Need help chasing down a vibration

Hi all,

I ask the following for two reasons:  you folks are a heck of a lot smarter than I am and I am currently living with a broken foot (which makes chasing down issues much harder!).

Anyway, we have a vibration in our 2021 Wrangler Unlimited with 29k miles and I would appreciate some opinions on where to look.

I feel a vibration on the highway between roughly 62 miles per hour and 75 or so.   Its reasonably smooth on either side of those speeds.  The Jeep was just aligned at the dealership and was actually rechecked when it went back in for a water pump.  I'm convinced the alignment is fine.

It has new wheels and tires I just bought from Tire Rack.  They mounted and balanced them, and I (thankfully) bought a set of 5.  Since I am confident the issue isn't the alignment, I'm betting its an out of balance wheel and tire.  The shake was not there with the previous wheels and tires.

I most feel the vibration in the gas pedal, and lesser in brake pedal and steering wheel.  I do not have significant shaking when braking hard to a stop.  When i ordered the wheels, I was supplied with the proper centering rings and lug nuts all of which is properly installed.  The inflation in all tires is right where it ought to be.

By nature Wranglers shake all over the place.  Even though these aren't huge wheels or tires (18x9 on 265/70/18 all season tires), they easily weigh 80+ lbs per corner which is a little more difficult to manipulate with a broken foot.  My intent (unless you guys point me in a different direction) is to use the 5th wheel to swap out one at a time to identify the culprit.

I ask you two things:  am I likely right that it's a wheel and tire and which end do you think its on (front or rear), and if not, where else should I look?  I thank you in advance for your input!

Wheel / tire balance sounds like a good place to start. Take it back to where they installed them and have them check. It should cost zero.

In reply to L5wolvesf :

Tire Rack shipped them to me and I installed.  I was asking which end, based upon the facts presented, is the end to look at first.

Maybe put it on jackstands and run it up to speed, and then you can take wheels off one at a time to try and isolate the issue? Should be faster than swapping the spare to each wheel.

The fact that it started with the wheel change suggests that it is some kind of wheel balance issue, or possibly a defective tire.

In reply to Loweguy5 :

Start with the front axle, 99% of the issues in a wrangler or gladiator are front axle related.  Make sure the bolts on the steering box to frame are tight.  Confirm your trackbar at the axle end and frame end are tight.  A wheel that much wider than factory is noticeable from the drivers seat.

Do you feel the vibration in the steering wheel or in the seat? Steering wheel, start with the front, seat, start with the back. Jack up individual wheel tire and check for lateral/radial runout visually. I have ordered many wheels/tires from TireRack with great results. However, I did have 4 tires returned to them because of balance issues. Does the Jeep have a steering stabilizer? The additional wheel/tire weight may be to much for the stock stabilizer to control.

Thanks to both of you.  I have double checked all the bolts on the front end and are tight.  I am wondering about the steering stabilizer among other things.  The funny thing is that people frequently run 37" tires and even bigger wheels in these things without issues so I'm perplexed why such a shake has developed.

I'll keep chasing it and appreciate your input.

In reply to Loweguy5 :

Just for fun, what air pressure are you running?  JLs are super sensitive to tire pressure.  With the bigger tire I wouldn't run more than 35PSI cold, and wouldn't hesitate to drop even lower.

Also with that many miles, I would honestly consider replacing the ball joints.  My 21 Gladiator has 25k on it (most of that with 37s) and the factory ball joints were toast when I swapped them out over the weekend.  Teraflex makes a decent set for about $300.

If it's not wheel/tire related in of itself, I suspect the additional weight is causing another component to be the failure point, especially a driveshaft. Just remember that at your speeds, the driveshaft is turning faster than the engine and transmission because of OD, and any minute difference is amplified. Given it's a Heep, I wouldn't be surprised if you don't have a bad hub or axle joint. Just because I've had one like this before from my wrenching days.

Loweguy5 said:

Tire Rack shipped them to me and I installed. 

Have you talked to Tire Rach tech support?  They're pretty good.

In reply to 914Driver :

Not yet.  I swapped each tire and wheel out one by one and it hasn't gotten better.  I'll call them.

In reply to Loweguy5 :

If it isn't a balance issue, it's either pressure, scrub, or a worn part issue.  Most of the time it's a loose trackbar at the frame side.  Drop pressure to 33psi cold and see if that changes it for better or worse.  I have a procedure to reset the electric power steering that might help also.

Mine needed ball joints at 25.5k miles..

In reply to JT1 :

I'll try that.  Running at 35 psi cold now which is factory recommended pressure.

I couldn't find any looseness in the track bar but I will take a good look at the ball joints.  I appreciate the suggestions as it's frustrating not to want to exceed 60 mph in a fairly new vehicle with such low miles.