So I found some c5 zo6 rims/tires for my 85 iroc, now I have a vibration at 60-70 mph. I have lca with relocation brackets, Adjustable panhard bar, adjustable torque arm with relocation trans mount, and one inch lowing Springs. Also 2inch spacers front and back for the rim/tires combo. With the 16inch iroc rims it drove very smooth. All I changed was the 2inch spacers and rims, and it's horrible. Should the angle be adjusted up or down word? Zo6 rims are 18rear 17fronts. Thanks for any help.

 

The pinion angle will not change with a wheel/tire change. You've got 3 different items that could be causing this new vibration, so it's probably a good idea to have the wheels re-balanced and go from there.

 

Probably the spacers, or a bent wheel. Your pinion angle did not change, so don't mess with it.

 

I had them balanced before they got put on, I could try again. I did notice that when I got then back from the balancing shop the drivers side tires were not inflated all the way, so I added air to 38psi all around. Would an inflated tire balance different than a flatted Tire?

 

Jack up the rear of the car enough to get the tires off of the ground. Have someone start it and put it in gear. Have them let the tires turn while you watch and see if there is any up and down movement or any wobble. Raise the front tires and turn them by hand and check them too.

 

I'll try that. You would think the guy at tires plus would notice that. Here's what I'm working with., would really love to get this driving smoothly again.