I have a Quad cab short bed LT 4x4 and still have the stock 20" wheels 275/55R20. I recently did a RC 2" level. Prior to the level kit, I had very minimal vibration. During first year I had it, I did have a little more and took it to dealership. They rebalanced the wheels and the tech raised the pressure in all the tires to 35psi. This pretty much eliminated all the vibration except for occasionally very minor but wasnt very noticeable. I dont drive it very often so it was a couple weeks before taking it in for an alignment. Prior to the alignment, I noticed the steering wheel was turned a bit to the right while going straight. I think I put about 200 miles onto the truck prior to the alignment. I noticed that there was a slight increase of vibrations at higher speeds. After the alignment, I noticed quite a bit of vibration at 80mph. It would start at about 75 and very noticeable at 80. I didnt go faster than that so I dont know if it would settle down at even higher speeds. When I got a chance, I took a look at the alignment report which was kind of a waste of time because it was all Greek to me. I noticed the the before for Toe was in red but everything else was green. The actual adjustments were all green which assume means it's now in spec. It also appears only the Toe on both fronts were adjusted. I also noticed that on the rear, the right seemed to be left alone but the toe on the left was adjusted. On another sheet I got, it showed that the tire pressure was adjusted down to 32psi on all the wheels. All the tires measured out to 8/32 on tread depth and the truck has just over 38,000 miles on it. Shortly after starting the first trip on the highway after the alignment, I noticed that the right fronts were reading 33psi, the left rear was at 32 and the right rear was at 31. I picked up an air gauge about 75 miles into the trip and compared the readings on the DIC. The fronts were at 35 hot so I brought those up to 37. The left rear, I also added 3psi to bring it from 34 to 37. And the right rear, I added 4psi to bring it from 33 to 37. I know I need to go back and adjust them cold but haven't had a chance. The vibration did seem to be a better but dropped from around 80mph to around 72-73 and seemed to be ok at 80 now.
I am fully aware of the vibration problem as it has been discussed over and over again on this forum but mine seemed to be pretty much ok overall pre level kit running 35psi. The only things that have changed were adding the level kit and the alignment. So can anyone shed any light on what might be happening and what you think about my post alignment values? I really like the look from the level kit and really want it to work...