America's Tire Wheel Balancing Procedure

[The Critic]

I recently had two cars at America's Tire for a routine tire rotation/balance.

I observed that the techs will not rebalance the tire if the balancer only shows 0.25 oz of weight needed, and will deem the tire acceptable. According to their techs, a tire that needs 0.25oz of weight should not display any vibration issues.

In both instances that I observed this practice, they were using a balancer that utilized the Hunter Smartweight software. When the balancer showed that 0.25oz was needed, it displayed that the static force to be exceeding the pre-determined threshold.

Now, I have noticed some slight steering wheel vibration at higher speeds in both cars where this balancing procedure was used, but it's not significant enough where I could truly say that it is a balancing issue.

In the past, the America's Tire shops have always balanced the tires for me until the balancer said that the tires are balanced completely, but apparently this has changed.

Thoughts on this matter? CapriRacer? Has anyone else experienced this?

Thx.

 

[CapriRacer]

First, balance machines round off the weight needed to balance an assembly. I assume it can be turned off on many machines, but that is certainly true for the Hunter GSP9700. We've turned it off when we were doing same research.

So the 1/4 oz imbalance is really between 1/8 oz and 3/8 oz.

Second, I tend to agree that 1/4 oz. doesn't cause much of an imbalance - except maybe on some sensitive cars. But my experience here is limited.

But you mentioned "static force" - which I assume means the "Road Force" as Hunter likes to call it. And I assume that the shop didn't reset the value built into the machine which is 26 # for Passenger car tires. The value appears on the right side of the screen.

If that value is exceeded, then that is what I think the problem is. You should go back and tell them you have a vibration. What they should do is remeasure the tire, perhaps reindex the wheel to the tire to obtain a lower value, then rebalance the assembly. They just might not be able to get a lower Road Force value - and that means the tire needs to be replaced.

 

[The Critic]

Originally Posted By: CapriRacer

But you mentioned "static force" - which I assume means the "Road Force" as Hunter likes to call it. And I assume that the shop didn't reset the value built into the machine which is 26 # for Passenger car tires. The value appears on the right side of the screen.


Sorry for the confusion. I think static imbalance may be the correct term. I was referring to the icon on the left:

http://www.hunter-d.de/us/product/products/wb/5358te-05/images/A5358-18.jpg

 

[SteveSRT8]

With the larger wheels and tires fitted to many cars it would seem the Road Forced balance is a necessary procedure.

On my car it is the only way to get the high speed ride really smoothed out.

 

[eljefino]

If .25 isn't that big a deal, why do industry standard balancers and weight makers measure that small?

It can be a hassle chasing that .25 and as Capri said it's rounded anyway. It would be interesting to switch to static mode when in .25 heck and see if it at least zeroes on static.

 

[Chris142]

Here they just keep adding weight untill it reads 000. They put weights opposite the other weights then a weight midway between those sets of weights. On my truck there's a weight about every 120 degrees

 

[bigjl]

I would not be happy if I was paying for wheel balance and they felt that level of I balance was acceptable.

I have seen lots of wheels balanced over the years and until everything is 0.0 then it isn't balanced.

Would the tech be happy if the surgeon removed all but 0.25 of his gallstone or stitched up all by 0.25 of a wound?

I think it is more lazyness.

That is just my opinion though.

 

[Kestas]

Originally Posted By: Chris142
On my truck there's a weight about every 120 degrees.

I find that interesting. My state-of-the-art (at the time) 1954 SnapOn balancer is designed to place weights at the 120° positions. It has something to do with 3 equidistant balance points being better that 2. (One balance point being the heavy point of the tire).

 

[George Bynum]

Originally Posted By: eljefino
If .25 isn't that big a deal, why do industry standard balancers and weight makers measure that small?
A quick comment on the BALANCER ... in the science of measurement (metrology), we "typically" ask for accuracy and resolution of measurement equipment to be 10 times the required accuracy, and that in any case, they be better than 4 times. OCCASIONALLY science does not have equipment capable of that, and "we" analyze each case.

As for weights ... OPINION only ... 1/8 oz (3 or 4 grams) seems reasonable to (old days) split the weight in and out. Then there are true high speed applications where it matters.

 

[Colt45ws]

Originally Posted By: Chris142
Here they just keep adding weight untill it reads 000. They put weights opposite the other weights then a weight midway between those sets of weights. On my truck there's a weight about every 120 degrees

Ive never seen a need for more than one weight on each side. If the machine keeps coming back for weight at a different spot, I move or adjust the weight depending on the location. If I put 1.5oz in one location and it comes back wanting 0.25oz around 180° out, then I replace the 1.5oz with a 1.25oz. If its something like 160° out, then I will move the weight to bring it to around 180° out and pull .25oz. If its 40° out, I will add .25oz and move the weight towards it.

I dont like adding extra, unnecessary weight if I can optimize it out.

Most of the time I balance to .00oz, which really means it could be up to about .35oz as the machine wont ask for a weight until its sure adding it wont make the balance worse.
Out of boredom, and just 'cause, I have disabled the machine roundoff and cut weights (this was when lead weights were still around); doing that I am able to get down to about .05oz or so.
There are exceptions though. Large mud-bogger tires on 3/4+ ton pickups is usually one of them. In that case, I sometimes allow up to .5oz depending on what sort of trouble its giving me. I have had them come in and want upwards of 4, 5, 6 oz on each side! It gets ridiculous at times trying to get .25oz off of something that I have 10oz of weights on. I have spent 2 hours with another person helping me,(!) trying to get some of the stupid stuff I see balanced. Just not feasible to aim for max accuracy all the time; really they vibrate and run so rough anyway they wont feel it such a small amount.

 

[eljefino]

If you have something like a miata on 13 or 14 inch wheels with a tight suspension you'll feel it... as those little wheels sure do spin.

I like to put on about 80% of the called-for weight and respin. If it (or I) was off a little the small additional weight will compensate. Beats prying off a perfectly good new weight and potentially messing up its crimp for later. Also two smaller weights, with two crimps, have more stick-arounding power than one two-ouncer with a cheapo crimp. (There are better brands with wide crimps, truck weights, etc.)

 

[Ken2]

Quote:
Large mud-bogger tires on 3/4+ ton pickups is usually one of them. In that case, I sometimes allow up to .5oz depending on what sort of trouble its giving me.
Have you tried the balancing beads in tires like this? The combination of the large heavy tire, tall aspect ratio, and relatively small rim vs. the tire O.D. and weight on the O.D., plus the tires chunking if driven over rocks, makes the balancing beads a possible solution here.

 

[Colt45ws]

I dont have access to those sorts of supplies, or I would.

 

[CapriRacer]

Originally Posted By: The Critic
Originally Posted By: CapriRacer

But you mentioned "static force" - which I assume means the "Road Force" as Hunter likes to call it. And I assume that the shop didn't reset the value built into the machine which is 26 # for Passenger car tires. The value appears on the right side of the screen.


Sorry for the confusion. I think static imbalance may be the correct term. I was referring to the icon on the left:

http://www.hunter-d.de/us/product/products/wb/5358te-05/images/A5358-18.jpg


I've been thinking this over for the last couple of days and I am convinced that the problem is not balance. The problem is Road Force.

The icon you pointed to doesn't appear on the machine at work - BUT - I think it appears right above where the Road Force numbers appear.

 

[The Critic]

Originally Posted By: CapriRacer
Originally Posted By: The Critic
Originally Posted By: CapriRacer

But you mentioned "static force" - which I assume means the "Road Force" as Hunter likes to call it. And I assume that the shop didn't reset the value built into the machine which is 26 # for Passenger car tires. The value appears on the right side of the screen.


Sorry for the confusion. I think static imbalance may be the correct term. I was referring to the icon on the left:

http://www.hunter-d.de/us/product/products/wb/5358te-05/images/A5358-18.jpg


I've been thinking this over for the last couple of days and I am convinced that the problem is not balance. The problem is Road Force.

The icon you pointed to doesn't appear on the machine at work - BUT - I think it appears right above where the Road Force numbers appear.


The balancer they had definitely was not a Hunter model that was capable of measuring road force.

This was what the machine's screen looks like:

http://www.hunter-d.de/us/product/products/wb/5336T/images/Screen01.jpg

 

[CapriRacer]

Originally Posted By: The Critic
The balancer they had definitely was not a Hunter model that was capable of measuring road force.

This was what the machine's screen looks like:

http://www.hunter-d.de/us/product/products/wb/5336T/images/Screen01.jpg


Are you sure about that? The machine in our shop looks identical except that the icon is ever so slightly different - AND - it measures Road Force.

More importantly, the area you've been pointing to is where the road force number appears - AND - it indicates if the assembly exceeds the preset limits - just as you described. The balance weights don't do that.

 

[Carmudgeon]

My AT uses a lower end SmartWeight series machine without all the add-ons. Definitely not a road force balancer like the 9700 that has the secondary roller.

I get some minor vibrations now and again, but I think they're due more to flat spotted tires than any imbalance, since it's not consistent.

Speaking of the 9700, while it's the cream of the crop, the issue with it is that few people know how to exploit its capabilities. This includes techs inside a smaller OEM.

Around here, they're generally found in high-end dealerships. A high-end tire/wheel shop that caters to enthusiasts also has one.

The one in the local Firestone sits forlornly, again, because none of the guys know how or want to go to the trouble of using it.

As they say, a tool is only as good as the guy turning it.

On another note, I also noticed a brand new car with probably a 4-6" strip of weights inside one wheel. Yikes. Less is supposed to be more, right?

 

[tommygunn]

I'd use another shop.....that just seems silly...why even throw them on the balancer, with weight still on the rim? Just makes you do the work twice......


Unless it's a cost cutting thing (I see, at the Walmart TLE for example..... they go thru a LOT of steel wheel weights....they sell that lifetime "balance" package, and they get many customers who feel if they do not get their tires balanced and rotated every 3000 miles, they aren't getting "their money's worth".....sooo....yea...)

But yea.....seems silly, IMHO, to even balance a tire with weight on the wheel.


A buddy of mine works at the local TLE, and they get customers all the time, "Oh how far was it unbalanced?" And they go, errr....we don't know.....since they just tear the weights off, and then re-set the proper weights per the COATS machine.