What makes tires go out of balance?

[nutdriver]

Originally Posted by grampi
I'm taking the car into my mechanic next Friday. I have run out of things to try, and he can rule out or identify a problem with the CV joints/axles...if those are good, I would say it's a tire problem...


I would ask if they can do a road force balance. I would agree that it is likely that you have a defective tire. Maybe early thread separation.

 

[grampi]

Originally Posted by nutdriver
Originally Posted by grampi
I'm taking the car into my mechanic next Friday. I have run out of things to try, and he can rule out or identify a problem with the CV joints/axles...if those are good, I would say it's a tire problem...


I would ask if they can do a road force balance. I would agree that it is likely that you have a defective tire. Maybe early thread separation.


Will doing a road force balance identify a tire that is structurally bad?

 

[FordBroncoVWJeta]

Originally Posted by grampi
Originally Posted by nutdriver
Originally Posted by grampi
I'm taking the car into my mechanic next Friday. I have run out of things to try, and he can rule out or identify a problem with the CV joints/axles...if those are good, I would say it's a tire problem...


I would ask if they can do a road force balance. I would agree that it is likely that you have a defective tire. Maybe early thread separation.


Will doing a road force balance identify a tire that is structurally bad?

It will show unacceptable levels of road force. I would do this first before mechanic.

 

[Hall]

Originally Posted by grampi
I took my car in to Discount Tire Friday and they rebalanced and rotated all 4 tires. The shaking was still there. So I took it back and they rebalanced all 4 tires again. The shaking is still there. So now I think I either have a tire that has something wrong with it, like a slipped belt, or it has become out of round, or I have a CV joint going bad. I don't know what else could be causing this issue...
Let's presume they did a less-than-perfect job on the first attempt. You go back and ask them to re-do them, don't you think they actually will get them balanced as best they can ? If they can't balance it, I have to think they'll tell you they can't and what could be wrong. If it balances to acceptable values on their equipment, it means it's not the wheel and/or tire, but something on your car.

 

[litesong]

Originally Posted by grampi
Discount Tire......rebalanced and rotated all 4 tires. The shaking was still there...... they rebalanced all 4 tires again. The shaking is still there.....So now I think I either......I don't know what else could be......
When ya buy 8 used tires for $100 (or less), ya don't have ta worra 'bout tire imbalance or other problems. Just use one of the other $12.50 tires. Since I've been driving used tires tho, all of them have given no problems. I've even bolted on used wheel/mounted tires AND never needed balancing.

 

[CapriRacer]

Originally Posted by hallstevenson
…… If they can't balance it, I have to think they'll tell you they can't and what could be wrong. …..


I'm afraid you have a misunderstanding about what it means to balance a tire - and what it means when it is said the tire can NOT be balanced.

Unless there is a liquid inside the tire, it can ALWAYS be balanced. It can take a lot of weight, but as long as things don't move, enough weight can be added to get it to balance.

What it means by "Can't be balanced" is that when the tire gets put on the road, there is still a vibration. This vibration is NOT because of the balance on the tire. Typically it's because the tire has some non-uniformity (think out-of-round and you'll be close.) or something other than the tire (and wheel!) are out of balance - like the brake disc.

So the guy balancing the tire will ALAWYS get it to balance and he won't know if there still is a problem, But the driver will!

 

[grampi]

Originally Posted by hallstevenson
Originally Posted by grampi
I took my car in to Discount Tire Friday and they rebalanced and rotated all 4 tires. The shaking was still there. So I took it back and they rebalanced all 4 tires again. The shaking is still there. So now I think I either have a tire that has something wrong with it, like a slipped belt, or it has become out of round, or I have a CV joint going bad. I don't know what else could be causing this issue...
Let's presume they did a less-than-perfect job on the first attempt. You go back and ask them to re-do them, don't you think they actually will get them balanced as best they can ? If they can't balance it, I have to think they'll tell you they can't and what could be wrong. If it balances to acceptable values on their equipment, it means it's not the wheel and/or tire, but something on your car.


Unless there is something structurally wrong with a tire. A tire can be balanced and still cause shaking due to a slipped belt, or some other structural abnormally....

 

[Hall]

Isn't there a maximum amount of weights that should be used to balance a tire ? That's more what I meant - it might take "too much" weight to properly balance it.

 

[grampi]

I am now noticing a wobble, or one tire that seems to be out of round at speeds around 20-25 MPH. Is that a sign of a slipped belt? I didn't know tires could become out of round...

 

[CapriRacer]

Originally Posted by hallstevenson
Isn't there a maximum amount of weights that should be used to balance a tire ? That's more what I meant - it might take "too much" weight to properly balance it.


There are 3 problems here:

1) The amount of weight that it takes to balance a tire varies by size. Large tires will take more weight than small tires. Put another way, there isn't a single answer to the question. That's because this is all about mass distribution - and the further out the mass imperfection is (diameter), then more weight it will take.

2) Technically, there are imperfections in the tire manufacturing process that don't affect anything but that mass distribution. They cause no other problems, so how does one assign a max value?

3) The wheel can be a huge source of the imbalance.

But people tend to use 1 oz for small tires and 2 oz for big tires. That's highly subjective. In my opinion, when a tire (and wheel) exceed that amount, it would be worthwhile to see if the wheel is the source of the large value. Rotating the tire 180° relative to the wheel might yield a lower value.

 

[grampi]

My mechanic looked at my car Friday and said both of my front rims are bent, which I was not aware of. He said it was probably caused by hitting pot holes. He is going to replace both rims (steelies) and tires...

 

[HangFire]

Originally Posted by grampi
My mechanic looked at my car Friday and said both of my front rims are bent, which I was not aware of. He said it was probably caused by hitting pot holes. He is going to replace both rims (steelies) and tires...

Thanks for the follow up. While not what you wanted to hear, at least steelies are cheaper to replace, and you are on the short path to balanced wheels.

 

[grampi]

My mechanic replaced two wheels and two tires. I also had a wheel bearing go bad just within the last couple of weeks. I'm still trying to figure out what bent my wheels. I've never had steelies bend before, unless I hit a curb or something like that, which I haven't done. My mechanic said pot holes can bend them too, but I don't recall hitting any that were bad enough to bend wheels...at any rate, all is smooth again...