vibration problem

[Moto-Mojo]

Imagine something like .010-.040 runout here by the time it gets to the greater diameter of the tire. (this is NOT a Camaro)

[PaulsSS]

Originally Posted by redcoats1976

the car is my 2015 RS,just back from the body shop last week.it rides good at speeds under 65 but when you take it to 70 or beyond it get a shake in the steering wheel and the passenger side seat vibrates.it has 4 new tires on stock wheels.not a huge lets depart the road and crash kind of shake but it wasnt there before.suggestions on my next step? i have already emailed my insurance adjuster.

Do you have some one that could follow you out on the road. Maybe they could spot something.

[fz4k98]

The tire had excessive runout or out of round. I had other issues too but this was an easy check at a shop.

[fz4k98]

You should try different conditions which may help narrow it down. Does vibration change if you hold speed while stepping on brakes. Does it change if going around a curve. Does it change if applying emergency brake while holding speed? Does intensity increase with speed?

[Moto-Mojo]

I don't want to insult anyone's intelligence but this is what I mean if the hub is bent. It was hit by a semi after all.The farther from the bend the greater the distance from the vertical axis.

[redcoats1976]

im thinking your theory is good.have an appointment at firestone tomorrow to have the 3 tires i bought checked for balance at the body shops request,at which time im going to ask if they can run it up to 75 mph on the rack.if its the drivers rear tire/wheel/hub as i suspect that should show up then.

[oldman14ss]

tire guy told once that a half ounce of weight could cause vibration. if your vibration is confined to one wheel swap it with another on your car and see if the vibration changes location. that is if you have a square set up.

[NOT A 45]

Originally Posted by redcoats1976

im thinking your theory is good.have an appointment at firestone tomorrow to have the 3 tires i bought checked for balance at the body shops request,at which time im going to ask if they can run it up to 75 mph on the rack.if its the drivers rear tire/wheel/hub as i suspect that should show up then.

First off, it's not safe to free spin a tire at that speed. Secondly, any run out you could see with the naked eye would be felt driving through the parking lot. I agree with you that the problem is in the left rear. I like Fasnuff's suggestion if you can find a known good car, swap the rear tires and see if it goes away. I've done this before, but then again I have 100 cars on the lot to pick from. If it were me, I'd drop it off at the body shop and say fix it. They did not deliver you a completely repaired vehicle.

Also I want to caution you that if it was hit hard enough to damage the wheel you can bet your ass in about 6 months or so that left rear hub bearing is going to be making noise. I would insist with the insurance adjuster that that hub be replaced.

[Moto-Mojo]

Originally Posted by oldman14ss

tire guy told once that a half ounce of weight could cause vibration. if your vibration is confined to one wheel swap it with another on your car and see if the vibration changes location. that is if you have a square set up.

A wise man, that tire guy. ONE OUNCE of weight located 7.5" (radius) from centerline (15" diameter wheel) produces 100LBS of force at 1000RPM. More on a 20" wheel. (I wrote a driveshaft balance program years ago and it only goes to 15" dia)

[0stones0]

Originally Posted by NOT A 45

First off, it's not safe to free spin a tire at that speed. Secondly, any run out you could see with the naked eye would be felt driving through the parking lot. I agree with you that the problem is in the left rear. I like Fasnuff's suggestion if you can find a known good car, swap the rear tires and see if it goes away. I've done this before, but then again I have 100 cars on the lot to pick from. If it were me, I'd drop it off at the body shop and say fix it. They did not deliver you a completely repaired vehicle.

Also I want to caution you that if it was hit hard enough to damage the wheel you can bet your ass in about 6 months or so that left rear hub bearing is going to be making noise. I would insist with the insurance adjuster that that hub be replaced.

+1

[redcoats1976]

took it to firestone,who checked all wheels for runout,suspension and hubs for the princely sum of 10 bucks,as well as rebalancing all wheels,i bet you cant guess which wheel and tire were not balanced correctly.had it up to 90,,,smooth as silk.

[Moto-Mojo]

Originally Posted by redcoats1976

took it to firestone,who checked all wheels for runout,suspension and hubs for the princely sum of 10 bucks,as well as rebalancing all wheels,i bet you cant guess which wheel and tire were not balanced correctly.had it up to 90,,,smooth as silk.

The one that got punched by the semi? Or…ALL of them!

[redcoats1976]

it was the one that got semi-punched,actually its replacement.brand new OEM wheel,new tire installed by the chevy dealer...but yet they couldnt care to balance it right.then the service rep said to have the other 3 ( had all 3 new tires installed and balanced at firestone) checked because chevy would charge me to check them.i guess i should be glad i did.,..it would suck to pay chevy a lot more to do it incorrectly.our local firestone has been pretty good over the years.the old rim and tire were only good for the aluminum,big chunks just gone.

[Moto-Mojo]

Originally Posted by redcoats1976

it was the one that got semi-punched,actually its replacement.brand new OEM wheel,new tire installed by the chevy dealer...but yet they couldnt care to balance it right.then the service rep said to have the other 3 ( had all 3 new tires installed and balanced at firestone) checked because chevy would charge me to check them.i guess i should be glad i did.,..it would suck to pay chevy a lot more to do it incorrectly.our local firestone has been pretty good over the years.the old rim and tire were only good for the aluminum,big chunks just gone.

Too few “experts” really understand balancing and the associated problems that might cause them. Your experience is, unfortunately, too typical. Including how to troubleshoot and calibrate their own balancing machines.

Glad you got it sorted out!