to have truck/trailer towed because of my trespassing.
After i left the house this time is when i noticed vibration the first time.
Tow company told me that they had to drop the drive-line to tow but i didn't see any evidence of this on the u joint bolts. I cannot say how they treated the truck when they towed it or if the towing is related or not. I suspect it is the root to the problem though. I was in the wrong when i was towed so i really didn't have a leg to stand on to complain or fight it. Been way too long to prove anything to get any relief from tow company now.

 

Just had 3 axle done last week with new steer wheels.
They did need to add about 3/32 on ds bushing rear axle and took about 1/32 off on ps front bushing. Sounds like you're right about the thrust causing the steer tire scrubbing, at least I'm hoping so. I'm watching closely to see if it starts again. The cupping on only part of the circumference really messed me up

 

Right, there's only a couple hundred rotating parts that could be the suspect after all...

 

Tried playing with the ride height again. Think it somehow got set wrong, probably the shop got the wrong height setting when they replaced the leveling valve. Admittedly i didn't confirm the measurement. I was very hopeful when i looked back at the build sheet for the truck and found the ride height is to be 8.5" and i took over an inch off where it was setting. That seemed to take some of the magnitude out of the vibration but it is still there and closer to the road speeds when it first started.

It has echos and is present at more points than this and is gone at some points. Mainly starts in range 25 to 30mph. Worst around 38 to 45. Little bit around 55 and comes back around 70 to 75.

Back to thinking drive-line. I have heavy duty drive-lines according to spec sheet. Really don't want to just replace them but i might. Might be able to remove them and have local drive line shop check them out...

 

Forgot to add. Vibration is hard when loaded but light when not loaded. When it first appeared it was like the front end was bouncing. Now it's more just the truck in general like riding on a rumble strip or polygon tires.

 

I haven't been able to try getting the drive lines balanced yet but might try that with the drive line shop. I've had all tires balanced with and without beads a couple times now as well as replacing the brake drums for good measure. I don't think it's very likely that a tire is the cause, it's hard to consider that the vibration would remain after changing tires and multiple times being balanced on machines. I think a bad rim would have been identified by now don't you? I don't know...