Poorly balanced tires or incorrect alignment?

Guys, I am in the process of removing the 5.5 inch lift kit from my 2015 prerunner and leaving the truck with only 1 1/2 inch lift. So, I just got back from the shop from changing the 285/70r17 tires to 265/70r17 and the steering shakes a lot. The shop was Discount Tire and supposedly they did road force balance. I'm wondering if the steering shaking is a result of fast and crappy balancing or if it has to do with my current alignment, I have a 4 degree caster and since these tires are now smaller... I don't know! I'm a bit ignorant on that subject. I wonder if I should take the truck back to balance or remove the suspension first, re-align it (that would take me several days) and then take it back to balance and tell them the shit they did. What do you recommend?

 

Was there shaking with the larger tires and 5.5 inch lift?
Was getting the smaller tires the very first step in removing the lift?
You will have a far better case to get the tire shop to rebalance the tires under warranty before you start removing the lift.

 

Shaking at speed is an out of balance or out of round tire issue. If you mounted used tires they could have an imperceivable internal defect like a broken belt which would be felt at speed too.

 

Did you mention what brand of tires are now on the truck? And how old they are?

Here's reason I ask. I got nitto grapplers on, and there is one tire that bounces, kinda, it makes the passenger seat shake, it mostly makes it shake when mounted in the rear. I've had the tire rebalanced, and I rotate frequently. I've never hit a pothole or 4-wheeled to the point where I thought I could have bent a wheel. I HAVE lifted the rear using a jack, and properly blocked I have seen the tire as rotating and it appears to be out of round. Could that be your issue? I deal with it as is, and cannot wait to get new tires but I think I'll drive these as much as I can to get my moneys worth.

When that tire is on the front, then I get a little shimmy in the steering that is really annoying, so I prefer that tire in the rear.

 

Its the tires.

 

OP @sblspawn, what have you discovered on this issue? Get it fixed yet?