Vibration/shimmy over bumps after new tires

My 2013 Sport came with the GY all-seasons. To put it mildly, they sucked in the rain. So I wanted to "upgrade" them well before they were shot, even though they drove perfectly, no shimmies, shakes, wobbles or uneven wear. Truck was smooth as silk even over bumps.

I wanted a more substantial grip for winter so I chose the Kumho Road Venture AT51 and had the shop immediately perform an alignment. That's when all the trouble started.

Long story short... The truck now drives like a truck over bumps. At any speed, the truck vibrates over bumps. It's like the shocks aren't recovering. When the road is smooth, the ride is technically "mostly" smooth at any speed. Introduce a bump, and it takes time to settle down. Over your average road, the truck is in an almost constant ever-so-slight shimmy. You know, where maybe your seat and steering wheel may be steady but your pant leg is vibrating.

So I had them recheck the balance and the alignment. It still had the shimmy, so they faulted the brand new tires. They said they'd order another set but to choose another tire. So I chose the Firestone Destination AT. (Both tires had great online reviews on multiple sites).

The Firestones were a slight bit better but still vibrate over small bumps. They handle better than both the GY and Kumho's but the shimmy, shakes and vibration really annoy me. So I took it to another tire shop. They told me all the wheels were 2-2.5 oz out of balance. They rebalanced them and gave me back the truck saying it felt fine to them.

I immediately noticed it wasn't fine. Perhaps a VERY slight improvement but not fixed. Then I discovered the following day, the shop had lowered the tire pressures to 32 psi all around! The truck calls for 39 psi.

So, my questions are...
Are vibrations normal on pickups with all terrain tires? (My jeeps never had issues)
Should I pay another shop to recheck the alignment?
Could I have gotten TWO sets of bad tires in a row from two manufacturers?
Do I now need to upgrade my shocks and struts to calm the truck down with AT tires?

Looking for ideas. Has anyone else been in my shoes before? How can I get my truck riding smooth again? Thanks.

It could be the shocks have gotten weak or not stiff enough for A/T tires. It could be something to look into. Your keep was set up for A/T tires.


Sent from my iPhone using Tapatalk

Do you get HL tires like a 10 ply by accident. That will make a huge difference. A 10 ply tire usually has almost no give so when you hit a bump its a domino effect through the suspension and body when you hit a bump/pothole/imperfection in the road. I hate my BMWs because of the run flat tires are similar.

Id check to make sure you dont have a 3/4-1-ton tire on there!

my nitto's do this when they're cold.not so much after they've heated up,but still slightly.i run 33's,don't know what size you run but it may make a difference.

I have the stock 275/60-20's.

Here's what I tried today...

I put my spare on the Rrear and drove it around the block. It immediately felt better. Then I installed the tire that was on the rear to the Rfront and I felt a little vibration in the steering wheel but overall it was somewhat improved. Then I installed the tire that was originally on the Rfront to the Rrear and I lost "some" of the improvement.

So, at the very least, the tire that was on the Rrear has some kind of issue and is now affecting the steering wheel more than before.

I guess I'll have to try the same with the other side and then see what the tire dealer wants to do for set #3.

One thing is certain... I should not get a better ride with a temporary spare in the mix. The fact it immediately helped says a lot.

You might try having them road force balanced if you have not done that yet.....


Sent from my iPhone using Tapatalk

Both sets of new tires were road force balanced. Then the Firestones were re-balanced without road force because the 2nd shop said they were all out. But the re-balancing didn't help.

The original shop was supposed to road force them again with the shop owner present but they still haven't called me back.