Wheel balancing

I never heard of such thing but its sound interesting. But for me, I don 't like the idea of having anything loose inside my tires.

 

Would that be like the "self balancing liquid" that some truckers use?

 

see www.autobalance.co.uk a gel that is in the final stages of development with major tyre manufacturers that will balance to perfection and improve mpg

 

I recently had the tires on my 550 Maranello balanced. They removed any old weights and replaced them with one weight per wheel. This one weight was said to contain many fine beads, that successfully balanced the wheels. This might be what your friend is referring to.
Woody Byrd

 

Rotating metal will screw up police radar I'm told...

Ken

 

I guess what I should have said was "does it work like the liquid?.

The balls/silicone/liquid finds the "out of round" area. Fills it in and thus balances the wheel...

Neat idea since wieghts can fall off, look bad, etc.

 

my buddy uses bb's to balance his 37's on his cherokee.........

 

http://www.centramatic.com/

 

What about tire pressure sensors, like on my 575M? Sounds like this system will destroy the sensor in no time.

 

Check this out, it may be of some help or interest..................

I had the tires and wheels load balanced on some new state of the art Hunter balancer, by people who understood what the hell I was trying to achieve. The proper term for the balancing I believe is "load balancing". What takes place is the tire and wheel are spun and the diameter of the tire and wheel are plotted to determine the "high/low portion of the wheel/tire combination. (This is done while a pre-determined load is applied to the spinning tire). In this case 800 lbs to the front tires and 1000 to the rear tires. These figures were computed, figuring that the TR weighs 3600 lbs. and that the weight distribution at rest is approx. 1600 lbs. on the front and 2000 at the rear. After this the tire bead is broken from the wheel and the low part of the wheel is lined up with the high spot of the tire. Trust me the wheels, as well as the tires are not "perfectly" round. The measurement is in lbs.. I guess an easy way of explaining is if you look at the wheel and/or tire as being like a cam......the "out of roundness" being that it appears as a "lobe" on a cam and where that high spot is, exerts pressure, or where it is low it releases pressure which is computed and then you align the high with the low spot. Have I confused everyone yet? The actual measurements were as follows;
Drivers side front was 33 lbs. out of round. What you are trying to achieve is a weight below 25 lbs. So after re-aligning the wheel and tire........15 lbs. was achieved. The passenger front was well within the 25 lbs. or less. I was told by the technician that the driver would be hard pressed to be able to feel anything under 25 lbs.. The driver rear was fine at 13 lbs. and then the biggy was the passenger side rear at 44 lbs.. It was corrected to 24 lbs. and we put all four wheels and tires back on the TR. But first I opted for the tires to be purged of air and nitrogen was pumped into the tires at 34 PSI front/ 36 PSI rear. Nitrogen will not expand, nor contract, (raising and lowering tire pressures as they heat up or cool......always at the pressure prescribed......no fluctuation). Well first realize that I had two tire/wheel combinations that were whacked at a diagonal from each other, ie. driver front/passenger rear.

What an amazing difference .........immediately.........slow speeds, at highway speeds and as of this date up to 150 MPH....smooth as glass, rock solid on the road. Absolutely astonishing the difference...the TR drives completely different, in a very positive fashion!

I am very pleased.......... balancing and nitrogen came to a very inexpensive $80 total for four tire/wheel combinations. And to top it off I was invited back, for 2 more complete procedures at NO charge to correct the balances even further as the tires and wheels "settle in"...........I am very happy with the results and suggest this to any and all F-car owners. Hell I have an appointment on Friday to get all six tires and wheels done on my Chevy dually, it's that amazing!

Kerry ...the happy TR driver...........now!!
........................................................................................................

Well here ya go.................this is a link to the manufacturer of the machine that did my tires and wheels. There is a tab in the top right corner to locate a machine in your area! How's that for service..............

http://www.gsp9700.com


Kerry

 

It's been a number of years since I took a physics course, but I can't see any reason this would be true. Though different in atomic structure, Nitrogen is still a gas, and like the air we breathe being composed of approximately 78% Nitrogen, it absolutely WILL expand and contract just like Oxygen. Allegedly, Nitrogen has other "better" characteristics over just normal air (supposedly less likely to leak out of the tires, less likely to oxidize the rubber, etc..); however, most people who have studied this argument extensively will tell you that Nitrogen in tires is nothing more than a marketing gimmick. Theoretically, it should be slightly better than normal air, and if you've got $25 burning a hole in your pocket, I'd say go ahead, but at the end of the day, the difference in straight Nitrogen vs. Nitrogen and +/-20% oxygen, etc. mix should be imperceptible...........either way, it WILL expand and contract, because it's a gas) Anyone out there with much more chemical / physical experience than me have anything to offer?

 

To Hell with the nitrogen portion of the post.......My intent was to share the balancing information. The nitrogen "fable" has been argued at length here in many a thread. Damn I should have left that out! Kerry

 

Maybe I have a mental block, but wouldn't free-floating particles or liquid gel just go to the most eccentric spot inside the tire; i.e. the point furthest from the center of rotation?

If so, I would guess that such a weight distribution would then be seeking the opposite point from the one which would tend to balance the rotating mass...

And, maybe I am dreaming, but weren't such movable rotating weights promoted years ago - I could swear I saw such schemes in the back of Popular Mechanics etc. way back in the late fifties or early sixties.

Maybe somebody needs to re-educate me on this...

 

Just a note of interest. Nitrogen is used in almost all comercial aircraft tires.

 

Any special thing to ask for other than a 'Hunter' tire balancer? And is there a national chain that has these all over the country, or just hit and miss at specialty shops? If anyone knows of someone on the south Florida area (preferably Palm Beach county) that has one of these, I would defionitely get the tires on my car done there. Oh, and nitrogen only please!
BT

 

Most high-end shops have the GSP 9600 Hunter, but what yielded the results in the post above was the GSP 9700 "Road Force" balancer. Ask for that. Hunter has shops that have this machine identified on their web site.

 

Click on the link http://www.gsp9700.com

Click on the locate tab......upper right-hand side of page (image of tab is attached below)

enter zip code

DONE
Image Unavailable, Please Login

 

No, the nitrogen in the tires is a good thing. Maybe it does expand at "almost" the same rate, but that is NOT why people started putting it in. Nitrogen is inert. Plain old air, with 20% oxygen is corrosive. It can help oxidize an aluminum wheel while it oxidizes your tire from the inside out. Oxidation inside the tire is what makes those lil rubber balls you find when you break one apart. And those two simple reasons, as well as holding pressure over a longer period, are why the aircraft industry uses nitrogen not only to fill the tires, but also the stuts that hold up the airplane.

 

Oxidized tires! My Goodness! I guess I'm an idiot for waiting until the tread wears out before replacing them.

Let's count the number of times anyone has seen a tire fail because it rotted from the inside out... Boy, I couldn't think of any either. Every tire I've seen always cracks and rots from the outside first due to UV exposure. If that tire were actually in use on a car it would have been replaced far sooner anyhow due to the tread wearing out.

Aircraft use nitrogen for a number of reasons, none of which concern cars. In fact large transport aircraft are mandated by the FAA to fill their tires with nitrogen. There are a few reason for this:

It is believed that several aircraft have been damaged or lost due to instantaneous combustion of the tire in flight due to the oxygen in the tire reacting with volatile gases from the tire rubber. Nitrogen is inert and will not do this. Again recall that aircraft tires must operate over wildly varying altitudes, temperatures and pressures.

It reduces the chances of brake fires. Part of an aircraft's certification is it being able to withstand a certain amount of time (3 minutes I think?) with the brakes ON FIRE without the aircraft itself catching fire. Obviously if the tire held plain compressed air containing oxygen this would fuel the fire when the tire bursts from flame, while inert nitrogen will not.

Aircraft tires are required to go from 0 mph to 200 or so mph at the instant of touchdown. After the tire instantly heats up from accelerating to 200 mph it then heats up some more when asked to support tens of thousands of pounds of aircraft. Then it heats up yet even more when it's asked to stop the tens of thousands of pounds of aircraft. Aircraft tires run HOT. Nitrogen helps here because it's consistent; there's no concern about how wet the air is from an air compressor in Burbank or Tinbuctu and again nitrogen will not support combustion.

Aircraft operate at tens of thousands of feet where the air is very cold. Any moisture in the tire could freeze and cause pressure variances as well as chunks of ice causing wildly imbalanced tires during landing.

Aircraft tires are pressurized to hundreds of psi. It's far faster, cheaper and more convenient to fill them from a 1,500 psi bottle than from an air compressor.

The extremely high tire pressures in aircraft greatly increase the speed of oxidation for the tire and its wheel, again making it much more important to use a dry gas for inflation.

 

I'd like to go back to the original topic. I can see no reason why this added mass would automatically move to the location that reduces the rotataing unbalance of the whole assembly -- I couldn't find any real physics/engineering explanation on that site (so please let me know if I've missed it). If the tire carcass itself was vibrating in some sort of (undesired) higher mode shape at speed (think "funny car tire shake"), I could be convinced that adding a mushy 2nd mass into the system might retune or reduce the amplitude of the undesired vibration, but reduce the unbalance? -- I have to vote "no way" without further enlightenment.

 

The Company claims the dissimilar metallic composition of the balancer, i.e. steel mounting plate and aluminum balancing ring, dissipates wheel/tire heating while in operation. This feature is called "ThermoFlow" by the Company. Basic rules of thermal physics apply as different metals have different coefficients of contraction/expansion with convection heat transfer migrating to the metallic content with the highest coefficient of expansion/contraction, i.e. rapid transfer from the wheel/hub/tire assembly to the steel mounting plate to the aluminum tube.


I don't know about the balancing feature - but the heat transfer "Fact" is nonsense. For example, coefficient of expansion of a solid has nothing to do with heat transfer - and "convective" heat transfer requires flow of the material! Solids either radiate heat or conduct heat?

Cheers
Warren

 

Well, I see your in Texas so maybe we can excuse some of this

First off, there is no FAA rule that civilian aircraft need anything in them but plain old air. I am not even aware of a nitrogen rule for commercial aircraft, but there could be.

They might have 1500 psi in the tank, but its regulated just like an air compressor, fills at the same rate.

Civillian aircraft tires dont generally hold any more PSI than your car. 32-60 psi. Same with the air over oil struts, usually less than 50 psi.

Being it expands at the same basic rate, going from high altitude to low is no different than air.

But corrosion is. You may live in a nice dry part of the world, but that dont mean we all do. Aluminum wheels with rubber against them like to corrode. Nitrogen slows down that process. Having to break down a tire to fix a flat and having it stuck to the rim so hard it tears the bead and destroys the tire dont help me any. Neither does a pitted up rim. Anything that will slow that process or eleviate it altogther should be encouraged, not ridiculed.

 

The FAA was kidding?

There's no rule! Okay, there might maybe be a rule. Nice hedge.

Airworthiness Directive 87-08-09

June 1, 1987

http://www8.landings.com/cgi-bin/get_file?pass=12345&ADS/1987/87-08-09.html

The weight requirement stipulated would include most all airliners but not the majority of general aviation aircraft.

Not at hundreds of psi it doesn't. It takes a very large air compressor to generate any real CFM at 300 psi. The problem with an air compressor isn't in getting the high pressure, it's getting enough volume at that pressure so it doesn't take 2 hours to fill one tire. Bottles will fill the tire much faster.

I grew up around general aviation aircraft and what you say is true of them, but not of the airliners which are mandated by the FAA to use nitrogen in the tires. Airliners routinely use tire pressures over 300 psi. It take more than 32-60 psi in those tires to hold a 300,000+ pound aircraft up.

It's not what nitrogen does have, it's what it doesn't have: water vapor that may freeze or turn to steam. Water vapor inside a tire will freeze at high altitude and leave a wildly imbalanced tire for landing.

A given mass of water occupies less volume in its liquid state than it does in it gaseous state (steam). This means that if water vapor is present inside a tire the pressure rises as the tire heats until there is enough temp in the tire to turn the water to steam. Then the pressure builds at a much higher rate. Your pressure increase is no longer linear, there's a knee where the steam forms and rockets the pressure up (this is the only reason to use nitrogen in racing car tires). Goodyear has found that large aircraft tires heat 150-200 F degrees above ambient (so if it's 80 F degrees outside we're talking 230-280 F degrees) just taxiing to the runway.

http://www.goodyearaviation.com/img/pdf/effects.pdf

Even racing slicks do not begin to approach aircraft tire temps. A typical street car tire would fail long before it reached such temps. No real concern for water vapor in a street tire.

Corrosion at the low tire pressures cars use does not begin to approach the problems large aircraft (or semi trucks) see with their much higher tire pressures. No automobile tire not parked in a barn for 25 years is going to fail due to internal oxidation before it wears out its tread or cracks from UV exposure. Fact is that the mountains of tires you see behind every tire shop on the planet aren't there because they rotted from the inside out, they're there because they were worn out or punctured. Nitrogen is a great idea for large aircraft and trucks for a number of reasons, but cars don't operate under any of those conditions.