Weird vibration at 85 mph

[covidcommander]

2020 hcwb....Driving above or below 85 and the vibration/pulse is gone. 85mph and you feel the vibration through the steering wheel, brake and gas pedals and the floor boards.

Tire balance?
Driveshaft?

Any thoughts appreciated. Has nitto slicks on the back and stock tires on the front.

 

[Old Mopar Guy]

Driveshaft carrier bearing, but I would think you would feel that under most condition.

 

[covidcommander]

Driveshaft carrier bearing, but I would think you would feel that under most condition.

No, definitely only at/around 85mph.

 

[DavidKFla]

Check your tires. 1 might be bad.

Stock driveshaft?

 

[BULL]

Several members have reported wheel balance issues at particular highway speeds, this is the first place I would start.

Is yours a daily driver or a Sunday driver? Cars that sit more than others will tend to get this problem. Mine does as it tends to sit in the garage a lot, but it doesn't take too long on the highway at speed to fade away.

 

[DavidKFla]

Several members have reported wheel balance issues at particular highway speeds, this is the first place I would start.

Is yours a daily driver or a Sunday driver? Cars that sit more than others will tend to get this problem. Mine does as it tends to sit in the garage a lot, but it doesn't take too long on the highway at speed to fade away.

Good old flat spots.

 

[Old Mopar Guy]

Good old flat spots.

I dont think so. He’d feel them more frequently than just at those speeds. As suggested maybe wheel balance, lost weight?

 

[DavidKFla]

I dont think so. He’d feel them more frequently than just at those speeds. As suggested maybe wheel balance, lost weight?

Yep.

 

[AeroF16]

Second getting the balance checked. Could just be a bad tire as well.

I chased a very similar issue with a brand new set of Michelin PS4s tires. Balanced them a few times and it never went away. Finally, I rotated the rears forward and moved the fronts aft, the vibration changed, and Discount tire replaced two tires under warranty. All was good after that, first time I had ever seen it.

 

[1971demon]

Yep.

Edify me...this makes no sense to me...what happens @ 85...but not 84...or 86...

 

[BULL]

Edify me...this makes no sense to me...what happens @ 85...but not 84...or 86...

Harmonics

 

[1971demon]

Harmonics

So the vibration is there...it's just not noticed

 

[TraxMoe]

Second getting the balance checked. Could just be a bad tire as well.

I chased a very similar issue with a brand new set of Michelin PS4s tires. Balanced them a few times and it never went away. Finally, I rotated the rears forward and moved the fronts aft, the vibration changed, and Discount tire replaced two tires under warranty. All was good after that, first time I had ever seen it.

I bought a set of tires and had Discount Tire mount and road force balance them. I rattled my teeth loose it vibrated so bad. I swear they had a half pound of weights on the wheels. I took them to a shop that did the traditional balancing after they stripped all the weight Discount put on they only had a few small weights installed and all the vibration went away.

Just a word of warning that some of the techs at Discount Tire don't have a clue about balancing tires. Maybe they didn't calibrate the machine or have a clue about how to interpret where the machine wanted them to place the weights

 

[BULL]

So the vibration is there...it's just not noticed

Literally like a musical note going in and out of phase.

 

[covidcommander]

Edify me...this makes no sense to me...what happens @ 85...but not 84...or 86...

Well it

Check your tires. 1 might be bad.

Stock driveshaft?

Yep stock driveshaft
And drag radials are almost bald. One season from them.

 

[covidcommander]

Several members have reported wheel balance issues at particular highway speeds, this is the first place I would start.

Is yours a daily driver or a Sunday driver? Cars that sit more than others will tend to get this problem. Mine does as it tends to sit in the garage a lot, but it doesn't take too long on the highway at speed to fade away.

Sunday driver so it does sit in the garage unless it rains on the weekends

 

[BULL]

Sunday driver so it does sit in the garage unless it rains on the weekends

First thought is flat spots from sitting.

It's a PITA, but increase tire pressure while it's sitting (the factory delivers cars with 45psi to help combat this problem, lazy, or oblivious PDI techs will leave them at the factory storage pressure). Then reduce for driving. Personally I only do it during the Winter.

Does it fade away at all with driving, or does it remain constant?

If it's constant or severe, then check other things.

i.e.,
Tire balance weights
Drive shaft (especially if aftermarket)


Low speed would point towards the rear diff, but not likely if only at highway.

 

[DavidKFla]

Edify me...this makes no sense to me...what happens @ 85...but not 84...or 86...

Vibration.

 

[DavidKFla]

Well it

Yep stock driveshaft
And drag radials are almost bald. One season from them.

1 season and drag radials are done?? 🙉🙉🙉

 

[Jimmy N.]

Just a word of warning that some of the techs at Discount Tire don't have a clue about balancing tires. Maybe they didn't calibrate the machine or have a clue about how to interpret where the machine wanted them to place the weights

I would hope that they at least use a Hunter machine with road force balancing. Then, as you pointed out, the machine should be calibrated correctly. And it's quite important that the Smart Weight setting is turned off. Otherwise the tires won't be balanced nearly as well as they could be.

These days it's unfortunately much easier to find a store with the good Hunter equipment than one that also has a person who truly knows how to use it.

Heck, I recently got a set of tires and wheels from Tire Rack, and in normal fashion put them on the balancer since I know they use Smart Weight. This time the balancing was unusually bad. Not so much the numbers, but two of the wheels had weights 180 degrees apart, on the same plane.

On one I simply pulled the same amount off in both places, and sure enough, perfect balance.

Anyway, the amount of weights used really isn't an issue. I often end up with the wheel with the most weights having the lowest road force numbers. So much for putting the least amount of weights in the front...if the tires are correctly balanced.