Hydrofluorocarbon-Filled Tires?

Yes indeed. It would piss off all those holier-than-thou save-the-planet types. Go for it!

if you are trying to save money on fuel - then no - it would not be worth it - the cost of the gas would more than offset the fuel savings.

No point whatsoever, there have been several threads about filling tyres with everything from nitrogen to water.
The consensus is, it makes very little difference to anything.
I'd recomend filling them with custard...
Del

Hi Del,

Way back in the 1960s I had to fill one of my rear tyres with dry grass just so I could drive to the local garage (9miles away) and buy a new inner tube. This worked perfectly for about three miles, then I had to add some more grass as the first had been compacted while driving!!!

Spencer.

Excellent... nice one.
_{I think you'll find a little additional custard would have helped to lubricate the grass and stop compaction.}

Del

warning: I don't really know what I'm talking about!

The only possible benefit would be more constant tire pressure, assuming a significant portion of the hydrocarbon is at it's critical pressure. Note this is going to limit the gas mix to a specific pressure.

Hardly worth destroying the ozone layer and dooming all of mankind to a horrible death. Thanks for the replies.

Juggling Beatles

Hi route89,

Not a bad juggler..........as a matter of fact...........terrific.

Would there be any advantage to filling my tires with hydrofluorocarbon, like Ferrari does, even if I'm not going to be racing it?

Short answer, no.

the benefits accrue to the nitrogen or fluorocarbon sellers, I would expect, with this caveat:-

Furhairy runs at the max speed/temperature/pressure for tires. Are these aircraft tires/race tires they use the FC on? They might have valid reasons for the use of FC

If I remember correctly HFC are on the "To be phased out" list as from next year.

This is why many refrigeration manufacturers are going towards either CO₂ or LPG for smaller a/c and refrigeration units. Whenever possible with larger systems they will opt for ammonia.

I suppose you could use one of theses refrigerants in your tyres????

LPG could give you a real bang for your money!!!

Dry nitrogen is the best
But I think a friend of mine got the patent on it last year
Many tire shops here in the central US and racers started using it last year
The hard part is getting a good enough vacuum pulled on the tire to get all the air out
I don't remember the superior figures on nitrogen but very little change in tire pressure
year round and the racers love it

I used R-12 freon a couple times on an emergency to inflate a tire and they both blew
out when left parked in the sun a couple days later (before R-12 was banned)
The holes left in the tubless tires were about the size of footballs
Let's see - any liquid R-12 remaining at 105 deg I think equaled about 125psi
and hfc's run about 250psi It just doesn't work if the liquid changes state in the tire
but nitrogen doesn't change state at tire pressures and temperatures
from winter to summer

JR

Patent on dry nitrogen in tires last year? The military has used it in aircraft tires for decades. Military tires on landing get very hot and there is an appreciable amount of hydrocarbon vapor available at the extremes of temperature (high speed, high weight landing or fire) that a tire full of an explosive mixture is a risk to avoid. Racing watches for this risk too. For passenger cars they should not run in this regime, and should not need it. Truck tires at 100 PSI when hot also present a risk of over loaded and underpressured.

Wall flexure as the tire turns is like bending a piece of metal back and forth, it gets hot and fails faster.

That is why underpressured tires explode

I'm not sure people are understanding "why" you would want to use a fluorocarbon gas in your tires. This has nothing to do with the inert gas thing where the goal is to maintain constant pressure throughout a vast temperature range. Here the goal is to reduce driveline loss and get more crankshaft HP turned into RWHP. The slick gas inside the tires should remain stationary while the wheel accelerates, reducing rotational mass.

It sounds good, but I've got no idea how effective it really is.

The slick gas inside the tires should remain stationary while the wheel accelerates, reducing rotational mass.

That's bonkers....anyone care to calculate the mass of gas in a tyre?
You'd doubtless save more by empying the junk out of the trunk. Or drive with less fuel in the tank, or find a lighter passenger, leave your shoes at home...or eat less pizza.
Del

Alright according to this site which I found through Google, the air in a typical tire would weight 26g. It probably doesn't take much time to wear away 0.026kg of tread. So your right, the impact is likely too small to be beneficial.

http://www.madsci.org/posts/archives/2001-08/998945256.Ch.r.html

Excellent, so if you just empty the small change out of the gloce box, that should cover it.

It would probably be quicker and easier to have an attack of flatulence!!! Just open the windows and ventilate the car.......and there you have it.

The only thing is ..........whatever you do, don't follow through!!!!!!

Well it's not quite as simple as vacuuming your floormats, your rotational mass takes quite a bit of energy getting up to speed and contributes to drive line loss, the engines energy that doesn't make it to the ground.

Serious MPG savings or performance gains can be achieved through selecting lightweight tires and rims. But this is about removing several lbs (or kg for you) off the total wheel package.

Serious weight savings can be made by throwing away those ludicrous alloy wheels that are actually heavier than the standard steel rims.
Del

Ed, I don't think the cat can get his paws on a Glock in the UK. Perhaps he meant "mini-repeating Mongolian cross-bow" box.

Could that sort of "secret" be why Ferrari have been winning all the trophies recently?

Seriously, though, there are two ways this might provide some sort of benefit:
HFCs with very low vapour pressures ("liquids") might act as lubricants so it doesn't matter so much when the insides of the tyre contact each other or slide on the rim; or
The HFC is used to transfer heat by evaporation from the hot surface of the tyre to the rim - this would require a constant-enough temperature on the rim, unless combined with -
The quantities and types of HFC are designed so that the pressure inside the tyre rises to match the changing pull on the outside of the tyre as the tyre warms up, keeping the surface flat at lift-off (dubious, to say the least).

For myself, I think this is mostly gobbledygook to fill space on the publicity site without giving anything useful away. But even assuming validity, you would need to know exactly how to match the HFC to your conditions of use if you were to obtain any benefit.

I remember watching something on TV where they were inflating and then unmounting the tires in order to suction out a few drops of water that had been squeezed out of the rubber. Pretty extreme.

You should see what happens to rapidly-heated rubber when it has water trapped just under the surface. But I can't see that has much to do with HFC fills

............thats because if the tyre is heated to the boiling point of the water, under the conditions inside the tyre, as the water turns into steam........it expands 1700 times its volume............causing a rather rapid rise in pressure............BANG, and how!!!!!!

I'm not aware of the use of a hydrofluorocarbon (HFC)-based mixture designed specifically for use in race car tires but the use of nitrogen has many advantages. It is very stable throughout the temperature ranges experienced under racing conditions. Starting at ambient temperatures and under sever conditions reaching 300 degrees Fahrenheit any moisture expands raising the pressure and increasing the tire diameter in bias ply tires and increasing the spring rate in radial tires. If you increase the tires diameter it has a direct effect on the cars handling by changing the stagger used in setting up the cars handling characteristics. On radial tires increasing pressures increases the spring rates due to the change in side wall stiffness and is very useful in setting up the handling in which case you don't want any unintentional changes taking place once you determine the best setting. The use of moisture free nitrogen makes these adjustments possible by preventing the uncontrolled pressure changes. Another desirable reason to use nitrogen is the larger molecules are easier to keep in the tires. Any tire will lose pressure over time even using nitrogen but this lose is not as significant with the larger molecules. Safety is another reason, in the event of fire a tire containing air increases the danger while nitrogen is inert. The large dry molecules are excellent for running the tire changing impact wrenches on too. Jerrell

BAH! Balderdash! Horse-pucky! All gasses will expand at essentially the same rate when heated or cooled. The resulting pressure can be calculated by simple ratio of Rankin (or Kelvin) temperatures. (Tf2+460)/(Tf1+460) x P1 = P2, the pressure at Tf2 or (Tc2+273)/(Tc1+273) X P1 = P2, the pressure at Tc2.

Water is not a 'gas' by definition. Dry inert gas (nitrogen, argon, neon) will not react with rubber compounds nor attack the rubber. Dry air (78% Nitrogen) will work as well as dry nitrogen for most all purposes. The 'dry' is used to prevent any corrosion of the aluminum alloy tire rims used on aircraft and to avoid any potential for water condensation inside the tire when is chills down at high altitudes.

Automotive tires are more concerned about overpressure at higher than ambient temperatures during high speed,high load conditions. Water has a very steep vapor pressure/temp curve and if very much was inside a tire, the pressure would rise significantly more than normal otherwise.

All the hype about 'nitrogen filled tires last longer and give better fuel economy' is rubbish. It MAY be theoretically true regarding lasting longer, the effect is not realistically obtainable in real life service. The rubber in tires continues to polymerize with time, getting harder and losing tensile strength.THis IS NOT caused by the gas inside the tire but inherent in the vulcanization process. Ozone attack from outside the tire will cause deterioration.

An automotive tire more than 4 years old from date of manufacture should not be driven at freeway speeds as it is at high risk of failure.

Keith, Your statement, ("All the hype about 'nitrogen filled tires last longer and give better fuel economy' is rubbish. It MAY be theoretically true regarding lasting longer, the effect is not realistically obtainable in real life service") is what's " BAH! Balderdash! Horse-pucjt!" . Its fact that the use Of nitrogen in tires maintains the pressures set for a much longer period of time and that is what gives the benefits described in my prier post. Most people are driving around on under inflated tires due to the seepage of the oxygen molecules that make up about 20% of the air normally put in tires. The larger nitrogen molecules will remain sometimes for the life of the tire. Its this ability to maintain proper pressures that assures less rolling resistance and longer tire life. My F-350 gets 4 mpg more when the tires are inflated to 65 psi instead of 50 psi, this is a substantial savings in fuel. To do the job right you need to partially fill the tire with nitrogen and then purge the fill off and then refill to the proper pressure, this helps in evacuation of the undesirable molecules. Jerrell.

oxygen molecules and nitrogen molecules will not diffuse out through thick rubber for decades.

The rim and valve sealing is another matter. Even so I would not expect even 1% difference in the rate difference between them. I do find a lot of places who sell nitrogen espouse your cause. I suspect new car warranty people charge a fee for nitrogen test and fill, a few bucks? anyone know?

I think it is a scheme like gold audio cables

I think you a right about the diffusion through tyres being very slow, but even if not I can't see the difference between pure N2 and dry air being more than about 15% (the ratio of solubility of N2 and O2 in rubber is about 1:2). Rubber oxidation: the outsides of racing tyres get very hot for quite long periods, so that is conceivable, and in racing even fractions of percent longer life could make a difference. But that isn't applicable to normal road use (probably not even high-end rallying). I don't know enough about the behaviour of water vapour in tyres to comment whether drying the air would make a significant difference.

Rim and valve sealing? The molecular diameter difference is really small - less than 10%. And for leaks that are large enough to be significant it would be largely offset by the higher velocity of the lighter nitrogen molecule.

Gold audio cables? And I thought I'd heard them all!
Gold-plated connectors, single-crystal copper cabling...
Reference please - I could only find 'gold' audio cable as quality-style description (= branding?)