My 2011 4Runner shakes like washer on spin cycle, then smooths away.

Hi, my 2011 4Runner, 196K miles, runs great except that every cold start (first drive after sitting for a while) shakes as if seriously out of balance, then after a few miles it settles and runs smoothly.
I have had the tires rotated and balanced religiously every 6 months. This last summer I went to several shops trying to verify whether their balance machine might have been out, but no, it all came back positive.
I am suspecting perhaps suspension bushings being weak,or something along those lines. Has this happened to anyone?

 

Check your engine mounts. If they are OEM, they could be on their way out.
Start your car, engage the parking brake, give it some gas. Try it on both Drive and reverse. There should be some flex in the engine but it should not lift up. If it does, one or more of your mounts are broken. There are also transmission mounts that you can look into.

 

What does "sitting for awhile" imply? Days? weeks? months?...this sounds like it could be the tires going out of round (developing a flat spot) after sitting for a spell, once warmed up and rotated tires tend to recover 'roundness'.

 

No, what I mean is first drive of the day, or sitting for a few hours, long enough for everything to cool off. I drive daily.

 

Would this ease off after warming up?

 

I'm still thinking the issue is with your tires, what brand/model and psi are you running them at?

 

Bridgestone Dueler 245/60 20, 35 psi

 

Sounds like flat spots in the tires. Low tire pressures will cause the tires to "squish" and when they sit in one place for a period of time the tires will become hard and generate flat spots where the tire was sitting on the flat pavement. You have to put it on the highway at speeds and generate heat in the tire to get the tire to "heat up" and balloon back out to round. Most all of my vehicles do this after sitting a while, it takes about 5-8 miles on the highway at speeds for the tires to smooth back out. This isnt necessarily a problem, its just a slight nuisance. You could likely increase your tire pressure 5-10 pounds and reduce this happening or shorten the length of time it takes them to smooth back out.

 

Ok. While my prior experience with (not so consistent) cold vibrations were related to a slight under-inflation on my 2000 Limited, I was running 225/75 R15s....lots of squishiness on those. Ended up running 38 psi on em.

My 2021 came with Duellers (265/70 R17) and I found them to be a rather 'soft' tire. Comfortable on freeway but the soft sidewalls tended to give too much in tight turns. Since your tires are a lower profile I doubt profile is a contributor, however it is winter so it's possible the cold effects are to blame.

If it were sloppy/worn-out bushings you wouldn't find relief after 'warming up' a few miles.

 

Does it ease off once the car is warmed up and the rpms are settled?

 

It eases after a few miles, but I don't find relation to the engine temperature, but rather the tires warming up.
I'll pay a bit more attention to the engine temperature though.

 

Have you crawled under and inspected the suspension? The tires shouldn't flat spot unless it's very cold and the tires are cheap.

 

No, I haven't. It hasn't been that cold here (Austin, TX), and tires aren't cheap. I'll get under, and check the suspension this weekend, it's time or an oil change anyway.

 

Oh the memories of nylon tires.

 

If it's not cold I would rule out tires. Wheel bearings, bushings, etc would be my first look.

 

It's the tires.

 

How would wheel bearing act like that?

 

Absolutely, 110% guaranteed, by the way @PoloZ describes it, its definitely the tires. You will notice if you hop back in the vehicle after stopping like at a grocery store it wont do it. Leave it overnight it does it in the morning for the first few miles of riding. Definitely sounds like tires flat spotting, this isnt something bad, its quite normal but most people dont notice it unless you have a low tire that highlights the flat spots or makes them worse.
Yes, i run high end tires and my BF Goodrich TA/KO and KM3 were awful about this, i literally balanced the BFG AT like every 10,000 miles trying to get rid of the shimmy but as i got wiser i realized it was the tires and they smooth out after they got up to temp. Higher pressures is the only way to combat this or simply just live with it.

 

That's exactly what happens, first thing in the morning, but not anymore if moving around during the day. I'll look at the suspension this weekend while changing oil, just to say I did, but increasing air pressure is no problem, I have a compressor, and will do that.

Thanks everyone, I'll circle back next week with an update.

 

You guys should have been driving back in the day of "nylon bias ply tires".

 

in the days prior to radials!

 

My first tires i ever purchased, was a set of bias ply GroundHawgs. I learned the hard way when you went too fast or got them too hot you would hear a loud "thud" from the tires slinging off a lug into the inner fender.

 

Not all bias ply tires were nylon chord. It was an idea that didn't last long I think.

My dad had a set on his '57 Chevy and they thumped for the first few miles even in warm weather.