shadowkahn

I need to understand road force balancing better, because I need to fight someone about the vibration my car has had ever had since it got new tires.

I went to Discount Tire (yes, I know, I won't do that again). Got Falkens. They rode terribly even after 3 attempts at balancing. So I upgraded to Yokohamas. I can tell that the tire itself is riding better because the car no longer jiggles as much, but there is still a vibration. I took it to the Acura dealer to have them look at it and see if maybe something was physically wrong with the car, since it's still (barely) under full warranty. They re-balanced the tires on a Hunter road force machine that they said was calibrated 3 days before I brought it in. Charged me $60 and said that 3 of the 4 tires could not be balanced because they're defective. They have a "road force of 37, 42, and 51 pounds respectively."

That's where I need help. What exactly does this mean as far as the tire is concerned? Is it actually a defect in the tire? Does it mean the tire is out of round, or has a higher density of rubber in a certain area? Can a tire that has a "road force of 51 pounds" be properly balanced, or is it really defective and needs replacement?

Based on Discount's inability to balance the tires so far, I'm inclined to believe the Acura dealership, but I need to know for sure before I go in there and demand that they refund my $750 and pay for the balancing at Acura that was necessary because of their incompetence.

Turbonut

iTrader: (1)

Never operated one, so I'm certainly no expert on the equipment, but there are a couple of items I've found over the years. One is centering of the wheel. I've found on some wheels, the center cone on the wheel (Where the Acura center cap resides) had been compromised and the need to use the Hunter lug adapter was necessary, but that would be indicated by the wheel run out check. If the tires have a tendency to flat spot after sitting, balancing can be accomplished, but the Road Force cannot be accurately computed because of the flat spots, and Yokohama’s (depending on the model installed) have a tendency to flat spot, especially with the nylon belt used to stabilize the tread. If they do flat spot, the tires can’t be checked for Road Force until after, I believe, at least 10 minutes of driving. There is quite a bit involved when using the machine if a problem arises, tires need to be rotated 180 degrees and rechecked, then possibly rotated 90 degrees, etc, but from what I gather, is that the machine is quite easy to use if the directions on the screen are followed, but most shops don't want to be spending hours on a set of tires.

Elementary introduction video to the 9700:
http://www.hunter.com/pub/product/vi....cfm?v=7&cat=4

Explanation:
http://www.gsp9700.com/pub/technical/4202T/5THEO004.cfm

I had a vibration on our TL after new tires were installed and balanced on a machine that the shop has had for years and I’ve never had any problems in the past. They were balanced 4 or 5 times, long story short, took it to a shop that had a Hunter 9700 not a vibration in 2 years, but that’s only about 12,000 miles.

Always hard to believe that new tires are to blame, especially 7 out of 8 that were installed. Falkens, ugh!

smarty666

How did I know Turbo would be the first one to answer this?

shadowkahn

A lot of good info there. I watched both videos and read the explanation, but still have the original question. Nothing on that site says what an upper limit to road force is before you determine something is wrong with the tire. They said "set your limits realistically" but then didn't give any examples of realistic limits.

The dealership said 20 is the upper limit. Anything above that is defective. But if I go in to Discount Tire just saying "well Acura says these are defective" without being able to actually prove the numbers, I'm going to have a tough time making them give me my money back.

I've been searching, but can't find anywhere that explains road force limits. Do you know of a site I can look at?

Turbonut

iTrader: (1)

I say there is nothing wrong with the tires, 26 for cars 45 trucks. That certainly can change by repositioning the tire on the wheel and as I remember reading the thread they did not do that.

Take them back to Discount, take them for a ride and tell them to fix the vibration.

EAMotorsports

I work at a GM Dealer and ASE Master Tech. I use the Road Force machine a lot at work. Our limit for cars or trucks per GM is 24lbs of Road force. I can tell you that there is a HUGE difference in 4 tires that are in the 5-10lb range and 4 tires in the 20lb range. Sometimes spinning the tire on the rim can bring the tire within spec but most times it will only drop it 3-4lbs.

Roadforce is the measurement of the high/low spot in the tire under a load while spinning and also the hardness of the tire. At least this is how I have come to understand it.

You can still balance a tire with high roadforce but you will still have either lateral or horizontal runout that will either feel like a wobble or a up/down out of round type feel when driving...sort of a vibration type feel. The only way to get rid of that is a tire with lower road force.

What Acura told you is 100% correct.

EA

binhsterbinh

I completely concur with this statement. Anything in the mid to upper 20lb range will be noticeable in the TL. I ordered a set of F1 A/S mounted on wheels from tirerack that had this issue. I had a professional wheel repair shop rebalance them. They found one tire to be 47lbs and the 2 others were 27lbs after force matching. They recommended me to replace the 47lb one, so I did. The new replacement was still like 26lbs roadforce. Needless to say, my year with F1 A/S was a disaster from a vibration standpoint no matter how I rotated the tread. After a year, I called in for the F1 A/S noise TSiB and got my tires replaced with Eagle GT courtesy Goodyear. Eagle GT's were night and day difference compared to the vibration/shutter I had felt all year.

I'd make sure Discount refunds you money for those tires and get new ones like Continental DWS or RE960's. My cousin was able to get Discount to match Onlinetires pricing and swing a set of 245/40/18 DWS for like $750 out the door including TPMS service and tire disposal.

AMUA6

iTrader: (7)

Learn something new every day!

Turbonut

iTrader: (1)

Just curious in that a great many UHP tires will flat spot after sitting, so how can the road force be measured without heating up the tires? My Yokohama S.4's have seen .077", using a dial indicator, flat spot after sitting. They can be balanced without a problem, but the road force would be completely inaccurate without driving the tire first.

As I said, I'm curious.

shadowkahn

According to the training video, you're supposed to either drive the tire first, or run it on the balancer long enough to simulate driving it for a bit first.

Anyway, thanks to EA's explanation and Turbo's links to training materials (all of which I watched, and took notes), I was able to go in and show Discount how much they screwed up, 4 times in a row. (I didn't even mention in here that the actual balance of the wheels when I took them to Acura was 15, 20, 20, and 30 grams off respectively, which should have been caught on any balancer)

They are now going to replace the tires (again), this time with Michelin Pilot Sport A/S Plus - a pretty significant upgrade to the Yokos - and aren't going to charge me any extra for it. They're also road force balancing them on a Hunter 9700 (also without charging), and guaranteed that the work would either be perfect when I left this time, or they'd refund all my money AND pay for the $60 balancing I had to get at Acura.

Thanks guys!

binhsterbinh

Good deal. Pilot Sport A/S Plus are awesome tires. Getting them at no charge is even better considering they're way more expensive than Falkens. You shouldn't have quality issues or concerns with those.

Turbonut

iTrader: (1)

Just an FYI-The only way to get rid of the flat spot is to drive the ca, as the heat buildup will have the nylon go back to the proper state. You can run it on a balancer all day and the nylon will not change. The Michelin's do not have the propensity to flat spot, so you'll be good to go. Actually one time in JAnusary when the weather was nice, but cold we took the TL out after sitting for 2 months and the flat spots didn't fully expand until about 30 miles of driving.
Have them install 245/45-17 if you haven't already.


Also curious, when do you notice the vibration or jiggling as you call it, all speeds, high speeds etc?

shadowkahn

starts around 35mph. It's worst between 40 and 60. I haven't had it faster than 70, and it's still there.

Of course, this has changed every time it's been rebalanced, since they keep *changing* the balance of the tire without actually balancing them.

Turbonut

iTrader: (1)

Thanks for replying.
If you don't notice the vibration constantly, and notice changes after balancing, I say it's not the tires. It's a mute point now as your getting new tires but if it were the tires that are out of round for any reason, the vibration felt would be constant from low speed to high, as the "high/low” spots will cause a reverberation throughout the car every time that area comes in contact with the road surface, not just at a given mph, and definitely would increase in intensity as the mph grows.

Got to let us know how you make out.

shadowkahn

Well, I suspect that the fact that the tire shop couldn't get the damn things balanced in the first place, road force aside, is what made things keep changing. Remember that most of the problems were on the Falkens. After they upgraded me to the Yokohamas, I had a constant vibration at all speeds as you said, and when I took it to the dealership they found the road force problems as well as regular balance problems. The Falkens were probably not defective - it was just bad balancing (and the tires sucked just because the tires suck).

So really, it's only been re-balanced once on the yokohamas.

Go in to get the Michelins tonight at 5, so we'll see if they manage to pull it out of the fire.

TLer trash

I agree with turbonut. I think you may have more than a tire problem. Balance problems usually start above 50 mph and get more severe as speed increases. I'm also an ase master and we have the hunter 9700. Just some random facts and ideas: Road force limits vary depending on the source...honda says anything over 10 lbs should be replaced. [after optimizing position on the rim] Tire rack says 15 lbs for performance tires, 21 for passenger car tires, and 32 to 40 for truck tires.
Some places charge additional to "road force balance" a tire without actually moving the tire on the wheel. If you don't use the road force information to actually optimize the tire on the wheel [match mounting], you haven't gained anything.
In order for match mounting to work the wheel has to have some runout and the tire has to have some road force variance. For example; you can move a tire with road force variance on a perfectly round rim and nothing will change.
If you have out of round wheels, the more perfect the tire is the less chance there is that you can offset the runout by match mounting.
How the wheel is mounted to the car is important. The lug nuts have to be snugged down, then tightened, not torque one all the way down, and proceed.
Sorry, I don't know how to post links, but honda has some good info on all this in tsbs#B07110J, 07120E, 08010I, and08020E. That's 4 out of 5, I can't find the first one.
I've never seen road force numbers as high as that on any good performance tire.
Tire companies don't consider road force as a reason to reject a tire unless it is causing a customer complaint.
Lastly, we recently put some michelins on an integra type r that had road force numbers in the mid twenties. The customer was so pleased with the balance he called us back!

Turbonut

iTrader: (1)

^ Good Info

Another question for the OP-OE or aftermarket wheels?

EAMotorsports

Sorry forgot about this thread. Yes you are correct as GM recommends the tires be driven for at least 25 miles before Roadforce balancing them under warranty. When a new vehicle is sold on the lot you can not even submit a warranty claim on tires/vibration till after 1000 miles. I am not sure where they come up with that but its probably as you said that the tire must be heated up to expand and take a set.

EA

EAMotorsports

Dead on!

EA

shadowkahn

Well, the new tires are on. I didn't have much time to test 'em because a severe thunderstorm with golfball sized hail was on its way as I left the tire shop, so it was just a quick 6 mile dash down the freeway and into a garage. But the little time I did drive it, it seemed much smoother. We'll see what happens tomorrow when I drive it normally.