I am going to call them in the near future to see what they offer for other vehicles as well. I would be interested in putting these on the VW Beetle my wife drives and the Subaru Tribeca that we both drive as well as the truck.

Need to start saving my pennies again...

 

I had no idea these existed John. Now you got me thinking I need these....for my truck AND my trailer.

 

A tire almost always gives some vibration warning when it's coming apart. The early signs are sometimes not noticed in time to slow down/stop before it comes apart. These would mask the signs to some degree making it harder to notice.

I've had several tread separations & blowouts, all with 10+ year old tires. I've been able to stop or slow reducing or eliminating vehicle damage. The best defense is to not run old tires.

The upsides to perfectly balanced tires probably outweighs the small negative of masking a problem. These things could pay for themselves depending on where you get your tires mounted, some shops have a mount/balance price and not separate pricing. They're ideal for the DIY guy that doesn't buy the free rotation/balancing as well as guys that buy used tires or might have roadside repairs done. The other upside is that they balance the entire rotating assembly, not just the tire/wheel assembly.

 

I've run Centramatics for the last decade on my personal dually. With seven (7) tires that retail for $450 each, the $3,150 in tire replacement expense eclipses the less than 10% of that paid for the set of four Centramatics (which were around $288 at the time, or less than the cost of one tire).

Prior to getting Centramatics, I once located two local tire shops equipped with the Hunter 9700 Road Force dynamic balancing machines, and I brought each of them one tire and wheel assembly to "road force balance". I insisted on paying full price for the balance, rejecting any discount offered, even though I brought in the tire and wheel already removed from the truck. I explained that they will soon know why I didn't want any price break. After the tire tech chucked up and Road Force balanced my tire and wheel assembly to the nth degree on the Hunter 9700, finally resulting in 0.00 balance on both sides, the tech proudly unchucked the tire and wheel and rolled it over to me while grinning with satisfaction.

That's when I thanked him, and then asked him to PROVE that it was really balanced. Quizzical, he protested "Didn't you see the read out, 0.00 both sides?" Yes, I saw it, but please humor me and prove that it is balanced by chucking it up to the exact same machine that you just unchucked it from, and giving it another spin. If it is truly balanced, then the readings should remain the same as before... 0.00 both sides, right? He agreed, and chucked it up to the same machine, and started it spinning. And THAT'S when his grin gave way to a grimace. That's when he started scratching his head. How can the same tire and wheel, mounted on the same balancing machine, in the same ambient temperature, that the same technician just got done balancing to 0.00 on both sides, now suddenly come up as 4.50 off on one side, and some other amount on the other?

Because what is being "road force balanced" is limited to the relationship between the tire wheel assembly and the balancing machine, based on how it was chucked onto the spindle. If a trained tire technician, the SAME tire technician, is unable to chuck the SAME tire and wheel on the SAME machine in the SAME hour on the SAME day, then how could it be expected that the tire and wheel assembly will balance the same when bolted up to the rub rotor of the truck? The balance machine isn't the truck. And more importantly, the way the wheel is mounted and retained by the balance machine is not the same as the way the wheel is mounted and retained by the truck.

I conducted this test twice, with two different tire shops (Firestone and Les Schwab), and found the same inconsistent results in the attempt to road force balance a dually truck tire and wheel assembly on the same machine by the same technician with repeatability. Couldn't be done. And these guys tried hard too, once they discovered what I predicted. They got into it, to prove themselves. And each tech, after many attempts, finally gave up. No one had ever asked them to rebalance the same tire and wheel that they had just balanced immediately prior on the same machine.

To be fair to the techs, dually tire and wheels, by the extreme nature of their offset, are more difficult to balance. They might be able to achieve repeatability with less challenging SRW wheels. I didn't test that.

But what is unfair to tire shop customers is that most tire shops, despite having the latest and greatest road force dynamic spin balancing machine, do not have or use the Ford recommended Haweka centering adapters for hub piloted dually wheels on their fancy machines. Instead, the tire techs might use the standard set of adapters that shipped with the machine, or a cone adapter, which appears as if it would automatically self center by virtue of the cone shape. But I have found through these two shop experiences, and Ford has found (and explained in two TSBs on the topic) through their vast and well resourced experience, that conical adapters on spin balancing machines are inadequate retention devices to acquire balance on a dual truck tire and wheel. The wheel hub pilot is not tapered, and therefore only the corner edge of the wheel bore is "seated" on the cone, and can end up being locked down when not perfectly perpendicular to the axial reference of the cone.

As such, the balance of the tire is limited to the manner in which that tire and wheel was chucked up to the machine, and that chucking, once loosened, shifts the wheel's engagement on the machine's mounting cone, and once retightened, is now something that was not as it was before. Hence the wheel will read out of balance again, and achieving repeatable balance is not possible. Note that it CAN be shown to be repeatable if the tire tech respins the machine after the tire and wheel comes to a stop. But that isn't the test. The test is if the balance is repeatable after the tire and wheel is LOOSENED and REMOVED from the machine (which it would have to be in order to mount it on the truck). Once loosened and removed, and then put back on the same machine and retightened, the so called perfect road force balance previously achieved on that same machine with that same tire and wheel in that same hour... is not repeatable. At least not in the tests I observed at two different tire shops with the same brand of Road Force balance machine.

Centramatics help resolve that dilemma at speeds beyond 25 mph by offering continuous dynamic balancing irrespective of the various idiosyncrasies inherent in how the wheel is clocked on the hub. Since the wheels are hub piloted, lacking the "benefit" of tapered seats and conical lug nuts to dictate wheel placement on the hub as did the former lug centric wheels of previous eras of light trucks, there can be some slight variance in how the central wheel bore is piloted on the hub, as the hub land and the hub hole pilot cannot be the exact same diameter, else the latter would not fit over the former. Gravity usually biases the mounting gap widest at 6 oclock, unless actively compensated with mounting shims, wheel mount stud locating sleeves, or a prybar under the tire until the lug nuts are cinched tight enough to counteract gravity. We are talking about very subtle spatial differences here, but we are also talking about balancing masses rotating at 650 rpms.

Centramatics mitigate another dynamic balance dilemma: The off balancing effect from the typically asymmetrical accumulation of mud, snow, and gravel in tire treads that is amplified by the additional leverage from being positioned at the outermost part of the tire, furthest from the axis of rotation... the tire tread. The further away from the center axis of rotation, the longer the lever between the additional mass and center, and therefore the more impact any errant weight (like hunk of mud stuck in part of the tread, but not all the way around the tread) can have on rotational balance. This is why Equal type beads placed INSIDE the tire are so effective... their ring of distribution is flung all the way out to the inside of the tread belt casing, which is a larger circle with a longer reach and therefore a more effective lever than can be achieved by the Centramatics.

Yet beads, liquids, and other crap thrown inside the tire have been reported to cause other issues with the tire, as well as inconveniences when the tire goes flat. Hence the idea of a continuous dynamic distribution of shot beads suspended in a viscous, heat tolerant fluid held captive in a tubular torus attached via a thin flat disc to the wheel hub (the working principal of Centramatics). While disadvantaged by a shorter lever arm, the shot in oil is still capable of instantaneous redistribution to compensate for any material changes in the rotating assembly, including the acquisition, retention, and subsequent rejection of debris stuck in the tire treads.

The benefit of dynamic balancing rings mounted to the wheel hub extends to balancing the entire rotating assembly, including the hub and rotor itself.

As for my Centramatics.... I found a couple of issues with them:

1. One of them leaked. But I didn't know it was leaking. I thought the small puddle of oil at the bottom of my front wheel was brake fluid, as nothing else could explain the amber color and location. This leak was hard to detect because it didn't present itself when the Centramatic disc was sitting in the box, nor when sitting in my hands. It took the terrific centrifugal forces of driving down the road to expel the fluid, and the small puddle I saw was the drain of fluid flung and clung to the wheel, that slowly dripped down overnight. After locating, proving, and photographing the leak site (on the tube under a retention tab), I contacted Jerry at Centramatic (still Jerry, after all these years), and he very obligingly sent me another one no charge, no shipping, no hassle, no grief, no regret.

The replacement disc never leaked, nor did any of the other three original discs. Still running them today.

2. The disc flats are drilled for multiple applications, and this can present a fitment issue when aligning valve stem locations with the access holes on the disc for the rear dually pair on 19.5" wheels with five hand holes on the wheel. There are only two hand access holes on the Centramatic disc, so right away you can see the issue. 2 can match with 4, 6, or 8. But not with 5. Compounding the matter further is that the entire bolt circle of the Centramatic disc is riddled with holes to fit various applications having different bolt circle diameters, stud diameters, and number of studs. The correct constellation of holes that fit the pattern on my hub limited the clocking options on the disc for cross alignment with the hand holes (and valve stems), restricting access to the inside dual valve stem. Centramatic attempts to resolve this by making their handholds longer, and more oblong.

I found that these holes were not oblong enough. After discussing the issue with Jerry (many years ago), he said he would send a note to manufacturing identifying the issue. He also reminded me that since these are dynamic balancers, I cannot hurt them by drilling new holes in the mounting disc where I would like them. Even if I was not accurate in matching the material removed, the physics in the torodial ring would not be effected. Just as the ring balances the tire, wheel, hub, and rotor... it also balances the disc that holds the ring. I used hole saw to evenly extend the oblong-ness of both access hand holes on the disc, in opposing directions, which was enough to improve access to the valve stem of the inside dually.



Note that the foregoing issue applied to the 8 lug 225mm bolt circle diameter 19.5" wheel, which is the only application I can report personal experience with. It may not apply to the 10 lug 225mm bolt circle diameter 19.5" wheel, nor may it apply to 8 lug 170mm or 200mm bolt circle diameter 16", 17", 18", or 20" wheels. Nor may it apply to newer Centramatic discs manufactured in the last 8 or more years. But if it does apply to your application, know that center disc can be redrilled to match your needs, and that Jerry has approved the modification in my case.

Finally, be prepared to hear scratchy gravely noises at low speeds (below 20 mph). That noise is the shot and oil rolling along the bottom of the ring, because the wheels are not spinning fast enough to distribute the shot and oil evenly around the ring. Once speed increases past 25 mph, all that noise goes away, as the centrifugal force is then sufficient to evenly distribute the shot and oil in the torus tube, and hold it in dynamic suspension until falling below 20 mph again. Since wheel balance is more important at highway speeds rather than when trawling around a parking lot, the low rpm noise is a fair trade off for longer lasting tires and smooth vibration free operation.

 

^^^^good enough for me to be convinced..Now, wonder if Colorado can get a group buy, going...👍

 

Now that is a good idea!

 

Nope, no bro deals. Only full price for us paying customers.

 

I went from never hearing of these yesterday morning to being completely sold that I need these now. I think @Sous mention something earlier about trying all kinds of things to fix some oscillation at certain speeds and it ended up being his transmission. I am getting a new transmission in the next few weeks and I think I will install these as well. I can feel all sorts of different "vibrations" (slow; more of an up and down bounce) at different speeds. I hope between these 2 things I can get some of this smooth driving up to 90 mph that I have been hearing about in this thread and others I have since searched for.

@Colorado350 Thanks for sharing this. Definitely something I am serious about trying.

 

I looked into these a few years ago but just never parted with my cash. I might some day. Seems like a good idea. My new used fronts are "equal" balanced and seem good. I bought them slightly used on a set of wheels and that is how they came.

 

They have a fleet program, who wants to start a company and have us all be owner-ops so we qualify?

 

I just retired, but you can count me in as a customer.

 

My fathers' the acct. for Deaver. I'll throw a bone at him to see what/how we can go about it...Im in either way

 

sounds like it may be worth my ca$h....im in.

 

Maybe it's just an issue with road force balancers, or these guys did something wrong. That thing about the tapered cones not working in the dually's hole is complete BS since the cones don't meet any wheel hole the same way a vehicle's hub does. I had no problem doing the dually wheels for my motorhome and Toyota PU using a regular spin balancer and I had no training and little practice using it.

 

One of the companies I worked for used these on all 3 axles. I loved how much vibration they took out of the rig.

I did not realize they made them for smaller trucks though. Another thing added to the list...