I've had a vibration on my C43 and although the tires have less than 1K miles on them when I had them balanced originally it was not using the road-force balancer and was done at a local service station I use from time to time. I had all 4 wheels checked today on at a local place which has the Hunter road force balancer and they found one of my tires was way out of spec and could not be brought into spec. It was a rear and while the rebalance of them eliminated about 90% of the vibration I suspect that last 10% would be gone if I replace the bad rear tire. Unfortunately, I was informed that the tires (Sumitomo HTR-Z) are now discontinued but TireRack is trying to locate a replacement for me to swap it out. Even if I have to live with it now I can say it is 90% better and would not waste time and money using anything other than a road force machine again and I would say anyone fighting annoying vibration issues should locate one and have your tires checked on it first, even if a standard "balancer" said they were OK.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

Interesting as I have never read of a tire not beaing able to be balanced.

I do not know if what I suggest is worth the trouble or not but I believe the rims without the tire can be checked for balance and also trueness all by itself.
I have also seen where they put a wheel and tire on a maching that makes the assembly perfectly round by cutting off the high spots on the tire (before balancing). Even New Tires can be out of round.
I think some Members with a "Racing" backround would be able to tell you more about this.

I think also moving the Tire on to a different position on the rim and balancing again you might find a spot where it can be balanced but it it too much trial and error.

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84 300D, 82 Volvo 244Gl Diesel

The hunter machine tells them where to mount the tire on the wheel to counter the problem as much as possible and sometimes that is enough.

The issue is not that the tire isn't balanced, it is and a "normal" dynamic balancer would not show any problem with it. The problem is the road force (when the tire is run on a surface simulating the road) that even a dynamically balanced tire can have road forces that are uneven due to flaws in the tire or wheel. In my case the spec is a maximum of 18 lbs of road force and three of the 4 tires were around 8-9 lbs which passed with one over 40 lbs. Even after they remounted the tire on the wheel to minimize it, it was still around 35 lbs. The machine measures wheel runout and tells you if the wheel is OK or not and mine were OK, it was the tire which failed. The tire could have a bubble, bad belt, bump or high spot which causes the problem. In my case I think it was defective from new as my tires only had less than 1K miles and I knew there was an issue as soon as I put them on the car.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

MICHELIN

Spelled "ROUND"

OR

"Quality Controlled"

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'84 300SD sold
124.128

There was an article in The STAR not that long ago about the Hunter machine, every bit as complimentary as your experience, with one proviso. It takes a very skilled operator of the machine to get the most out of it. I have had one good experience and one bad experience with the GSP, which I would attribute to a skilled vs. unskilled operator.

That machine has a ton of settings and only someone who really knows it can make it sing.

Rgds,
Chris W.

I'm very finicky when it comes to wheel balance, so much so that I actually have a Coats 700 balancer in my garage.

When I got the balancer I was initially disappointed with my results, sometimes the wheels would balance fine other times well... it wasn't really bad but it wasn't perfect. The balancer always reported the wheels were in balance but when I mounted them on the car the results were not always "smooth as silk"

I began experimenting with the balancer and I noticed that if I mounted a wheel and balanced it then rotated it 90 degrees and re-spun many times the balancer would report that it wasn't in balance after I repositioned it. This puzzled me greatly because it seems to me that if a wheel was "balanced" that it should remain balanced no matter what its orientation on the balancer.

After a few weeks of trial-and-error I finally discovered the problem, the standard way of mounting a tire to a balancer is via a system of cones and cups that center the wheel on the balancer. The cup is mounted on the outside of the wheel and a threaded rod is used to put pressure on the cup and secure it to the balancer, the cone is on the inside of the wheel and automatically centers the wheel on the balancer shaft.

As it turns out this system isn't the best way to mount a tire to the balancer and frequently it introduces enough variability to the mount procedure that it will effect the balancing solution.

The cure is to use a "Pin-plate" mounting system where the wheel is mounted to the balancer via a plate and pins that secure the wheel via the lug nut holes - this system provides 5 discrete pressure points (in an MB application) and it is much more consistent and accurate than the cone/cup method used by many garages.

After I got the "Pin-plate" system for my balancer the results were quite dramatic, perfect balances everytime and when I balance a wheel and rotate to any other position it always stays in balance to within 2-4 grams.

I have no doubt that the road force balancer is a great piece of engineering but I can't help but think that many of these balance problems are the result of less than perfect mounting systems.

At least it was in my garage....

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98 Dodge-Cummins pickup (123k)
13 GLK250 (135k)
06 E320CDI (323K)
16 C300 (62K)
82 300GD Gelaendewagen (54K)

Like Tim I have a Coates Balancer in my shop also. A model 1001.

Where the Hunter balancer mentioned by the OP differs is that it goes beyond wheel BALANCE. It has a pressure roller that looks for stiff spots in the tire. It is a quite sophisticated machine in both balance and the stiff spot(Road Force Variation or RFV) capability.

Since I gave less than $1,000 for my old Coates and a GSP9600 costs about $12,000, I think I'll stick with my old Coates for awhile.

BTW Tim, in my Coates manual there is a procedure for checking the balancer for differing positions. I have never experienced the problem you described and I've balanced all sorts of wheel/tire combinations including the 80 pound combination that's on my 4X4 ranch truck.

The GSP9600, in my way of thinking, is not necessary for the vast majority of balance jobs or vibration complaints. When a problem child wheel/tire problem arises, the GSP 9600 is the equipment to resort to. Every MB dealer has one.

I have to agree that the smoothest machine balance I ever got was from a hunter road force. However, I'm experimenting with the beads inside the tire that they say will eventually put the machines into the scrap bin. I put them in a set of old mud tires on our 91 Chevy 1 ton and got the smoothest ride to date, which isn't saying a lot, but it was better than when it had lead weights on it. Since this is an experiment and I live in the country and don't have to drive it far, I bought the plastic BB's from Wal-Mart that were recommended on another forum. When I get new back tires for the 240TD, I might spring for a few oz/s of Dyna beads. I have a Coats tire machine so it isn't a big deal to play around with this stuff. I don't really pretend to understand the physics of why, but they do seem to work.